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{{quote|You still don't understand what you're dealing with, do you? The perfect organism. Its structural perfection is matched only by its hostility.|Ash|}}
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{{quote|You still don't understand what you're dealing with, do you? Perfect organism. Its structural perfection is matched only by its hostility.|Ash|}}
 
{{AlienSpecies
 
{{AlienSpecies
|image = [[File: Isolation.png|300px]]
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|name = Xenomorph XX121
|binomen = ''Internecivus raptus''<ref>Latin: meant as "murderous thief" (Alien Quadrilogy DVD).</ref><br>''Linguafoeda acheronsis''<ref>Latin: meant as "foul tongue from Acheron" (comic books).</ref>
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|image = [[File:Isolation.png|300px]]
  +
|binomen = ''Internecivus raptus''<ref>Latin: meant as "murderous thief" (Alien Quadrilogy DVD)</ref><br>''Linguafoeda acheronsis''<ref>Latin: meant as "foul tongue from Acheron" (comic books)</ref>
 
|world = [https://www.avpcentral.com/xenomorph-prime Xenomorph Prime]
 
|world = [https://www.avpcentral.com/xenomorph-prime Xenomorph Prime]
|habitat = Anywhere
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|habitat = Has been shown to survive in a wide range of conditions
|height = 6-7.51 ft
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|height = 6 - 7.51 ft (~ 1.8 - 2.3 meters)
|diet = Unknown
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|diet = Carnivorous
 
|lifespan = Unknown
 
|lifespan = Unknown
 
|sapience = Semi-Sapient
 
|sapience = Semi-Sapient
|behavior = Highly aggressive towards any living lifeforms usually using stealth tactics to ambush its prey.
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|behavior = Displays predatory behaviour towards any living lifeforms, usually using stealth tactics to ambush its prey
|language = A series of hisses and shrieks ranging from deep to high
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|language = A series of hisses and shrieks ranging from deep to high-pitched
|reproduction = Through implantation of an endo-parasitic embryo into a living host via facehugger.
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|reproduction = Through implantation of an [[endoparasitoid]]ic embryo into a living host<br>Life cycle includes alternation of generations and metamorphosis
|sub = [[K-Series]]<br>[[Red Alien]]
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|sub = [[Bodyburster]]<br>[[K-Series]]<br>[[Neomorph]]<br>[[Red Xenomorph]]
 
|universe = ''Alien''
 
|universe = ''Alien''
 
|creator = Dan O'Bannon<br>Ridley Scott<br>Ronald Shusett
 
|creator = Dan O'Bannon<br>Ridley Scott<br>Ronald Shusett
 
|designer = H. R. Giger<br>Carlo Rambaldi
 
|designer = H. R. Giger<br>Carlo Rambaldi
|name = Xenomorph XX121
 
 
}}
 
}}
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The '''Xenomorph XX121'''<ref>''Alien: Sea of Sorrows''</ref>, better known just as '''Xenomorph''' (which literally translates to "strange form" from Greek ξενος, ''xenos''=strange and morphe=form) or the "'''Alien'''", is an extraterrestrial hive-based [[endoparasitoid]] species with a multi-staged life cycle, possibly originating from the planet [https://www.avpcentral.com/xenomorph-prime Xenomorph Prime].
   
The '''Xenomorph XX121'''<ref>''Alien: Sea of Sorrows''.</ref>, better known just as '''Xenomorph''' (which literally translates to "strange form" from Greek ξενος, ''xenos''=strange and morphe=form) or the "'''Alien'''", is an extraterrestrial [[endoparasitoid]] species with multiple life cycles, possibly originating from the planet Proteus (also known as "[https://www.avpcentral.com/xenomorph-prime Xenomorph Prime]"). One of the deadliest of all known alien species, these creatures require a host organism in order to reproduce. The appearance of the Xenomorph can vary depending on the host in which the Facehugger implants. The human phenotype is generally around 7–8 feet and roughly 136.0 to 181.4 kilograms in weight, with a long, muscular tail and large, curved, oblong head. The [[Xenomorph Queen|Queen]] of this species is generally twice as large (although some Queens have shown to grow even larger, some surpassing 100 feet tall if given time) and possess superior speed, strength and intelligence than their offspring.
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One of the deadliest of all known alien species, these creatures require a host organism in order to reproduce. The appearance of the Xenomorph can vary depending on the host in which the embryo is implanted. The [[Human]] phenotype is generally around 7–8 feet (~ 2.13 - 2.43 meters) and roughly 136.0 to 181.4 kilograms in weight, with a long, muscular tail and large, curved, oblong head. The Queen of this species is generally twice as large (although some Queens have been shown to grow even larger, some surpassing 30 meters in height if given time) and possesses superior speed, strength and intelligence compared to her common offspring.
   
==History ==
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==Biology==
It is heavily implied in the movie ''''''Alien: Covenant'''''<nowiki/>' that Weyland-Yutani's original synthetic cyborg David was the chief designer of the first Xenomorph egg and therefore the creator of the species. However, there are no solid facts as to the [http://drshawtestament.tumblr.com/post/131706510396/testamentofdrelizabethshaw origins of the Xenomorph species]; instead, there are many theories which cannot be confirmed. They may be an artificially created species, or they may have evolved naturally on a planet very different than our own.
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The physical form of a Xenomorph can vary widely depending on its life stage, hive, caste, age, and host. Its ability to incorporate genetic material from its host, coupled with the existence of numerous mutations and deviations which have originated naturally or artificially; makes the Xenomorph one of the most phenotypically diverse organisms in the galaxy.
   
In the film "Prometheus"<nowiki/>, it's implied that the Xenomorphs were created as biological weapons by the Engineers (born from Humans). To be specific, the android David (an android built to be curious and human-like) infected Charlie Holloway with a drop of the mutagen and Charlie then impregnated Elizabeth Shaw; resulting in a large Facehugger-like lifeform (aka Hectopod or Trilobite). Elizabeth, in pain from the creature growing within her, then removes the lifeform by entering the automated surgery table on-board Meredith Vicker's exclusive ship. The lifeform later encounters an Engineer and ensnares him much like a Facehugger; thus, creating the [[Deacon]] which highly resembled the Xenomorphs.
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A typical Xenomorph begins its life cycle as an egg-like creature (known as an '''ovomorph''' or simply '''egg''') which, when detecting the presence of a potential host, opens up to release the second stage: a small arachnid-like life form (named the '''facehugger''') which launches itself onto the host's face and impregnates it with an endoparasitoid larva. This parasite then consumes parts of the host from within and violently emerges from the host's chest cavity as a worm-like creature (grotesquely christened as the '''chestburster'''), which will quickly scurry away to find a safe place where it can molt and complete its metamorphosis into an adult Xenomorph, which happens, surprisingly enough, over the course of mere hours.
   
In ''''''Alien: Covenant'''''<nowiki/>', David was shown to be the chief developer of the first Xenomorph eggs that contain the "Facehuggers". Utilizing the now emptied planetoid Elizabeth Shaw and David landed on, preceding the events of '''''Alien: Covenant''''', David was able to combine the limited number of creatures and organisms available with the "Black-Goo" (not to mention Elizabeth Shaw's female reproductive system) to develop the first "Facehugger" eggs. David knew he needed Human hosts to eventually gestate the Xenomorphs to fabricate his fantasy of becoming a Lord Helix and creating something even better than his own makers. The Xenomorphs have come to be known as "the Perfect Organism" throughout the franchise.
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Although numerous varieties exist, adult Xenomorphs all tend to share some common traits: a vertebrate-like body, a protective dark exoskeleton, a long flexible tail, an elongated domed head and a toothed mouth hiding a secondary, extendable, proboscis-like inner maw. Little is known about their biology, but it is known that they eat with their inner or secondary mouths, not their outer mouths. This mouth is somewhat similar to the pharyngeal jaw of a moray eel. They also bleed an unknown and extremely corrosive fluid. This substance is dull yellow in color and often referred to as "blood", although whether it's used to transport nutrients through the body and/or serves principally as a defensive mechanism is not clear.
   
--> '''Engineer''' --> '''Human''' --> '''AI Synthetic''' --> '''Xenomorph'''.
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While the extremely corrosive fluids and tremendous resilience displayed by the creature might suggest an exotic kind of biochemistry, the fact that the Xenomorph not only feeds on Humans, but actually develops inside them, strongly suggests that its biology is carbon-based. The ability to inherit traits from its hosts also suggests that it incorporates genetic material from them, implying that the Xenomorph either has [[DNA]], or is able to read and convert DNA into whatever means it uses to store genetic information. There is evidence that the genetic exchange is mutual (i.e. the parasite alters the host's DNA as well), given that Ellen Ripley's clones were created in an attempt to gain access to the Xenomorph Queen's genetic material, which wouldn't be possible otherwise.
   
However, based on the ''''''Alien vs. Predator'''''<nowiki/>' film franchise, the Xenomorphs were depicted as a pre-existing species that were bred, reared and hunted by the Yautja intentionally for sport. Nonetheless, the '''''Alien vs. Predator''''' films are considered non-canon and therefore inaccurate.
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Xenomorphs operate in hives made of a resin they produce, mixed up with their salivar fluids. The most commonly-observed castes are Drones, Warriors, Praetorians and Queens. The Queen can be generated in more than one way: from specialized royal facehuggers, or maturing from Praetorians, which in turn can mature from Drones or Warriors; by a process referred as 'molting'. Judging from the condition that any Xenomorph variant can potentially 'molt' and grow into a Praetorian and then a Queen, the Xenomorph species is likely all female and reproduces asexually by a process called parthenogenesis: a reproductive method practiced by many species on Earth and other planets. Alternatively, it's also possible that the aliens are either hermaphrodites or practice sequential hermaphroditism, i.e. being able to change sexes during life, as is the case with some species of fish and amphibians.
   
The Xenomorph could be the result of genetic manipulation by [[Mala'kak]] (also known as the "Engineers" or "[http://aliens.wikia.com/wiki/Mala%27kak Space Jockeys]") as a terraforming mechanism about ten million years ago, but it went terribly wrong. As a result, the Xenomorph had become an entirely new species in the galaxy. This theory has been altered slightly by '''''Prometheus''''', when a Mala'kak presented containers filled with an unknown Black-Goo substance (known as "Chemical A0-3959X.91–15"). This chemical mutated harmless organisms into somewhat hostile creatures. When a male human, infected with this substance, inseminate their mate, it produces a different subspecies of "Hecto-Facehuggers" that can grow incredibly large. As shown in '''''Prometheus''''', this new subspecies, regardless of whether a Mala'kak or human host, would result in the "[[Deacon]]" or "Proto-Alien".
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===Intelligence===
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Most Xenomorphs appear to possess an intelligence level equivalent to that of a typical primate. It's well within their capabilities to learn relatively quickly, gathering information and making advantageous use of their environment. Although they do not demonstrate Human and [[Yautja]]-level intelligence as a species (such as abstract reasoning, introspection and technological advancement), their Queen appears to possess considerable acumen in her social behavior and manipulation of Human technology, such as cutting the power of the LV-426 colony and operating an elevator. While it may take considerable time for them to learn how to operate machinery<ref>James Cameron, director's commentary, ''Aliens'', Alien Quadrilogy boxset</ref>, other Xenomorphs have displayed fast reasoning and the capacity to find creative, counter-intuitive solutions to problems, as exemplified by a group which, after noticing that they were being contained, intentionally murdered the weakest so that the acid of the Xenomorph's blood would eat through the floors.<ref>''Alien: Resurrection''</ref>
   
Another theory, touched on in the '''''Expanded Universe''''', is they were the alpha predator of their own ecosystem on a nightmarish and harsh planet (assumed to be Xenomorph Prime, but there is no solid evidence). Without their native ecosystem to keep them in check, they developed into a separate dominant species. The [[Mala'kak]], the [[Yautja]], [[Humans]] and an unspecified, highly advanced humanoid species introduced in the comic '''''Alien: Reaper''''', began showing interest and started using them as means of sport, terraforming mechanism, biological weapons, food delicacies and scientific experiments.  
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As the adult Xenomorphs are known to inherit physical characteristics from their hosts (for example, when a Yautja was infected, the parasite later developed into a "Predamorph" or "Predalien") it is possible that the intelligence level of the creature may be influenced by its host as well. Furthermore, being an eusocial species, it is possible that the intellectual capacity varies for each different caste.
   
==Biology==
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Xenomorphs have demonstrated little emotion, though they are not completely devoid of fear, such as when they are in the presence of fire<ref>''Aliens vs. Predator: Requiem''</ref>, which they are vulnerable to. They have also been shown to communicate pain through shrieks or screams when attacked.
The physical form of a Xenomorph can vary depending on its life stage, hive, caste, age, and host, as well as varieties which have been genetically engineered by host species or genetically grown. The typical Xenomorph start its life cycle as an [[Xenomorph Egg|egg-like creature]] which, when detecting the presence of a potential host, opens up to release the second stage: a small [[Facehugger|quasi-arachnoid life form]] (Facehugger) which launches itself onto the hosts face and impregnates it with an endoparasitoid larva. This parasite then consumes the host from within and exits the body as [[Chestburster|a vaguely worm-like organism]], before growing very quickly and developing into an adult Xenomorph.
 
   
Although numerous varieties exist, adult Xenomorphs all tend to share some common traits: a vertebrate-like body, a protective exoskeleton, a long flexible tail, an elongated domed head, with nearly invisible eyes near the mouth, and a toothed maw hiding a proboscis-like inner mouth. Little is known about their biology, but it is known that they eat with their inner or secondary mouths, not their outer mouths. This mouth is somewhat similar to the pharyngeal jaw of a moray eel. They also bleed an unknown and extremely corrosive Fluoroantimonic acid type of fluid. It is dull yellow in color and often referred to as "blood", although whether it's used to transport nutrients through the body and/or just serves simply as a defensive mechanism is not clear.
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It has been suggested that Xenomorph nests may operate under a hive mind, or a collective consciousness directed by the Queen, who can call back and give orders to her subjects, both telepathically and vocally with shrieks. In some cases, the Queen Mother Xenomorph communicates telepathically with potential hosts, inducing terrifying dreams and religious visions, which may even lead to the formation of cults with the Xenomorph as a god-like figure, not dissimilar to the cults of [[Cthulhu]] and other such entities. The most famous example of this phenomenon might have been Walter Golic, who received supposedly telepathic messages from a captured Xenomorph; which ultimately led him to release it and let it kill him. He called this Xenomorph "the Dragon", and viewed it as a [[god]].
   
While the extremely corrosive fluids and tremendous resilience displayed by the creature might suggest an alternative kind of biochemistry, the fact that the Xenomorph not only feed on Humans, but actually develop inside them, strongly suggests that its biology is carbon-based. The ability to inherit traits from its hosts also suggests that it incorporates genetic material from them, implying that the Xenomorph either has DNA, or is able to read and convert DNA into whatever means it uses to store genetic information.
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There is evidence that the Xenomorph hive mind also includes a collective memory that passes along even at a genetic level. Through the tests conducted on Ellen Ripley, it is revealed that the memory passed from Ripley onto the new generation of Xenomorphs allows them to read and understand different languages. Events on the LV-426 colony and the USM ''Auriga'' show that the species excels at observational learning. Another case of observational learning can be seen following a Xenomorph escaping its cell. It had learned that the consequences of attacking the observatory glass was a jet of extreme cold (possibly liquid nitrogen), triggered by a large red button on the console. When a crewman entered the now-empty cell to study the hole through which the Xenomorphs escaped, one of them entered the control room and activated the button using its inner jaw.
   
===Intelligence===
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In the rare event that a Xenomorph finds itself under attack or otherwise vulnerable, it might display incredible creativity and cleverness. They are capable of moving quickly and silently in ventilation systems, despite their size, and will use such conduits for ambush, escape, or simply as an easy way to travel between areas.
Xenomorphs appear to possess a roughly similar intelligence to that of a typical primate, but have shown to learn relatively quickly, utilizing the situation around their environment. Although they do not demonstrate [[Human]] and [[Yautja]]-level intelligence as a species (such as abstract [[wikipedia:reasoning|reasoning]], [[wikipedia:introspection|introspection]] and technological advancement), their [[Xenomorph Queen|queen]] appears to possess considerable acumen in its social behavior and manipulation of human technology, such as cutting the power of the LV-426 colony and operating an elevator. In the director's commentary for '''''Aliens''''', James Cameron noted that the Xenomorphs in '''''Aliens''''' had been alive far longer than the Xenomorph in the original, and therefore had more time to learn how to manipulate basic-level machinery. However, the genetic Xenomorphs from '''''Alien: Resurrection'' '''learned very quickly that they were being contained, so they intentionally murdered the weakest so the acid of the Xenomorph's blood would eat through the floors, thus supporting the idea of fast learning.<ref>James Cameron, director's commentary, Aliens, Alien Quadrilogy boxset</ref>
 
   
As the adult Xenomorphs seem to inherit physical characteristics from their hosts (for example, when a Yautja became infected, the parasite that later developed into a "Predamorph" or "Predalien") it is possible that the intelligence level of the creature may be influenced by its host as well. Furthermore, being a eusocial species, it is possible that the intellectual capacity varies for each different caste.
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Xenomorphs are conscious of the effects of their acidic blood, and will use it to their advantage - to break out of Human-constructed confinement, or as a weapon. They show some military tactics (such as retreating when overwhelmed), and can find ways to get around certain problems (such as pushing the red button to freeze a soldier in liquid nitrogen in the afore-mentioned incident). They know that the darkness is their ally, and break lights to create cover.
   
Xenomorphs have demonstrated little emotion, though they are not completely devoid of fear as shown in '''''Aliens vs. Predator: Requiem''' ''when they are in the presence of fire. They have also been shown to exhibit pain through shrieks or screams when attacked.
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===Anatomy===
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[[File:Alien_1986.png|thumb|left|300px|Warrior Xenomorph]]
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A Xenomorph is equipped to be the perfect killing machine. They possess an exoskeleton much like that of a lobster, impenetrable to everything but the most powerful Human firearms (12-gauge shotguns, Pulse Rifles, and stanchion launchers are quite effective). Ash claims the creature's skin is made from "protein polysaccharides", so this would imply a substance similar to chitin. He also says the creature replaces its surface cells with polarized silicon, which is a very inert, heat resistant, and flexible polymer. This allows these creatures great environmental resistance. However, they are vulnerable to sudden, massive changes in temperature. It's been demonstrated that they can be destroyed by immersion in molten lead followed by sudden cooling with fire sprinklers, causing their silicon shells to shatter.
   
In the '''''Aliens''''' literature, it has been suggested that the creatures may have a hive mind, or a collective consciousness directed by the Queen, who can call back and give orders to her warriors, telepathically and with shrieks. In the '''''Aliens''''' comic book series, as well some novelizations (produced before the '''''Alien 3''''' film), it is suggested that the Queen Mother Xenomorph communicates telepathically with its potential hosts, through terrifying dreams and religious visions, leading to the formation of cults with the Xenomorph as a god-like figure. This is similar to the [[Cthulhu]] cult in [[wikipedia:H. P. Lovecraft|H. P. Lovecraft]]'s ''[[wikipedia:The Call of Cthulhu|The Call of Cthulhu]]''. This can be seen in '''''Alien 3''''', when Golic is induced by supposed "telepathic" messages from a captured Xenomorph. This ultimately leads him to release it and let it kill him. He called it "The Dragon", and viewed it as a god.
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Attached at the ends of both of their arms are a set of long fingers and shiny, black, extremely sharp claws capable of slashing through almost anything within their grasp<ref>Alien Book 2: ''Nightmare Asylum''</ref>. Their tail is long and flexible. Some, though not all, individuals also have ridges on top, and a serrated toxic tip at the end of the tail to lacerate enemies.
   
Through cloning in the events surrounding '''''Alien: Resurrection''''' (noted in the novelization), it appears that the Xenomorph hive mind includes a collective memory that passes along even at a genetic level. Through the tests conducted on [[wikipedia:Ellen Ripley|Ellen Ripley]], it is revealed that the memory passed from Ripley onto the new generation of Xenomorphs allows them to read and understand different languages. Events on the LV-426 colony and the USM Auriga show that the species excels at [[wikipedia:Observational learning|observational learning]]. Another case of observational learning from '''''Alien: Resurrection''''' is seen following a Xenomorph escaping its cell. It had learned that the consequences of attacking the observatory glass was a jet of extreme cold (possibly liquid nitrogen), triggered by a large red button on the console. When a crewman enters the now-empty cell to study the hole through which the Xenomorphs escaped, one of them enters the control room and activates the button using its inner jaw.
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They stand at around 7 feet tall (~ 2.13 m), averaging in anywhere between 140 and 180 kg; although size may vary wildly depending on the host chosen, as seen for instance with the "Jock-Xenomorph": a gigantic creature spawned from a [[Mala'kak]] host.
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[[File:Xeno head.jpg|thumb|220x220px]]
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A Xenomorph's outer mouth is filled with sharp teeth, but their main killing device is the inner jaw that shoots out to penetrate directly into the victim's brain. The inner jaw (also known as an "attack tongue") is a muscular appendage on the inside of the Xenomorph's mouth. All Xenomorphs have this trait, excluding the genetically-engineered [[Newborn Xenomorph]]. It consists of a cord of muscle with a small but extremely deadly mouth-like appendage on the end. This attack tongue is able to punch through almost anything, from bone to Yautja armor.
   
In the rare event that a Xenomorph finds itself under attack or otherwise vulnerable, it might display incredible creativity and cleverness. They are capable of moving quickly and silently in ventilation systems, despite their size, and will use such conduits for ambush, escape, or simply as an easy way to travel between areas.
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The plasticity of the Xenomorph phenotype is one of the species' most notable features, and has resulted in physical traits that diverge from individual to individual and from hive to hive. As an example of how a host can influence the morphology and skills of the parasitoid, a Xenomorph spawned by a [[dog]] displays a distinctly canine body structure, digitigrate legs, quadrupedal movement, and greatly enhanced speed compared to those spawned by Human hosts, which are typically plantigrade and often bipedal.
   
Xenomorphs are conscious of the effects of their acidic blood, and will use it to their advantage - to break out of human-constructed confinement, or as a weapon. They show some military tactics (such as retreating when overwhelmed), and can find ways to get around certain problems (such as pushing the red button to freeze a soldier in liquid nitrogen). They know that the darkness is their ally, and break lights to create cover.
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Even among those spawned exclusively from Humans, different Xenomorph hives can produce highly divergent individuals. Some are taller and lankier, with an almost erect posture. Others are shorter and bulkier, and move more quadrupedally. While most have smooth craniums, others have ridges, which may be attributed to their age (i.e. those which have more time to develop may end up with ridges) and/or caste (ridges being associated with Warriors, and smooth features with Drones).
   
===Anatomy===
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When it comes to their digits, there are at least three different patterns.
[[File:Alien_1986.png|thumb|left|320px|Warrior Alien]]
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*Some Xenomorphs have six fingers, with the index and middle fingers conjoined into one digit, ring and little fingers also conjoined, and thumbs on both sides.
A Xenomorph Warrior is equipped to be the perfect killing machine. They possesses an exoskeleton much like that of a [[wikipedia:Lobster|lobster]], impenetrable to everything but the most powerful human firearms (12-gauge shotguns, Pulse Rifles, and stanchion launchers are quite effective). Ash claims the creature's skin is made from 'protein polysaccharides', so this would imply a substance similar to [http://en.wikipedia.org/wiki/Chitin chitin]. He also says the creature replaces its surface cells with polarized silicon, which is a very inert, heat resistant, and flexible polymer. This allows these creatures great environmental resistance. However, they are vulnerable to sudden, massive changes in temperature, as shown in ''Alien 3'', when these creatures are destroyed by first immersion in molten lead and then sudden cooling with fire sprinklers, causing its silicon shell to shatter.
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*Others are shown with five fingers, with the second thumb missing.
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*A third phenotype has only four fingers, though the middle two appear to be a fusion of two digits.
   
Attached at the ends of both of their arms are a set of long fingers and shiny, black, and extremely sharp claws capable of slashing through almost anything within its grasp (as seen in ALIEN books, such as Book 2: ''Nightmare Asylum''). They have two pairs of finger-like digits and appears to have two opposable thumbs (on opposite sides of the hand) on each hand. Its tail is long, and can be used as a whip. Later movies show them to have ridges on top, and a serrated toxic tip at the end to lacerate enemies.
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On at least one occasion, Human-spawned Xenomorphs were observed to have a digitigrade, as opposed to plantigrade posture. However, it should be noted that these were spawned by a Queen grown from cells derived from a clone of Ellen Ripley, making their genetic heritage muddled at best.
   
They stand at around 7 feet tall, averaging in anywhere between 140&nbsp;kg and 180&nbsp;kg; although size may vary wildly depending on the host chosen, as seen for instance with the "[[Jock-Xenomorph]]". Their mouths is filled with sharp teeth, but their main killing device is the inner jaw that shoots out to penetrate the victim's brain.
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Some Xenomorphs have tails that are roughly the same length as the rest of their bodies, equipped with a small, almost surgical stinger-like barb on the end. This stinger can be, and has been, used to perforate victims, and may turn loose from the tail and remain lodged in the victim's body, not unlike a bee stinger. Conversely, other specimens have tails that are considerably longer, and armed with a large, knife-like blade at the tip and sometimes with ridges of spikes right before the blade, which may aid in swimming.
   
The inner jaw (also known as an "attack tongue") is a muscular appendage on the inside of the Xenomorph's mouth. All Xenomorphs have this trait, excluding the Newborn. It consists of a cord of muscle with a small but extremely deadly mouth-like appendage on the end. This attack tongue is able to punch through almost anything, from bone to [[Yautja|Predator]] armor.
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====Head====
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[[File:Xenomorph-AlienVsPredator2010videogame.jpg|thumb|250px|A close-up of a Xenomorph head, revealing what might be interpreted as an eye.]]
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The most notable feature of the Xenomorph species is the elongated, banana-shaped head. A potential explanation for this curious shape may be that the head may store muscles required to power the Xenomorph's inner mouth.
   
===Physical Abilities===
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In terms of eyesight, the Xenomorph appears to be entirely eyeless. However, there are features on its head which could represent eyes, which are usually hard-to-see due to the fact that they're small and the same black color as the skin.
The adult Xenomorph is a living weapon,(tail is used as weapon) noted for their ferocity and deadliness in any condition. Once fully matured, they have great physical strength and agility. They are masters of stealth; a favored method of acquiring prey is to wait in a dormant state until an appropriate victim strays near, and then drop down silently from behind or use its tail to impale whoever walks by. The prey is generally blind to the fact that a Xenomorph is present, due to its propensity to camouflage itself within its nest walls or the surrounding artificial environment given their bio-mechanical-like appearance. The Xenomorphs will also use their pitch black carapace to their advantage, lurking in the shadows whilst waiting for prey to stray too close.
 
   
Xenomorphs are shown to be able to take extreme amounts of physical damage that would kill any Earth life form. An example of this is the Queen in ''Aliens'' survived a multi ton exo-suit falling on her from over 30 feet. Xenomorphs are capable of surviving with limbs shot off as seen in AVP3 the game and ''Aliens''. Even stabbings and shots through the head (though total decapitation kills them) as seen in ''Alien vs Predator'' and its sequel are not guaranteed to kill Xenomorphs.
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Other proposed conjectures include that the eyes might be similar to a desert-burrowing lizard's eyes; meaning that they lay under a thin layer of skin, yet are deep enough that they are not visible from the outside. In that case, their eyes could be hidden behind their black carapace and they see through it, similar to a one sided mirror (except in this case no one can see in, but the Xenomorph can see out). Some species of Earth fish, such as the Barreleyes, see through a transparent layer of skin; it is possible Xenomorph vision is similar. Another idea is that their whole head might represent one big insect-like eye.
   
Adult Xenomorphs are quick and agile, and can clamber along ceilings and walls, a skill they exhibit freely whether they are evading others, attacking, or hunting. They can survive in extreme temperatures, are well-adapted to swimming, can respire in harsh atmospheres, and can survive in vacuum for indeterminate lengths of time. Their movement tends to be silent, and they do not radiate heat as their [[wikipedia:exoskeleton|exoskeletal]] temperature matches the [[wikipedia:Ambient temperature|ambient temperature]]. They also [[wikipedia:saliva|salivate]] profusely. This saliva is not acidic, though some Xenomorphs do have the ability to spit acid, which may come from their stomachs, a special gland somewhere in their throats, or acid pouches lining the head. This can be used to blind victims, much like a [[wikipedia:Spitting cobra|spitting cobra]].
+
Eyeless or not, it is widely assumed that a Xenomorph identifies enemies by sensing pheromones. This has never been explicitly confirmed nor denied, but a Drone will not kill a host that's already infected, so they must have some way of detecting the presence of the unborn parasite within.<ref>As seen in the movie ''Alien³'' and the book ''Aliens: DNA War''</ref>
   
The creatures possess no visible eyes; Giger mandated this in his original design, because he felt that it made the creatures much more frightening if one could not tell they were looking at them. In the ''Alien vs. Predator ''series, the game implies that the Xenomorph sees using its attack tongue, though this may be for gameplay purposes rather than actual speculation.<ref>Alien Quadrilogy Boxset: Alien Evolution</ref> In the original ''Alien'' film, the top of the creature's head was semi-transparent, with empty eye sockets of human appearance visible within. This element was dropped in later movies, but reused for the [[Predalien]] design, on the front portion of its skull.
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====Secondary jaws====
  +
The secondary jaws (also known as the inner mouth, double jaw, or maw) are another disturbing feature of the species. It's assumed that they're powered by extremely strong muscles inside the creature's elongated head, that enable it to be quickly launched and retracted, similar to the tongue of a chameleon. The albino Xenomorph Drone has a very long inner mouth that can secrete resin that's used to build the walls of their hives.
   
In ''Alien³'', a fish-eye lens (which creates a perspective similar to that of a peephole) was used to depict the Xenomorph's sight. Whether this can be considered sight or just a filmed representation of the creatures' sensory perception is unknown.
+
The inner mouth is typically the Xenomorph's close-combat weapon, as opposed to its long-range tail. The Xenomorph lashes it out of its outer mouth, and it destroys anything it hits, being able to put a hole in a thickened Yautja skull and still have enough momentum to plunge another hole through the back as it escapes. Yautja take them as souvenirs of their kills.
   
However, in the novelization of the movie ''Alien'', the creature is held mesmerized by a spinning green light for several minutes. In the 2010 ''Alien vs. Predator'' game, it is mentioned on one of the Marine audio tapes that Xenomorphs have vision.
+
The secondary jaw is powered by muscles, as seen when a Yautja rubs a part of the interior (resembling the gills of a crab), a feature that can be seen from the external midsection on each side of the head, ovular in shape. Muscles rub along here, letting the mouth be pushed out like a piston through the target the Xenomorph has acquired.
   
Due to the absence of clearly visible eyes, it is possible that the creature uses [[wikipedia:Animal echolocation|echolocation]] to see its environment, much like [[wikipedia:Bat|bats]]. It may be for this reason that Xenomorphs hiss almost constantly. Though it may have the ability to see through an unknown structure, as they evolved differently from life on Earth. Xenomorphs may be able to detect their 'prey' through electro-reception. This is the method sharks use to detect even the most hidden prey. Creatures with the electro-reception sense can detect the electromagnetic field all animals produce allowing them to detect the creature's heart beat. This would explain how Xenomorphs always know where the humans are. And, as depicted in the ''Aliens vs. Predator'' games, the Xenomorphs can also detect their prey using [[wikipedia:Pheromone|pheromones]].
+
The Yautja-spawned Xenomorph (a.k.a. "Predalien") has the ability to use its inner mouth to implant chestburster embryos directly into a host's throat, like a facehugger. Since that particular Predalien was also on her way to developing into a Queen, it's possible that all future-Queens have this ability.
   
Another theory is that the eyes of a Xenomorph are behind their black carapace and they see through it, similar to a one sided mirror (except in this case no one can see in, but the Xenomorph can see out). Some species of terrestrial fish such as the Barreleyes see through a transparent layer of skin; it is possible Xenomorph vision is similar.
+
====Dorsal spines====
  +
Along the back of most Xenomorphs' bodies are a series of appendages that appear to have no clearly-defined function. It's still in debate what they are used for, with theories ranging from sensory organs to communication organs, to breathing apparatus, to defensive mechanisms, to structures that dissipate heat, to storing substances their bodies need, or to provide structures to carry around the young, underdeveloped chestbursters, the eggs or the facehuggers or as a counter weight to keep them from falling over when running. None of these ideas has been confirmed or denied so far.
   
Xenomorphs can also produce a thick, strong [[wikipedia:Resin|resin]], which they use to build their hives and [[wikipedia:Cocoon (silk)|cocoon]] victims. Much like [[wikipedia:Termite|termites]], they mix their viscous saliva with solids. It shows amazing heat and moisture-retaining qualities.
+
One theory is that the four back appendages are used as a type of radar that the alien utilizes to see through extreme environments or detect movements. It is also said that the dorsal spines are used to secrete and possibly store the resin used to build their hives.
   
===Vulnerabilities===
+
It is interesting to note that Xenomorph Drones have been observed to bury themselves in the ground, yet their spines are still shown just breaking the surface<ref>''Alien vs. Predator'' Volume 1 comic</ref>, implying some use when connected to the environment. This may be either biological (breathing, heat exchange, etc.) or sensorial (detecting the vibrations of marines walking on the ground above).
Xenomorphs, in all stages of their life cycles, have been said to have vulnerabilities to heat, although this was only shown in a deleted scene from the ''Alien'' Special Edition DVD, in which Ripley searches for her missing shipmates in the bowels of what appears to be the engine/boiler room of the ''Nostromo''. It is also mentioned in the game ''AVP 3'' by a flamethrower-carrying marine: "''Buggers don't like fire. This'll flush 'em out''". In the ''Alien: Isolation'' (2014) game, the only way to effectively drive off the Alien is with the use of molotovs and the flamethrower, however this causes it no actual damage (the Alien is invincible for gameplay purposes), and simply causes it to flee in a fearful panic.
 
   
The only Xenomorph not vulnerable to fire is the [[Predalien]]. In the game ''Alien vs. Predator: Extinction'', it secretes a layer over their body. That layer cannot be ignited, though they are visibly pained by temperature extremes such as liquid nitrogen.
+
Other hypotheses include:
  +
* Perhaps the spines separate the dominant Xenomorphs from the weaker ones, for example, the smaller the spines, the weaker the Xenomorph.
  +
* The creatures might come from a mainly amphibious planet, and perhaps the spines are a mechanism to swim underwater faster to catch prey. They do not seem all that hydrodynamic, but it's possible to suppose the spines might be used for stability, like the dorsal fins of a [[dolphin]] (not that their shape seems very much efficient at that either).
  +
* The spines might be spiracles that take in and filter the air around them, while waste is expelled through the mouth. It is widely accepted that they do not have lungs, so this is possible, and yet implausible because Runners (a.k.a. dog-spawned Xenomorphs), don't have them. But it may be that the Runners have lungs.
  +
* The spines might be used as a defense mechanism, to repel enemies that try to sneak up on them from behind or above.
  +
* They might also be traits that the alien acquires by chance when developing inside the facehugger, putting the legs of the facehugger on the back. The chestburster does not develop directly from the facehugger (instead, the facehugger plants the egg/larva that will become the chestburster inside a host), but it's not impossible that it acquires genetic traits from it.
  +
* They might be used to blend in with the hive web when under attack.
  +
* The spines may be for chestbursters to latch onto, allowing the adult to bring them to a safer location.
  +
* If the alien uses echolocation to see its prey, these may be what they feel the vibrations from.
  +
* They may be used to carry unhatched eggs to a new location when the Queen dies, allowing them to still climb walls while on the move.
  +
* The spines may be used to distribute pheromones - to distinguish one from another, and from other hives.
  +
* The spines may allow a facehugger to hook their spider-like legs until a victim is near. The facehugger will let go of its crude form of transportation, find the victim, and proceed with the process of laying eggs.
  +
* The spines may also act as a counter balance, much like a [[cat]]'s tail, so that the Xenomorph does not fall forward when running. Though in truth, a cat does not require a tail to balance properly while running, it more so helps to balance upon thin surfaces like fences and the backs of chairs, and since the Xenomorph already has a long tail, this idea has little credence.
  +
* They may be used for breathing, as it's possible that the inner jaws serve only offensive purposes. This also makes sense if one considers that they may have come from a swamp-like planet, where they would lay in wait for prey to wander by. This would also explain the 'dome' over their eyes (assuming they have eyes), which may have functioned similarly to a camel's second eyelids: allowing the alien to see, while preventing stuff from getting in its eyes.
   
A rapid succession of extremes in both high and low temperatures apparently causes a [[wikipedia:Thermal shock|thermal shock]] effect on a Xenomorph's exoskeleton. Xenomorphs are capable of adapting themselves to cold environments with little discomfort. The alien queen is extremely vulnerable to fire, for unknown reasons.
+
The "Runner", a Xenomorph born from a dog or other quadrupedal host, is notable in that it doesn't have dorsal spines. This could be an adaptation to make its body more aerodynamic and thus more efficient for running.
   
Xenomorphs are shown to be both invulnerable and vulnerable to small firearms,
+
====Tail====
ranging from [[wikipedia:9 mm caliber|9mm]] to [[wikipedia:5.56x45mm NATO|5.56mm]]. This is seen in one scene in ''Aliens'' where Vasquez and Lt. Gorman find themselves trapped in the ventilation between advancing aliens coming from both directions, Gorman fires with his pistol on one of them with no effect at all, instead it looks like they bounce off (presumably from the head carapace). In an earlier scene, Vasquez holds an alien at gun point and fires her pistol at the head, which apparently goes through and the alien rattles away, obviously damaged. High-caliber firearms, with the explosive rounds of a [http://aliens.wikia.com/wiki/M41A_Pulse_Rifle M41A Pulse Rifle] may cause the creatures to detonate. High-energy beam weapons, such as the plasma weapons used by Yautja, appear to be the best way to kill the Xenomorphs, though pulse rifles appear to be the best way to repel large hordes of them since they can fire non-stop and are not prone to being destroyed like the plasma weapons.
+
It is accepted that the tail is an offensive weapon and little more. Though the creature can and will run on all four appendages, it often stands on its two hind legs so it can reach for its prey with its arms. While standing, it has also been seen to impale its victim with its tail, even to the point where it can raise a creature heavier than itself to eye level, possibly in preparation for a face-bite using the secondary jaws. This would clearly be impossible if the tail was needed for balance, as the already-shifting weight would be too awkward, causing the monster to fall.
   
They are not invulnerable to melee weapons, although such equipment is likely to be destroyed upon contact with their acid blood.
+
As a weapon, the tail is extremely efficient, as it is long enough to attack from great distance and can be used in a variety of ways; for example, a Xenomorph has been observed to use its tail to knock the legs out from under a Yautja before trying to stab it.
   
===Cocooning===
+
The tail can be used in stealth attacks, since it is flexible enough to attack from a variety of positions, and is hard to notice if it is behind the enemy, or if the area is rather dark. Even when the sharp point is cut off, the tail is still deadly, as the Xenomorph can use the damaged tail to spray its acid blood from the severed tip over a wide area. Xenomorphs are also capable of using their tails as blunt-force weapons, clubbing their enemies with the vicious tail spikes.
Cocooning is a trait used by Xenomorphs to reproduce quickly. A human, or any other creature, if dragged away, would have a cocoon of saliva and resin placed over them (their face left free), usually in an area where the Queen has produced a large quantity of eggs, so that the Facehuggers are able to latch onto them easily and deposit a Xenomorph larva in their chest. In a cut scene in ''Alien ''(included in the Special Edition), Ripley found two of her cocooned colleagues actually being turned into Xenomorph eggs. This suggests that Xenomorphs can convert humans into eggs when there is no queen, although this may have been scrapped as many other features of the Xenomorphs were in later movies (such as the transparent skulls and empty eye sockets). In the book, it's described how the drones are able to implant a fetus in up to four hosts, thereby creating enough drones and warriors to start a hive with.
 
   
Another feature of cocooning as seen in the game ''Aliens Vs. Predator 3'' is that the Xenomorph Number Six, after entering and cocooning its victims, can change its appearance, eventually becoming a queen itself. This rapid genetic regeneration is also another evolutionary trait of the Xenomorph to ensure its very survival as a species. In ''Alien vs. Predators: Extinction'' the praetorian acted as a princess of the hive who then became the queen. This stage is seen with Number Six. If this is so, then Hudson is correct with them being like bees. The Xenomorph Queen can lay specialized eggs that are bigger (like queen egg cells in bees which are bigger than drone cells) that upon hatching can carry on the species through making other hives after the new female cocoons into a queen, as seen with Number Six and the aliens of ''Aliens vs. Predators: Extinction''. If this is the case though, that a drone can become a queen when no queen is present, then cocooning is also a method of survival for the Xenomorph species.
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===Physical abilities===
  +
[[File:ClonedXenomorphs-swimming.jpg|thumb|left|300px|Xenomorphs are capable swimmers.]]
  +
The adult Xenomorph is a living weapon, noted for their ferocity and deadliness in any condition. Once fully matured, they have great physical strength and agility. They are masters of stealth; a favored method of acquiring prey is to wait in a dormant state until an appropriate victim strays near, and then drop down silently from behind or use their tail to impale whoever walks by. The prey is generally blind to the fact that a Xenomorph is present, due to its propensity to camouflage itself within its nest walls or the surrounding artificial environment, given their biomechanical-like appearance. The Xenomorphs will also use their pitch black carapace to their advantage, lurking in the shadows whilst waiting for prey to stray too close.
   
==Variations==
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Xenomorphs are shown to be able to take extreme amounts of physical damage that would kill any earthly life form. An example of this is a Queen that survived a multi-ton exo-suit falling on her from over 30 feet. Xenomorphs are capable of surviving with limbs shot off, stabbings and even shots through the head (though total decapitation kills them).
The Xenomorph has been portrayed in noticeably different ways throughout the film series. Much of this was due to the continuing advancements made in the field of [[wikipedia:Special effects|special effects]], technology, and techniques used to bring it to life.
 
   
It has also been shown, both on-screen and in the games based on the ''Alien'' series, that the Xenomorph's form is affected by its host, so that different species of hosts will create different varieties of Xenomorph. An example of this is seen in ''Alien³'', when a dog (an ox in the extended edition) spawns a Xenomorph with a distinct canine body structure, quadrupedal movement, and greatly enhanced speed.
+
Adult Xenomorphs are quick and agile, and can clamber along ceilings and walls: a skill they exhibit freely whether they are evading others, attacking, or hunting. They can survive in extreme temperatures, are well-adapted to swimming, can respire in harsh atmospheres, and can survive in vacuum for indeterminate lengths of time. Their movements tend to be silent, and they do not radiate heat as their exoskeletal temperature matches the ambient temperature. They also salivate profusely. This saliva is not acidic, though some Xenomorphs do have the ability to spit acid, which may come from their stomachs, a special gland somewhere in their throats, or acid pouches lining the head. This can be used to blind victims, much like a spitting cobra.
   
===Upper Body===
+
Due to the absence of clearly visible eyes, it is possible that the creature uses echolocation to see its environment, much like bats. It may be for this reason that Xenomorphs hiss almost constantly, though there is evidence that they can detect light and darkness as well. Xenomorphs may be able to find their prey through electro-reception. This is the method sharks use to detect even the most hidden prey. Creatures with the electro-reception sense can detect the electromagnetic field all animals produce, allowing them to locate their prey by its heart beats, even if the prey is immobile. This would explain how Xenomorphs always know where the Humans are. Furthermore, the Xenomorphs can also detect whether a potential host is already infected, likely by sensing pheromones.
In the original ''Alien'' film, and in the sequel ''Aliens'', Xenomorphs are depicted as tall, slender creatures with a roughly human [[wikipedia:biomechanics|biomechanical]] design. The chest area appears to be rib cage-like in design.
 
   
In later films, such as ''Alien: Resurrection'' and ''Alien vs. Predator'', they are depicted as being shorter and bulkier organisms, as well as being more quadrupedal, portrayed by either stuntmen in suits for close-ups, or [[wikipedia:Computer-generated imagery|computer-generated imagery]] for their full form.
+
Xenomorphs produce a thick, strong resin, which they use to build their hives and cocoon victims. Cocooning is a trait used by Xenomorphs to reproduce quickly. A Human, or any other creature, if dragged away, may have a cocoon of saliva and resin placed over them (their face left free), usually in an area where the Queen has produced a large quantity of eggs, so that the facehuggers are able to latch onto them easily and deposit a Xenomorph larva inside their chest. Much like termites, they mix their viscous saliva with solids. It shows amazing heat and moisture-retaining qualities.
   
In ''Aliens'', Xenomorphs are depicted as having ridges along their [[wikipedia:Cranium|cranium]], while in all other films they have smooth [[wikipedia:cowl|cowls]] covering their [[wikipedia:Skull|skulls]]. It was speculated in the ''Aliens'' bonus DVD that this was due to these Xenomorphs having had more time to mature, compared to the Xenomorphs in the other films.
+
===Vulnerabilities===
  +
Xenomorphs, in all stages of their life cycles, have been said to have vulnerabilities to heat. The use of molotovs and flamethrowers constitutes an effective technique to drive them off. The only Xenomorph not vulnerable to fire is the Predalien, which can secrete a layer over its body that cannot be ignited, although they are still visibly pained by temperature extremes, such as liquid nitrogen.
   
In the comics and various video games (''[[wikipedia:Alien vs. Predator: Extinction|Aliens vs. Predator: Extinction]]'', ''[[wikipedia:Alien vs. Predators (SNES)|Alien vs. Predator (SNES)]]'', ''[[wikipedia:Alien vs. Predators 2|Aliens vs. Predator 2]]''), this was depicted as one of the visual differences between the Xenomorph Drone and Warrior castes. The Drones (in this instance used to indicate a "worker" caste, instead of mating-capable males) have the smooth cowl while the Warriors display the ridges. The Drones and Warriors have different tasks: warriors defend the hive, and drones hunt potential hosts, while some live only to protect the queen, such as hive warriors or praetorians.
+
A rapid succession of extremes in both high and low temperatures apparently causes a thermal shock effect on a Xenomorph's exoskeleton. Xenomorphs are capable of adapting themselves to cold environments with little discomfort. However, the alien Queen is particularly vulnerable to fire, for unknown reasons.
   
In ''Alien'' and ''Alien³'', the Xenomorph has six fingers, with the index and middle fingers conjoined into one digit, ring and little fingers also conjoined, and thumbs on both sides. In ''Aliens'', the Xenomorphs are shown with five fingers, with the second thumb missing. In ''Alien: Resurrection'' and ''Alien vs. Predator'', the aliens have four fingers, though the middle two appear to be a fusion of two digits. No explanation is given in the films for the fluctuating number of digits, although the creature's well-known genetic plasticity probably accounts for that.
+
Depending on the circumstances, Xenomorphs are shown to be both invulnerable and vulnerable to small firearms, ranging from 9mm to 5.56mm. This is seen when Vasquez and Lt. Gorman find themselves trapped in the ventilation between advancing aliens coming from both directions. Gorman fires with his pistol on one of them with no effect at all, instead it looks like the ammunition bounces off (presumably from the head carapace). In another occasion, however, Vasquez holds an alien at gun point and fires her pistol at the head, which apparently goes through and the alien rattles away, obviously damaged. High-caliber firearms, with the explosive rounds of a M41A Pulse Rifle may cause the creatures to detonate. High-energy beam weapons, such as the plasma weapons used by Yautja, appear to be the best way to kill the Xenomorphs, though pulse rifles appear to be the best way to repel large hordes of them since they can fire non-stop and are not prone to being destroyed like the plasma weapons.
   
===Lower Body===
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Xenomorphs are not invulnerable to melee weapons, although such equipment is likely to be destroyed upon contact with their acidic blood.
In ''Alien'' and ''Aliens'', the Xenomorphs were [[wikipedia:Plantigrade|plantigrade]]. In ''Alien³'', the Xenomorph is [[wikipedia:Digitigrade|digitigrade]], owing to its [[wikipedia:Quadruped|quadrupedal]] host organism (a dog in the theatrical cut, an ox in the extended version).
 
   
''Alien: Resurrection'' saw a dramatic redesign from previously-encountered human-spawned breeds: the Xenomorphs that emerged from human hosts in this film walked on digitigrade hind legs in a manner that does not conform with the appearance of previously-seen members of the breed. This is complicated by the fact that the Xenomorphs of the film were spawned by a Queen grown from cells derived from a clone of Ripley, making their genetic heritage muddled at best.
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===Acidic blood===
  +
The body fluid of all Xenomorphs appears to be a highly concentrated acid. It is frequently referred to as "acid blood", although it isn't clear whether or not it's used to carry any nutrients through the body.
   
In ''Alien vs. Predator'', the Xenomorphs return to their roots as plantigrade organisms, though their legs are sleeker and more skeletal in appearance, due to the use of computer visuals and hydraulic puppetry, rather than costumes.
+
It is somewhat unlikely that this fluid carries oxygen for a few reasons: the first being that the Xenomorph has been known to survive in vacuums such as space (for short periods of time, at least). The second being that Bishop mentions that the fluid loses its acidity shortly after the creature's death due to oxidation<ref>''Aliens'', Director's Cut</ref>. On the other hand, this is plausibly unimportant as oxidation is a term in chemistry used for the loss of electrons rather than a reaction with oxygen. All acids are oxidized no matter what they react with, therefore this has no bearing on blood carrying oxygen.
   
Originally, the Xenomorph's tail was roughly the length of the rest of its body, with a small, almost surgical [[wikipedia:Stinger (organ)|stinger]]-like barb on the end; but from ''Alien³'' onward, the tail has extended in length and features a large, knife-like blade at the tip.
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The "acidic blood" is able to dissolve through almost everything except the Xenomorph's body. The creature itself apparently knows how corrosive its "blood" is, as one flicked it at a charging Yautja, and it has been used to escape cages (by killing a "brother"). Some specially-treated Yautja weapons can resist this acid, although how long exactly is unknown.
   
In ''Alien: Resurrection'' and ''Alien vs. Predator'', the tails have also supported a ridge of spikes right before the blade. This was introduced in ''Alien: Resurrection'' to help them swim convincingly, and was left intact in ''Alien vs. Predator''. The tail itself is shown to be of incredible length during ''[[wikipedia:Alien vs. Predator|Alien vs Predator]]'', measuring almost its full body length.
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It has been often theorized that the Xenomorph "blood" may serve no function other than defense, being a liquid stored under the creature's skin that causes great harm to whoever succeeds in harming the Xenomorph. It remains possible, though, that the acid serves some function in the alien's metabolism, perhaps even as an actual blood system analogue. One possibility is that it may be an extreme analogue of stomach acid, and likewise serves to digest food. In that case, the Xenomorph's digestive system would be spread like a circulatory system throughout its body: the acid is so powerful that anything it consumes is immediately dissolved and the remains distributed over its body, with the extremely resistant walls of the "acid vessels" somehow allowing nutrients to be absorbed.
   
The original shooting script for ''Aliens'' featured a scene in which Lieutenant Gorman was "stung" by a Xenomorph's stinger. He was not killed, merely stunned, and the barb remained lodged in his shoulder, having torn loose from the Xenomorph's tail much like a bee stinger. The novelization also included this scene, though the final cut of the movie does not. This attribute is used later on in various games.
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===Genetic adaptation===
  +
[[File:Alien_1992.png|thumb|right|300px|A "Runner", a Xenomorph formed in a quadrupedal host.]]
  +
Due to horizontal gene transfer during the gestation period, the Xenomorph also takes on some of the basic physical attributes of the host from which it was born, allowing the individual alien to adapt to the host's environment more efficiently.
   
===The Head===
+
Through experiments, it was discovered that the embryo attaches itself to a major artery of its host, to get nutrients as it grows. It is presumed that the DNA from the blood it acquires infuses itself with the embryo's DNA to make up for its lack of genetic structure.
The most notable feature of the Xenomorph species is the elongated, banana-shaped head. This aspect is both disturbing and terrifying, combining visual elements that are usually blocked by our conscious mind with others resembling vaguely human features.
 
   
It is widely assumed that it identifies enemies by sensing pheromones. This has never been explicitly confirmed nor denied, but a Drone will not kill a host body already infected (as seen in the movie ''Alien 3'' and the book ''Aliens: DNA War'').
+
It may take on a thicker, bipedal form with a darker exoskeleton if it comes from something that stands on two legs, such as a Human. When the host is a four-legged animal, it may take on a more slender, sleeker appearance, where it too moves as a quadruped, and has a more reddish/orange-colored exoskeleton. It may also take on some facial features of its host (such as mandibles when implanted in a Yautja). Predaliens (Xenomorphs spawned from Yautja hosts) have a yellow-green partial skin covering their exoskeletons.
   
There has been one detail on an alien's head that may be an eye being so small and the same black as the skin. It is hard to see if these are eyes or an implant on the skin (you can see them on the front cover of the ''Aliens vs Predator'' 2010 video game and very rarely as a predator in alien vision). Another idea is that their whole head is one big insect-like eye; in ''Alien 3'', a fish-eye lens represented the [[Runner]]'s sight, but it is unknown if this is really how it sees or simply artistic license.
+
Furthermore, it is conceivable that it derives some level of intellect from its host. The quadrupedal variant seems easier to trick than bipedal ones, and the Predalien appears to have a better understanding of weapons being used against it.
   
Other proposed conjectures include that the eyes are similar to a desert-burrowing lizard's eyes; meaning that they lay under a thin layer of skin, yet are deep enough that they are not visible from the outside. This is seemingly lent support by early models and toys of the Warrior Xenomorph while ''Alien'' was still the only existing movie in the timeline. These showed an actual, physical, humanoid skull built under the smooth carapace, with the smooth top working like a one-way visor.
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===Life cycle===
  +
====Egg====
  +
[[File:XenomorphEggs.png|thumb|left|300px|Xenomorph eggs.]]
  +
The Xenomorph is born in egg form, laid in place by the hive's Queen, through the use of a detachable ovipositor. The egg is thick and gelatinous, usually with several membranes attached to the outer layers. It can take nutrients from the ground to support the creature inside. The egg has vein-like structures running through it, showing that it is actually a living creature, sometimes known as an '''ovomorph'''.
   
Another potential explanation for this curious shape may be that the elognated head may store muscles required to power the Xenomorph's inner mouth.
+
The Xenomorph hatchling - called a facehugger - is protected by a thick fleshy layer at the top of the egg, where the "shell" peels open when the facehugger senses creatures nearby. The sense that detects suitable organisms has to be very specific in what it chooses to respond to. Perhaps this is why it takes so long to open: various sensory organs study the approaching organism. It seems to be capable of distinguishing synthetic life from organic life.
   
=== Dorsal Spines ===
+
Sometimes Xenomorph Queens can lay eggs that contain up to four facehuggers.
Along the back of most Xenomorphs' bodies are a series of appendages that appear to have no function. It's still in debate what they are used for, with theories ranging from sensory organs to communication organs, to breathing apparatus, to defensive mechanisms, to structures that dissipate heat, to storing substances their bodies need, or to provide structures to carry around the young, underdeveloped chestbusters, the eggs or the facehuggers or as a counter weight to keep them from falling over when running. None of these ideas has been confirmed or denied by official sources so far.
 
   
One theory is that the four back appendages are used as a type of radar that the alien uses to see through extreme environments or detect movements. However in the extended universe it is said that the dorsal spines are used to secrete and possibly store the resin used to build their hives.
+
====Facehugger====
  +
[[File:Alien facehugger.jpg|thumb|300px|A facehugger attached to Kane aboard the ''Nostromo''.]]
  +
After the egg opens, the '''facehugger''' emerges and seeks out a nearby life form, latching onto its face, wrapping its tail around its airway, and implanting the Xenomorph embryo(s) by sticking a tube down the host's throat. This is seen sometimes when a facehugger is contained in water or lunging at a soon to be host.
   
It is interesting to note that, in the ''Alien vs. Predator'' Volume 1 comic, Xenomorph Drones bury themselves in the ground, yet their spines are still shown just breaking the surface, implying some use when connected to the environment. This may be either biological (breathing, heat exchange, etc.) or sensory (detecting the vibrations of marines walking on the ground above).
+
It will coil its tail tighter around the airway to prevent premature removal, and an attempt to sever the fingers found that facehuggers possess the same acidic blood as an adult Xenomorph. The facehugger supplies oxygen to keep the host alive during the impregnating process. Once the embryo(s) has been implanted, the facehugger falls off, curls up, and dies.
   
Other hypotheses include:
+
Hosts usually fall into a short coma and wake up ravenously hungry. This can be explained as the embryo needing an immediate source of nutrients for its progression into the next stage of its life. Hours might pass between the host waking and their time of death. Yautja live the longest as a result of an extended incubation period. The reason for this is likely due to the genetic complexity of the host. The incubating chestburster requires more time for mitosis and cytokinesis due to the morphology of the Predalien.
* Perhaps the spines separate the dominant Xenomorphs from the weaker ones, for example, the smaller the spines, the weaker the Xenomorph.
 
* The creatures might come from a mainly amphibious planet, and perhaps the spines are a mechanism to swim underwater faster to catch prey. They do not seem all that hydrodynamic, but it's possible to suppose the spines might be used for stability, like the dorsal fins of a dolphin (not that their shape seems very much efficient at that either).
 
* The spines might be spiracles that take in and filter the air around them, while waste is expelled through the mouth. It is widely accepted that they do not have lungs, so this is possible, and yet implausible because Runners, or Dog Aliens, don't have them. But it may be that the Runners have lungs.
 
* The spines might be used as a defense mechanism, to repel enemies that try to sneak up on them from behind or above.
 
* They might also be traits that the alien acquires by chance when developing inside the [[facehugger]], putting legs of the facehugger on the back. The [[chestbuster]] does not develop directly from the facehugger (instead, the facehugger plants the egg/larva that will become the chestbuster inside a host), but it's not impossible that it acquires genetic traits from it.
 
* They might be used to blend in with the hive web when under attack.
 
* The spines may be for Chestbursters to latch onto, allowing the adult to bring them to a safer location.
 
* If the alien uses echolocation to see its prey, these may be what they feel the vibrations from.
 
* They may be used to carry unhatched eggs to a new location when the Queen dies giving them the ability to still climb walls while on the move.
 
* They might be used to create the hive somehow.
 
* The spines may be used to distribute pheromones - to distinguish one from another, and from other hives.
 
* The spines may act much like the [[Carrier Xenomorph]] form seen in ''Alien Vs. Predator: Extinction'', allowing a Facehugger to hook their spider-like legs until a victim is near. The Facehugger will let go of its crude form of transportation, find the victim, and proceed with the process of laying eggs.
 
* The spines may also act as a counter balance, much like a cat's tail, so that the Xenomorph does not fall forward when running. Though in truth, a cat does not require a tail to balance properly while running, it more so helps to balance upon thin surfaces like fences and the backs of chairs, so this theory has little credence.
 
* They may may be used to breath, as it's possible that the inner jaws serve only offensive purposes. This also makes sense if you consider that they may have come from a swamp-like planet, where they would lay in wait for prey to wander by. this would also explain the 'dome' over it's eyes, and may have functioned similarly to a camel's second eyelids:allowing it to see, while preventing stuff from getting in its eye.
 
   
===Secondary Jaws===
+
However, in some cases, the hosts will awake not gradually but suddenly - just in time to be conscious of the chestburster's push out into the world. Their state of normalcy will last only seconds or minutes.
The secondary jaws, also known as the inner mouth, double jaw, or maw, is another disturbing feature of the species. It's assumed that it's powered by extremely strong muscles inside the creature's head, that enable it to be quickly launched and retracted, similar to the tongue of a chameleon. (Although the albino xenomorph drone has a very long "inner mouth" that can secrete resin throughout their hive.)
 
   
It is the Xenomorph's close-combat weapon, as opposed to its long-range tail. The Xenomorph lashes it out of its mouth, and it destroys anything it hits, able to put a hole in a thickened Yautja skull and still have enough power to plunge another hole through the back as it escapes.
+
It's also proven that when a host awakens, there is some sort of a memory lapse in which they don't remember anything that has happened to them. This short-term memory loss is most likely a result of the temporary oxygen deprivation caused by the facehugger's tail, as it asphyxiates the host.
   
The secondary jaw is powered by muscles as seen in the first ''Alien vs. Predator'' movie when the predator rubs a part of the interior (resembling the gills of a crab) a feature that can be seen from the external midsection on each side of the head, ovular in shape. Muscles rub along here, letting the mouth be pushed out like a piston through the target the Xenomorph has acquired.
+
Different types of facehuggers are known to exist, including some highly abnormal variants. The '''royal facehugger''' will give rise to Queens or to members of the Praetorian caste, the latter which may be promoted to Queens later on. However, there's also a poorly-known caste of '''giant facehuggers''' which are also known as '''queen facehuggers''', but don't seem to be related to Queens directly. Unlike regular facehuggers, these giants don't seek to impregnate hosts, but merely protect the ovomorphs. They may use their legs and tail to immobilize potential hosts, allowing regular facehuggers to latch onto the victims' faces and impregnate them<ref>''Aliens: Terrordome'' mini-comic</ref>.
   
The Predalien has the ability to use its inner mouth to implant Chestburster embryos into a host's throat, like a Facehugger.
+
Another highly aberrant form is the '''Infectoid''' facehugger, which doesn't implant an embryo, but rather fuses itself to the host's body, transforming the host into an undead [[zombie]]-like being, linked to the aliens' hive mind<ref>''Aliens'' video game, 1990</ref>.
   
Yautja take them as souvenirs of their kill.
+
====Chestburster====
  +
[[File:Alien chestburster.jpg|thumb|left|300px|A chestburster]]
  +
After attaching itself to a vein and gestating in the chest cavity, Xenomorph infants - called '''chestbursters''' - push and chew through the host's chest, causing severe pain, blood loss, shock and death. The host's rib cage is cracked open, bones bent outward. No one has survived this process other than Emil Zorn, who was fitted with an artificial torso following this encounter. However, Ripley was cryogenically frozen after she was cloned, and then had it surgically removed. It was also revealed that high amounts of stress can actually make the chestburster more frantic. This causes it to push and chew through the chest at a faster pace, therefore emerging slightly earlier than normal. On one occasion, the chestburster erupted out of the head of a host Human instead of the chest.
   
===The Tail===
+
It is suggested that the removal of the chestburster would still lead to the death of the host due to the remaining alien tissue acting like a malignant tumor, in effect developing into a fatal cancerous growth.<ref>''Aliens: Colonial Marines''</ref>
It is accepted that the tail is an offensive weapon and little more. Though the creature can and will run on all four appendages, it often stands on its two hind legs so it can reach for its prey with its arms. While standing, it has also been seen to impale its victim with its tail, even to the point where it can raise a creature heavier than itself to eye level, possibly in preparation for a face-bite using the secondary jaws. This would clearly be impossible if the tail were needed for balance, as the already-shifting weight would be too awkward, causing the monster to fall.
 
   
As a weapon, the tail is extremely efficient, as it is long enough to attack from great distance and can be used in a variety of ways; for example, in ''Alien vs. Predator'', a Xenomorph used its tail to knock the legs out from under a Yautja before trying to stab it.
+
At this stage, the Xenomorph is small, limbless, and very vulnerable. Among other possibilities, its neck can be snapped. It needs to get to a safe area so it can reach its next life stage. It moves with its long tail, and can coil up and jump. It cannot climb on walls or ceilings, but despite these drawbacks it can traverse an area with astonishing speed.
   
The tail can be used in stealth attacks, since it is flexible enough to attack from a variety of positions, and is hard to notice if it is behind the enemy, or if the area is rather dark. Even when the sharp point is cut off, the tail is still deadly, as the Xenomorph can use the tail to spray its acid blood from the severed tip over a wide area. Xenomorphs are also capable of using their tails as blunt-force weapons, clubbing their enemies with the vicious tail spikes.
+
In some cases, they turn into a cocoon<ref>''Alien vs Predator: Extinction''</ref>, though this could be a subspecies. The common assumption is that the alien molts, grows legs, and develops much like a tadpole turning into a frog. Another common theory (the most accepted one) is that chestbursters shed their skin upon growing, as shown when Brett picks up a chestburster skin he found on the floor in an area the chestburster took shelter in.
   
===Acidic Blood===
+
At very rare times the chestburster emerges after the host has already died, which has been observed in an ox<ref>''Alien³'' extended version</ref>. Why the ox died after it was implanted is unknown; though the most likely reason would be due to a combination of the stress of implantation coupled with the poor health of the animal. It is seen to be riddled with parasites and presumably spent much of its life in the harsh environment of Fiorina "Fury" 161. Strangely, in this circumstance, the chestburster lived. This was also seen after the Empress killed a Predator and the chestburster survived.
The body fluid of all Xenomorphs appears to be a highly concentrated acid. It is frequently referred to as "acid blood", although it isn't clear whether or not it's used to carry any nutrients through the body.
 
   
It is somewhat unlikely that this fluid carries oxygen for a few reasons: the first being that the Xenomorph has been known to survive in vacuums such as space (for short periods of time, at least). The second being that, in the Director's Cut of ''Aliens'', Bishop mentions that the fluid loses its acidity shortly after the creature's death due to oxidation. On the other hand, this is plausibly unimportant as oxidation is a term in chemistry used for the loss of electrons rather than a reaction with oxygen. All acids are oxidized no matter what they react with, therefore this has no bearing on blood carrying oxygen.
+
In some cases, morphological traits acquired from the host may already be visible in the chestburster stage, for example: a chestburster born from a Yautja will already display the characteristic mandibles of the race. Some types of chestbursters already have legs when they emerge, including the royal chestburster and the "Runner".
   
The "acidic blood" is able to dissolve through almost everything except the Xenomorph's body, as shown in ''Alien vs. Predator''. It apparently knows how corrosive its "blood" is, as one flicked it at a charging [[Predator]], and it has been used to escape cages (by killing a "brother"). Some specially-treated Predator weapons can resist this acid, although how long exactly is unknown. "On the pH scale, it would probably rank at a devastating negative four or lower", a previous author claimed.
+
A variation of this stage is known as the '''bellyburster''', which erupts from the host's abdomen, rather than chest. These seem to be formed when the host is a pregnant female, and the alien embryo develops inside her womb, presumably feeding on the fetus. A Predalien has been observed to impregnate several hosts with multiple embryos each, which later gave rise to bellybursters. Since multiple bellybursters can develop inside a single host's womb, they can be used as an efficient way for a young future-Queen to establish a new hive faster.
   
This is theoretically possible, despite the fact that pH is the minus logarithm of the free H-ions' concentration. To put this this into perspective water has a neutral pH of 7 and our stomach acid has a pH of 1, which would lie at the very bottom of the 1 to 14 scale. Attempts to discredit such a claim are challenged indirectly by Chemists who have found that mixing antimony pentafluoride with hydrofluoric acid can produce a solution with a pH of -31.This therefore would render it 100,000 billion, billion, billion times more potent than stomach acid. It should be noted however that this acid is basically formed by mixing two incredibly strong acids together in the first place, which interact to become even more acidic. Though former theories have in fact stated that two potent chemicals (with perhaps some biological catalyst) may mix to create the acidic blood seen. Perhaps the strongest 'solo' acid would be the boron-based carborane with a pH of -18. Yet due to the structure of carborane, the H+ ions, which create the phenomenon known as acidity, are shared so efficiently between molecules that it would have no corrosive effects at all. Hence despite challenges It would appear even that which is known on earth certainly leaves scope for the incredible properties of the aliens acidic blood. It may also go without saying that different environments in other worlds could evolve "acid blood" that could also carry whatever nutrients that the Xenomorph needs.
+
====Adult====
  +
Little is known about the transformation that occurs between the chestburster and '''adult''' phases. As already stated, the Xenomorph appears to molt before reaching maturity. Maturity is reached in a few hours, and involves a dozen-fold increase in mass, which would presumably require some form of nourishment. In the ''Nostromo'', Ripley comes across a food locker that had been raided, apparently by the Xenomorph to get food.<ref>''Alien'' novelization by Alan Dean Foster</ref>
   
It has been often theorized that the Xenomorph "blood" may serve no function other than defense, being a liquid stored under the creature's skin that causes great harm to whoever succeeds in harming the Xenomorph. It remains possible, though, that the acid serves some function in the alien's metabolism, perhaps even as an actual blood system analogue. One possibility is that it may be an extreme analogue of our stomach acid, and likewise serves to digest food. In that case, the Xenomorph digestive system would be spread like a circulatory system throughout its body: the acid is so powerful that anything it consumes is immediately dissolved and the remains distributed over its body, with the extremely resistant walls of the "acid vessels" somehow allowing nutrients to be absorbed.
+
When the first Drone encountered on record was born in the ''Nostromo'', it had a smooth, long head, and an upright-standing body. It had no visible eyes, a tail, and strange spines protruding from its back. However, many years later on LV-426, the same species was found, but they looked slightly different. The head was no longer smooth, but ridged. One theory is that the smooth-headed Xenomorph was a Drone, and the ridge-headed Xenomorphs were Warriors. This is supported by the fact that the alien aboard the ''Nostromo'' built a nest, which only Drones can do since it is part of their job in the colony.
   
===Genetic Adaptation===
+
Another widely accepted idea, however, is age - the Xenomorphs found on LV-426 were more than a few days old, while all of the others encountered were less than a day old. On the other hand, some hives seem to have a distinct coloration for each caste, in which the Drones are black and the Warriors are a very dark blue; the color difference indicating that age is not a factor.
[[File:Alien_1992.png|thumb|320px|A "[[Runner]]", a Xenomorph formed in a quadrupedal host.]]
 
Due to [http://en.wikipedia.org/wiki/Horizontal_gene_transfer horizontal gene transfer] during the gestation period, the Xenomorph also takes on some of the basic physical attributes of the host from which it was born, allowing the individual alien to adapt to the host's environment.
 
   
Through experiments, it was discovered that the embryo attaches itself to a major artery of its host, to get nutrients as it grows. It is presumed that the DNA from the blood it acquires infuses itself with the embryo's DNA to make up for its lack of genetic structure.
+
Another variation was encountered on an expedition to Antarctica. These Warriors were less humanoid and sometimes walked on all fours. Their tails were longer, with a large, curved barb at the end. The head was smooth but much shorter than normal. It is important to note, however, that this particular Xenomorph hive was grown by the Predators, who introduced a hormone with unknown effects into the Queen's system.
   
It may take on a thicker, bipedal form with a darker exoskeleton if it comes from something that stands on two legs, such as a human. In the movie ''Alien 3'', it came from a four-legged animal, and thus took on a more slender, sleeker appearance where it too moves as a quadruped, with a more reddish/orange exoskeleton. It may also take on some facial features of its host (such as mandibles when implanted in a [[Yautja]]). Predaliens (Yautja-Xenomorph hybrid offspring) have a yellow-green partial skin covering their exoskeletons.
+
As the Xenomorph has been shown to be an extremely adaptable organism, which lays hundreds of eggs, develops quickly and is highly efficient at altering its own genome to better fit the environment (absorbing traits from its hosts), it's very likely that some phenotype variations are simply the result of genetic variation between different populations, which evolve very fast.
   
Furthermore, it is conceivable that it derives some level of intellect from its host. The quadrupedal variant in ''Alien 3'' seemed easier to trick than previous bipedal versions and the Predalien appeared to have a better understanding of weapons being used against it.
+
===Host-based variations===
  +
====Predalien====
  +
[[File:PredAlien_(1).jpg|thumb|300px|A Xenomorph formed from a [[Yautja]] host.]]
  +
Like normal Xenomorphs, a '''Predalien''' gains traits from its host. From the chestburster stage, it is noticeably different from other Xenomorphs. It is a somewhat dark shade of green with external mandibles, due to its Predator (Yautja) heritage.
   
==Life Cycle==
+
They lack speed, and their acid blood is not as deadly as a normal Xenomorph's. If a Predalien is part of a hive that has no Queen, it may serve as Queen due to its reproductive capabilities - its mandibles hold the host's head in place while its inner mouth implants one or more Xenomorph embryos into the host's throat, similar to the function of a facehugger. Up to four Xenomorph embryos may be planted in a host, if the Predalien needs to build up numbers quickly. It also possesses higher intelligence than normal Xenomorphs. Though an accepted breed among the Xenomorphs, the Yautja believe this kind to be abominations that must be vanquished by any means necessary.
===Egg===
 
The Xenomorph is born in egg form, laid in place by the hive's Queen, through the use of a detachable [[Wikipedia:Ovipositor|ovipositor]]. The egg is thick and gelatinous, usually with several membranes attached to the outer layers. It can take nutrients from the ground to support the creature inside. The egg has vein-like structures running through it, hinting that it is actually a living creature (sometimes known as an [[Ovomorph]]).
 
   
The Xenomorph hatchling - called a Facehugger - is protected by a thick fleshy layer at the top of the egg, where the "shell" peels open when the Facehugger senses creatures nearby. The sense that detects nearby, suitable organisms has to be very specific in what it chooses to respond to. Perhaps this is why it takes so long to open: various sensory organs study the approaching organism.
+
====Runner====
  +
[[File:Runner2.jpg|thumb|left|250px|A Xenomorph formed from a quadrupedal host.]]
  +
'''Runners''', a.k.a. "Dog Aliens", are produced from a facehugger jumping onto a dog or other quadrupedal species, such as an ox. They act as scouts for the hive, likely due to their quadrupedal and fast nature.
   
In the first movie, it appeared they could sense when another creature crossed into some form of mist covering their nursery area. It's a widely accepted hypothesis that this was a containment field to keep the eggs dormant (this same mist has been used as such in ''Aliens Vs. Predator 2'' video game), put in place by a [[Space Jockey]]. When this mist was broken, the Facehuggers appeared to be alerted, and went on the search for the host.
+
Runners are tinged a noticeable brown and run on four legs like the host they hailed from. However, they will walk and stand on two legs sometimes. On their back, there are no dorsal tubes, likely for better head mobility. Unlike most Aliens, they are digitigrade (i.e. they walk on their toes). Their chestbursters are not as larval as the other aliens, but rather a smaller, pale version of themselves.
   
===Facehugger===
+
The Runner is all about speed and agility, perhaps one of the fastest castes of Xenomorph ever encountered. It stalks its prey much like a lion or tiger, waiting for an unfortunate victim to come about and killing them outright, rather than cocooning them in a nest like others would. They are known to use stealth, just like their siblings. Although not as strong as other castes, Runners are still strong enough to lift a full grown Human. Like other Xenomorphs, they're also known to attack the head of their prey with their pharyngeal jawed tongues, and are capable of spitting acid.
[[Image:Alien facehugger.jpg|thumb|300px|A facehugger attached to Kane aboard the ''Nostromo''.]]
 
   
After the egg opens, the '''[[Facehugger]]''' emerges and seeks out a nearby life form, latching onto its face, wrapping its tail around its airway, and implanting the Xenomorph embryo(s) by sticking a tube down the host's throat. It is seen sometimes when a facehugger is contained in water or lunging at a soon to be host.
+
Runners are shown to be more animalistic in nature and are not the sharpest caste in the hive. They do have some intelligence, but not as much as their bipedal counterparts. The Runner on Fury 161 utilized hit and kill tactics, rather than capturing creatures and cocooning them in an established nest. They are smart enough to not harm any members of their own kind, especially hosts impregnated with larval Queens. This was seen when Ellen Ripley was in the medical bay of the Fury 161 penal colony. After the Dragon killed Chief Medical Officer Jonathon Clemens, it quickly turned to Ripley, who was horrified of the creature and despite its intimidating moves towards her, left her completely unscathed. It even tried to protect Ripley from Leonard Dillon who was trying to get her away from it while it was trapped in a corner.
   
It will coil its tail tighter around the airway to prevent premature removal, and an attempt to sever the fingers found that Facehuggers possess the same acidic blood as a Xenomorph. The Facehugger supplies oxygen to keep the host alive during the impregnating process. Once the embryo(s) has been implanted, the Facehugger falls off, curls up, and dies.
+
Conversely, this same individual has also demonstrated a desire for revenge, even against those carrying unborn Xenomorphs. This was seen after it was drowned in hot lead and managed to survive. This led to the creature chasing after Ripley until she dowsed it in water from the sprinklers, causing it to explode via thermal shock.
   
Hosts usually fall into a short coma and wake up ravenously hungry. This can be explained as the embryo needing an immediate source of nutrients needed for its progression into the next stage of its life. Hours might pass between the host waking and their time of death. Predators live the longest as a result of an extended incubation period. The reason for this is likely due to the genetic complexity of the host. The incubating chestburster requires more time for [http://en.wikipedia.org/wiki/Mitosis mitosis] and [http://en.wikipedia.org/wiki/Cytokinesis cytokinesis] due to the [http://en.wikipedia.org/wiki/Morphology_(biology) morphology] of the Predalien.
+
====Tarkatan====
  +
[[File:Audit2.png|thumb|200px]]
  +
The '''Tarkatan Xenomorph''' is a strain of Xenomorph born from a [[Tarkata]]n host. Although, by genetic identification, this strain is identified as "Tarkatan", this type is only one of three variations of this specific strain.<ref>''Mortal Kombat X''</ref>
   
However, in some cases, the hosts will awake not gradually but suddenly - just in time to be conscious of the Chestburster's push out into the world. Their state of normalcy will last only seconds or minutes.
+
This Xenomorph strain appears to be a bit more bulky and muscular than their wiry, lanky Human-spawned siblings. It is black, like them, but has a shorter head and a more impressive set of teeth, like its host. The Xenomorph also has arm blades, a trait taken from its host, though its blades are segmented and hooked at the ends. The primary difference between the three variations of the Tarkatan strain is the head. The primary variation's head is similar to the ridged head of the Warrior. The Acid variation is smooth-lined like the Drone caste, while the Konjurer variation's head bears a close resemblance to the larger crest of a Praetorian.
   
It was also proven - in the movie ''Alien'' that when a host awakens, there is some sort of a memory lapse before the Facehugger actually attaches itself to the host; they don't remember anything that has happened to them. This short-term memory loss is most likely a result of the temporary oxygen deprivation caused by the Facehugger's tail, as it asphyxiates the host.
+
The Tarkatan Xenomorph appears to be able to adhere itself to surfaces like most of its species. Its most obvious and striking feature is its arm blades, which bear a resemblance to some Yautja weaponry. The Acidic variation of this strain is able to spew blood out from its body, while the Konjurer variation has the ability to summon Drones and facehugger "traps" on the battlefield.
   
===Chestburster===
+
===Subspecies and other morphs===
[[File:Alien chestburster.jpg|thumb|left|300px|A Chestburster]]
+
Numerous types of Xenomorphs have been recorded which aren't the product of gene transference from a host. As a widespread species with fast reproduction, the emergence of a number of subspecies and mutations is to be expected; although some of them haven't evolved naturally, but were intentionally engineered by scientists.
After attaching itself to a vein and gestating in the chest cavity, Xenomorph infants - called [[Chestburster]]s - push and chew through the host's chest, causing severe pain, blood loss, shock and death. The host's rib cage is cracked open, bones bent outward. No one has survived this process. However, Ripley, in the film ''Alien: Resurrection,'' was cryogenically frozen after she was cloned, and then had it surgically removed. It was also revealed in the 2010 ''Aliens v.s. Predator'' game that high amounts of stress can actually make the Chestburster more frantic. This causes it to push and chew through the chest at a faster pace, therefore emerging slightly earlier than is normal. On one occasion the Chestburster erupted out the head of a host human instead of the chest.
+
*'''[[Bodyburster]]''': A rare neotenic variant that never matures past the chestburster stage, resulting in a giant worm-like creature.
  +
*'''[[K-Series]]''': Also known as "Yellow Xenomorphs", due to the coloration of their skin. Created by Dr. Samuel Kadinski, they fought against the original Xenomorphs, but failed to defeat them.
  +
*'''[[Neomorph]]''': A pale-white variant found on the mysterious planet where the android David conducted his research from 2094 to 2104. The life cycle of this subspecies is different, involving airborne spores rather than eggs and no facehugger stage.
  +
*'''[[Red Xenomorph]]''': A naturally-occurring mutation; easily-recognizable for their red skin. A Red Queen Mother and her warriors tried to take over Xenomorph Prime, waging war against the black Xenomorphs. The "civil war" ended with the defeat of the red-skinned "rebels".
  +
*'''Tusked Xenomorph''': Employed as "hunting dogs" by some Yautja clans, similarly to the [[Predator Hound]]s and [[Hell-hound]]s. They look similar to other Xenomorphs, but possess a pair of tusks, already present in the chestburster stage. They've been observed to be born from Human hosts, ruling out the possibility of being simply bred from a tusked species.
   
It is suggested in ''Aliens: Colonial Marines ''that removal of the Chestburster would still lead to the death of the host due to the remaining Alien tissue acting like a malignant tumor, in effect developing into a fatal cancerous growth.
+
==Culture and society==
  +
The Xenomorphs have a caste system similar to that of bees and ants. A major difference is that their caste system is far more complex.
   
At this stage, the Xenomorph is small, limbless, and very vulnerable. Among other possibilities, its neck can be snapped. It needs to get to a safe area so it can reach its next life stage. It moves with its long tail, and can coil up and jump. It cannot climb on walls or ceilings, but despite these drawbacks it can traverse an area with astonishing speed.
+
It's believed that the Drones (in this instance used to indicate a "worker" caste, instead of mating-capable males) have the smooth cowl while the Warriors display the ridges. The Drones and Warriors have different tasks: Warriors defend the hive, and Drones hunt potential hosts, while some live only to protect the Queen, such as Hive-Warriors or Praetorians.
   
In ''Alien vs Predator: Extinction'', they turn into a cocoon (though this could be a subspecies). The common assumption is that the alien molts, grows legs, and develops much like a tadpole turning into a frog. Another common theory (the most accepted one) is that Chestbursters shed their skin upon growing, as shown when Brett picks up a Chestburster skin he found on the floor in an area the Chestburster took shelter in.
+
===Drone===
  +
The basis of any Xenomorph hive; the '''Drones''' are very much like worker bees or ants. Their main tasks are to keep the hive in good condition. Also, they seem to have the job of creating their nests with their own secretions.
   
At very rare times the Chestburster emerges after the host has already died, as seen in ''Alien 3'' extended version. Why the ox died after it was implanted is unknown; though the most likely reason would be due to a combination of the stress of implantation coupled with the poor health of the animal. It is seen to be riddled with parasites and presumably spent much of its life in the harsh environment of Fiorina "Fury" 161. Strangely, in this circumstance, the Chestburster lived. This was also seen in ''Alien vs Predator'': after the Empress killed the Predator, the Chestburster survived.
+
They average in size at about 6–7 feet tall (~ 1.8 to 2.1 meters) standing on hind legs, and about 14–15 feet long (~ 4.2 to 4.6 meters), tail included. They have the basic body build of the Warrior, except that their dome is completely smooth, whereas the Warrior's dome is typically more ridged. Drones are smaller and somewhat more delicate than the Warriors, not considered quite as dangerous by Yautja standards, but striking fear into the heart of any Human.
   
===Adult===
+
Like all of their brethren, they have acidic body fluids, but only the Drone can spit this secretion onto prey over a short distance. Drones have an organ in their bodies that releases a sticky fluid that they can spit out of their mouth onto any surface. It can be used to harvest cocooned hosts for the Queen's facehuggers.
Little is known about the transformation that occurs between the Chestburster and Adult phases.
 
   
The Xenomorph appears to [[wikipedia:Moult| molt]] before reaching maturity. Maturity is reached in a few hours, and involves a dozen-fold increase in mass, which would presumably require some form of nourishment. In the novelization of the movie ''Alien'', Ripley comes across a food locker that had been raided, apparently by the Xenomorph to get food. Whether or not this was nourishment to grow was not specified. In the video game ''Alien Vs. Predator 2'', one of the Alien missions requires the player to find a source of food in order for the Chestburster to advance to its Drone phase. At the end of the level, a short cut-scene indicates that the Chestburster consumes a house cat in a carrier. The scene does not show what happens during the change in the life cycle.
+
===Warrior===
  +
Warrior Xenomorphs - commonly known as simply '''Warriors''' - are the soldiers and protectors of the hive. They are all children of the hive's Queen, bigger and stronger than the Drones. The Drones are less deadly and somewhat less intimidating.
   
There must be a common nutrient found in the Black Goo in Prometheus and all other types of food that would nourish the developing Xenomorph otherwise like the Xenomorph being able to determine that Ripley had a Queen inside of her all Xenomorphs would be able to determine which foods contained the same nutrients found in the Black Goo.
+
Warriors average in size at about 8 feet tall (~ 2.4 meters) standing on hind legs, and about 14–16 feet long (~ 4.2 to 4.9 meters), tail included. In most cases, the Warrior looks the same as a Drone, except that the dome on top of the head is generally ridged.
   
In ''Alien'', Brett found a shed skin resembling a Chestburster in the area of the ''Nostromo'' it had taken shelter in, implying that it sheds its skin before moving onto its next form. This has also been shown in the expanded universe.
+
They may evolve into Praetorians, which may serve as the Queen's personal guard and potential successors. Typically, there are four of them at any given time. However, when the Queen wishes to watch them battle for her attention or increase protection in preparation for an attack on the hive, she will release pheromones which cause four additional Warriors to evolve into Praetorians.
   
When the first Drone encountered on record was born on the ''Nostromo'', it had a smooth, long head, and an upright-standing body. It had no eyes, a tail, and strange spines protruding from its back.
+
===Praetorian===
  +
'''Praetorians''' ("Royal Guards"), are bigger and stronger than the Warriors and are seen to have a developing crown. Their primary role within the hive is to guard key locations of importance or interest, and, if nothing else, to protect the Queen herself. Most Praetorians can be found very close to the Queen's chambers. The physical features of the Praetorian are pristine and very similar to the Queen's: it has a crown-like head crest, large size, and great strength.
   
However, many years later on LV-426, the same warriors were found, but they looked slightly different. The head was no longer smooth, but ridged. One theory is that the smooth-headed Xenomorph was a Drone, and the ridge-headed Xenomorphs were Warriors (The Xenomorph in the first movie built a nest, which only Drones can do since it is their job in the colony).
+
The Praetorian is said to be created by special eggs and facehuggers known as a royal facehugger (these are generally larger and a darker color than normal facehuggers), which carries a genetic code known as the Royal Jelly Line, which is passed from the Queen herself to the facehugger and embryo. However, there are cases in which the Praetorians evolve from the Warrior caste. The Queen selects a Warrior to become a Praetorian, and the Warrior is then attacked by fellow Xenomorphs from the same hive and banished. The Warrior must survive on its own for a long period of time. It grows and sheds, becoming approximately fifteen feet tall (~ 4.6 meters) and gaining its head crest. It returns to the hive as a worthy guard to the Queen.
   
The most widely accepted idea, however, is age - the Xenomorphs found on LV-426 were more than a few days old, where all of the others encountered were less than a day old. On the other hand, the ''Alien vs Predator'' game has shown that the Drones are black (like in the movies), but the Warriors are a very dark blue, the color difference indicating that age is not a factor.
+
Besides their guard duties, Praetorians may also act as the "princesses", or immature Queens of the hive, who can be promoted to Queens.<ref>''Alien vs. Predators: Extinction''</ref> The Xenomorph known as "Number Six" started out as a Warrior and demonstrated the ability to mature into a Praetorian and later a Queen.<ref>''Aliens Vs. Predator 3'' video game</ref> This rapid alteration is another evolutionary trait of the Xenomorph to ensure its very survival as a species. The Xenomorph Queen can lay specialized eggs that are bigger (like Queen egg cells in bees which are bigger than Drone cells), that upon hatching can carry on the species through making other hives after the new female cocoons into a Queen.
   
Another variation is the Dog or Runner Xenomorph, called so because of its dog-like stance (standing and moving on all fours) and higher speed. Its host was a dog, rather than a human.
+
Some varying reports of Praetorians with massive shield-like growths on their forearms have been seen.
   
Another variation was encountered on an expedition to Antarctica. These warriors were less humanoid and sometimes walked on all fours. Their tails were longer, with a large, curved barb at the end. The head was smooth but much shorter than normal. It is important to note, however, that this particular Xenomorph hive was grown by the [[Predator]]s, who introduced a hormone with unknown effects into the Queen's system.
+
===Queen===
  +
[[File:Anguish.jpg|thumb|300px|A Queen alien, attached to her ovipositor.]]
  +
The Xenomorph '''Queen''' is the largest and most intelligent Xenomorph and can grow incredibly large, up to 100 feet tall (~ 30.5 meters) if given time. She lays many eggs that hatch to become the first stage of Xenomorph. It is unclear whether the Queen engages in combat outside of protecting her hive. The Queen is usually nestled deep within the hive, protected by Praetorian guards.
   
As the Xenomorph has been shown to be an extremely adaptable organism, which lays hundreds of eggs, develops quickly and is highly efficient at altering its own genome to better fit the environment (absorbing traits from its hosts), it's very likely that some phenotype variations are simply the result of genetic variation between different populations, which evolve very fast.
+
She has been known to display some logic-based intelligence, primarily in using simple Human technology such as lifts. She is the most dangerous of the hive, displaying extreme aggression and using her intelligence to devastating effect.
   
==Xenomorph Caste System==
+
When attached to her egg sac (ovipositor), she is immobile and vulnerable to attack. When she removes herself from it, however, she can move surprisingly fast. She attacks with her four clawed arms, as well as her long, bladed tail. She has also been shown to use her main and inner jaws in combat.
The Xenomorphs have a caste system similar to those of bees and ants. A major difference is that their caste system is far more complex.
 
   
===Drone===
+
Interestingly enough, it seems that the size of Queens varies. In one occasion, the Queen was shown to be maybe only twice the size of a Drone (this also may be due to her being so relatively young). In others, she is shown to be considerably larger - three or four times the size of a Drone. This could be explained in a similar fashion to an older Drone's ridged head, as the Queen in question was very old: although kept in a dormant state for long periods of time, she could have been alive for several millennia. Alternatively, she could have been an Empress. Queens usually stand around 15 to 20 feet tall on average (~ 4.6 to 6.1 meters).
The basis of any Xenomorph hive; the Drones are very much like worker bees or ants. Their main tasks are to keep the hive in good condition. Also, they seem to have the job of creating their nests with their own secretions.
 
   
They average in size at about 6–7 feet tall standing on hind legs, and about 14–15 feet long, tail included. They have the basic body build of the Warrior, except that their dome is completely smooth, whereas the Warrior's dome is more ridged. Drones are smaller and somewhat more delicate than the Warriors, not considered quite as dangerous by Yautja standards, but striking fear into the heart of any human.
+
As stated, Queens are created through royal facehuggers which produce Praetorians, or immature Queens. When a Queen dies or abandons a hive, a Praetorian may fully develop into a new Queen and take her mother's place. Whereas normal embryos adopt characteristics from their host, the royal facehugger's does not. The royal facehugger carries within it the Royal Jelly Line, which is a genetic code passed down from the Queen Xenomorph to her chosen offspring. The embryo is more or less a genetic copy of its mother and as such will not adopt the characteristics of the host, but will retain the physical characteristics of the Xenomorph Queen. Regardless of host, the Praetorian will appear nearly exactly the same as its mother when it fully develops into a new Queen. Because of this, it's often speculated that the Queen is the only "pure blooded" Xenomorph variety.
   
Like all of their brethren, they have acidic body fluids, but only the Drone can spit this secretion onto prey over a short distance.
+
===Empress===
  +
[[File:65920.jpeg|thumb|left|300px|Dr. Eisenberg stands in the guard of the alleged Empress]]
  +
There is mention of a Xenomorph '''Empress''' as well. Dr. Eisenberg might have merely used the term "Empress" to refer to the Queen. However, the Empress is bigger than the average Queen, and might also represent a distinct caste.
   
Drones have an organ in their body that releases a sticky fluid that they can spit out of their mouth onto any surface. It can be used to harvest hosts for the Queen's Facehuggers.
+
Although very similar to a regular Queen, the Empress's main duty is to establish order on a planet with multiple hives. The only known differences between the two are their size: the Empress is substantially taller than a Queen, standing anywhere from 20 to 25 feet tall (~ 6.1 to 7.6 meters); and the fact that an Empress' crown has five points instead of the traditional three. It is possible that an Empress is simply the oldest Queen on a planet, and the physical differences are the result of aging.
   
===Warrior===
+
It is also mentioned that after a hive grows to around 2,000 members, the younger Queens set out to establish new hives, and that if the Empress was to die, it would cause the younger Queens to fight over the new hive ruler. It's most likely that an "Empress" Xenomorph is merely a Queen that has dominated the other Queens in a hive. This would make the title "Empress" just that: a title.
Warrior Xenomorphs - commonly known as simply 'Warriors' - are the soldiers and protectors of the hive. They are all children of the hive's Queen, bigger and stronger than the Drones. The Drones are less deadly and somewhat less intimidating.
 
   
Warriors average in size at about 8 feet tall standing on hind legs, and about 14–16 feet long, tail included. In most cases, the Warrior looks the same as a Drone, except that the dome on top of the head is completely ridged.
+
Above the rank of Empress there is the '''Queen Mother''': the single supreme ruler of all Xenomorph hives on all conquered planets; which resides on Xenomorph Prime, accompanied by a personal guard of Queen-sized Praetorians known as '''Palatines'''.
   
They evolve into Praetorians, which serve as the Queen's consorts. Typically, there are four of them at any given time. However, when the Queen wishes to watch them battle for her attention or increase protection in preparation for an attack on the hive, she will release pheromones which cause four additional Warriors to evolve into Praetorians.
+
===Other castes===
  +
Other Xenomorph castes are rarely seen, and it's possible that not all hives have them, and/or that they prefer to stay hidden for the most part, and avoid venturing out of the hive or facing intruders.
   
===Praetorian (Royal Guard)===
+
One documented caste are the '''Workers''', a.k.a. Weavers or "Albino Drones", due to their white coloration. These Xenomorphs are considerably smaller than regular Drones, standing between 4 and 6 feet (~ 1.2 to 1.8 meters), and are usually not confrontational. More-so than any other caste, they're primarily concerned with the maintenance and expansion of the hive's structure, and may also tend to the Queen. They're most notable for their extremely developed proboscis-like inner mouth, which is used to secrete the resin to build up the hive walls.
Praetorians are bigger and stronger than the Warriors and are seen to have a developing crown. Their primary role within the hive is to guard key locations of importance or interest, and, if nothing else, to protect the Queen herself. Most Praetorians can be found very close to the Queen's chambers. The physical features of the Praetorian are pristine and very similar to the Queen's: it has a crown-like head crest, large size, and great strength.
 
   
In ''Alien vs. Predator: Extinction'', the Praetorian is said to be created by special eggs and Facehuggers known as a royal Facehugger (these are generally larger and a darker color than normal Face huggers). However, others speculate that Praetorians evolve from the Warrior caste. The Queen selects a Warrior to become a Praetorian, and the Warrior is then attacked by fellow Xenomorphs from the same hive and banished. The Warrior must survive on its own for a long period of time. It grows and sheds, becoming approximately fifteen feet tall and gaining its head crest. It returns to the hive as a worthy guard to the Queen.
+
The '''Carrier''' caste and the '''Ravager''' caste are both large, specialized forms derived from Praetorians. The Carrier's function is to harbor, protect and transport facehuggers, which will cling to the protrusions on its dorsal spines, and may launch themselves at nearby creatures. The Ravager, on the other hand, is a purely offensive caste which seeks only to destroy opponents, regardless of whether they could make useful hosts or not. They're only really employed when the hive is at war.
   
In the ''Directors Cut of Alien 3'' it is shown that immature Queens (Praetorians) are created through a special Facehugger known as the Royal Facehugger which carries a genetic code known as the Royal Jelly Line, which is passed from the Queen itself to the Facehugger and embryo.
+
A particularly dangerous, but seldom-seen possible caste is the '''Crusher'''. This massive, tank-like, heavily-armored quadruped is mostly known for its wide bulletproof cranial shield. Despite being as large as a Praetorian, it's capable of achieving great speed, lending support to the idea that it might represent a Praetorian matured from the "Runner" (Xenomorphs spawned from quadrupedal hosts, such as dogs). Another possibility is that the Crusher might represent a mutation, rather than a naturally-occurring caste.
   
In the 2010 ''Aliens v.s. Predator'', the main Xenomorph, "Number 6", Molts/transforms into a Praetorian then into a Queen after the first queen and hive were killed by an explosion.
+
Other less prominent castes include the '''Lurker''': essentially a Drone which, as its name indicates, specializes in stealth tactics. The poorly-known '''Boiler''' and '''Spitter''' castes were encountered by the crew of the USS ''Sephora'' on LV-426; as was the afore-mentioned Crusher. Although most Drones can spit acid, the Spitter possesses specialized pouches on its head to store additional quantities. The Boiler, meanwhile, is probably one of the strangest castes: a deformed-looking alien whose suicidal attack consists of rupturing its own body and "exploding" in a rain of acid.
   
Some varying reports of Praetorians with massive shield-like growths on their forearms have been seen.
+
Although a few artificially-created individuals, such as the [[Rogue Xenomorph]], have been referred as "king", the existence of naturally-occurring Xenomorph '''Kings''' is dubious, supported only by apocryphal sources.
   
===Queen===
+
==History==
[[Image:Anguish.jpg|thumb|300px|A Queen Alien, attached to her ovipositor.]]
+
[[File:XenomorphImageryLV223.jpg|thumb|250px|The image of a Xenomorph visible on the walls of the Engineer's temple on LV-223, in 2093.]]
The [[Xenomorph Queen|Queen]] is the largest and most intelligent Xenomorph and can grow incredibly large, up to 100 feet tall if given time. She lays many eggs that hatch to become the first stage of Xenomorph. It is unclear whether the Queen engages in combat outside of protecting her hive. The Queen is usually nestled deep within the hive, protected by Praetorian guards.
+
It is heavily implied that Weyland-Yutani's original synthetic android David was the chief designer of the first Xenomorph egg and therefore the creator of the species. However, there are no solid facts as to the origins of the Xenomorph species; instead, there are many theories which cannot be confirmed. They may be an artificially created species, or they may have evolved naturally on a planet very different from Earth.
   
She has been known to display some logic-based intelligence, primarily in using simple human technology such as lifts. She is the most dangerous of the hive, displaying extreme aggression and using her intelligence to devastating effect.
+
It has been implied that the Xenomorph species derives from the [[Black Liquid]]: a living biological weapon created by the [[Mala'kak|Engineers]], and stored in special canisters inside a temple on LV-223, a moon of the gas giant Calpamos, in the Zeta Reticuli System. The Liquid was created to infect other life forms and either kill them or merge with their genetic structure, giving rise to new and extraordinarily hostile mutations. Simple worms mutated by this substance, for instance, developed into the [[Hammerpede]]s: a species which shares some traits with Xenomorphs, such as the acidic blood.
   
When attached to her egg sac (ovipositor), she is immobile and vulnerable to attack. When she removes herself from it, however, she can move surprisingly fast. She attacks with her four clawed arms, as well as her long, bladed tail. She has also been shown to use her main and inner jaws in combat.
+
In 2093, the USCSS ''Prometheus'' arrived on LV-223 and the temple and the Black Liquid were discovered. The android David (built to be curious and Human-like) secretly infected Charlie Holloway with a drop of the mutagen, and Charlie then impregnated Elizabeth Shaw; resulting in a large facehugger-like lifeform known as the [[Trilobite (Prometheus)|Trilobite]]. Elizabeth, in pain from the creature growing within her, then removed the lifeform by entering the automated surgery table on-board Meredith Vicker's exclusive ship. The lifeform later encountered an Engineer and ensnared him much like a facehugger; thus, creating the [[Deacon]] which highly resembles the Xenomorphs, albeit with some differences, such as the pointed head and absence of a tail.
   
Interestingly enough, it seems that the size of Queens varies. In ''Aliens'', the Queen was shown to be maybe only twice the size of a Drone (this also may be due to her being so relatively young). In ''AVP'', she is shown to be considerably larger - three or four times the size of a Drone. This could be explained in a similar fashion to an older Drone's ridged head. The Queen in ''AVP'' was very old; although kept in a dormant state for long periods of time, she could have been alive for several millennia, or she could have been an Empress. Queens usually stand around 15 to 20 feet tall.
+
By the next year, David had hijacked an Engineer ship and traveled to an unnamed planet believed to be their homeworld, where he decimated the Engineers' settlement by unleashing the Black Liquid upon them and observed as the Liquid took over life forms native to the planet. Over the next ten years, David experimented with combining these native life forms with material taken from the bodies of Humans and Engineers alike. Meanwhile, on the planet's wild ecosystem, the first Xenomorph variety was already starting to develop, known as the [[Neomorph]].
   
Queens are created through Royal Facehuggers as seen in the ''Directors Cut of Alien 3 ''which produce Praetorians or immature Queens. When a Queen dies or abandons a hive a Praetorian may fully develop into a new Queen and take its mothers place. Whereas, normal embryos adopt characteristics from their host, the Royal Facehugger's does not. The Royal Facehugger carries within it the Royal Jelly Line, which is a genetic code passed down from the Queen Xenomorph to its chosen offspring. The embryo is more or less a genetic copy of its mother and as such will not adopt the characteristics of the host, but will retain the physical characteristics of the Xenomorph Queen. Regardless of host, the Praetorian will appear nearly exactly the same as its mother when it fully develops into a new Queen. Because of this, many fans speculate that the Queen is the only "pure blooded" Xenomorph as it will never appear differently.
+
At last, David's research led him to create a batch of genuine Xenomorph eggs, containing actual facehuggers. David knew he needed Human hosts to eventually gestate the Xenomorphs to fabricate his fantasy of becoming a god and creating something even better than his own makers, and this flight of fancy came true when the crew of the USCSS ''Covenant'' landed on the planet and one of the facehuggers impregnated Chris Oram, with the resulting chestburster developing as a modern-looking Xenomorph; possibly the first of its kind. The Xenomorphs have come to be known as "the Perfect Organism", fulfilling David's aspirations.
   
===Empress===
+
Thus, the chain of "uplifting" can be summarized as the following.
[[Image:65920.jpeg|thumb|left|300px|Dr. Eisenberg stands in the guard of the alleged Empress]]
 
In the video game ''Aliens vs. Predator 2'', there is mention of a Xenomorph Empress. Although very similar to a regular Queen, the Empress's main duty is to establish order on a planet with multiple hives. The only known differences between the two are their size (the Empress is substantially taller than a Queen, standing anywhere from 20 to 25&nbsp;ft. tall), and the crown (an Empress' crown has five points instead of the traditional three). It is possible that an Empress is simply the oldest queen on a planet, and the physical differences are the result of aging.
 
   
Dr. Eisenberg might have merely used the term "Empress" to refer to the Queen. However, the Empress is bigger than the average Queen seen in the Predator and Marine missions.
+
--> '''Engineer''' --> '''Human''' --> '''AI Synthetic''' --> '''Xenomorph'''.
   
It is also mentioned that after a hive grows to around 2,000 members, the younger Queens set out to establish new hives, and that if the Empress was to die, it would cause the younger Queens to fight over the new hive ruler. It's most likely that an "Empress" Xenomorph is merely a Queen that has dominated the other Queens in a hive. This would make the title "Empress" just that: a title. But in ''Aliens vs. Predator'' 2010, a very old Queen has a white skin color leading to the possibility that this Queen could have been an Empress.
+
However, this is heavily contradicted by the fact that the Xenomorphs are known to be a pre-existing species that was traditionally bred, reared and hunted by the Yautja intentionally for sport: a tradition that goes back thousands of years and has been practiced on Earth as well as other planets. Unless the Yautja or another species has found a way to time-travel and brought Xenomorphs to the distant past, this remains incompatible with the idea of Xenomorphs having been genetically-engineered by David.
   
==Predalien==
+
Another fact that casts doubt about the idea of David's creation being the first Xenomorph is that images representing what appear to be modern Xenomorphs were already present inside the walls of the Engineers' temples when David and the other ''Prometheus'' crewmembers arrived in 2093. The presence of these images could suggest that the Black Liquid was originally derived from the Xenomorphs, rather than vice-versa. In that case, specimens like the Deacon, the Neomorphs and David's Xenomorph could represent various stages of regression to a more ancestral form.
[[File:PredAlien_(1).jpg|thumb|320px|A Xenomorph formed from a [[Yautja]] host.]]
 
Like normal Xenomorphs, a [[Predalien]] gains traits from its host. But from the Chestburster stage, it is noticeably different from other Xenomorphs. It is a somewhat dark shade of green with external mandibles, due to its Predator (Yautja) heritage.
 
   
They lack speed, and their acid blood is not as deadly as a normal Xenomorph's. If a Predalien is part of a hive that has no Queen, it may serve as Queen due to its reproductive capabilities - its mandibles hold the host's head in place while its inner mouth implants one or more Xenomorph embryos into the host's throat, similar to the function of a Facehugger. Up to four Xenomorph embryos may be planted in a host, if the Predalien needs to build up numbers quickly. It also possesses higher intelligence than normal Xenomorphs. Though an accepted breed among the Xenomorphs, the Yautja believe this kind to be abominations and must be vanquished by any means necessary.
+
[[File:K-series-battle.jpg|thumb|left|250px|Regular Xenomorphs (black) engaged in war against the Human-created "K-series" Xenomorphs (yellow).]]
  +
In any case, it is certain that there is some kind of link between the Xenomorphs and the Mala'kaks, a.k.a. Engineers or "Space Jockeys". The Xenomorph could be the result of genetic manipulation by the Mala'kaks, created as a terraforming mechanism about ten million years ago, which went terribly wrong. A Mala'kak ship found as a derelict on LV-426 in 2122 was shown to have an entire chamber filled with Xenomorph eggs, apparently held in stasis for a long time. It's possible that the Mala'kaks used the Xenomorphs as weapons and/or research subjects, but the details are still unknown.
   
===Design===
+
Another idea is that the Xenomorph were the alpha predators of their own ecosystem on a nightmarish and harsh planet (assumed to be Xenomorph Prime, but there is no solid evidence). Without their native ecosystem to keep them in check, they developed into a separate dominant species. The Mala'kak, the Yautja, Humans and the [[Reaper (Aliens: Reapers)|Reapers]] began showing interest and started using them as means of sport, terraforming mechanisms, biological weapons, culinary delicacies (in the case of the Reapers and [[Alien (Aliens: Taste)|a giant unnamed reptilian race]]) and scientific experiment subjects, with various results. Experiments such as the K-Series, the [[Rogue Xenomorph]], the [[Xenoborg]]s and the [[White Hybrid]]s; as well as natural mutations such as the Red Xenomorphs have proved again and again how dangerous the species' biological plasticity can be; and yet, the victories of the traditional black-skinned Xenomorphs against many of these challengers (such as the Reds, the K-Series and the Rogue) have shown that the "Perfect Organism" moniker is still appropriate.
Though maintaining the basic design shown in the ''Aliens vs. Predator'' video games, numerous artistic liberties were taken in its film portrayal. Or rather, would have been taken. One abandoned concept was to have the Predalien reproduce by injecting victims with "DNA acid" through its tail, causing the victim to swell and explode.
 
   
Another is the Predalien's inherited tendency to skin victims. This was probably dropped because skinning victims aren't something that comes instinctively to Predators, but rather a learned behavior.
+
==Appearances==
  +
[[File:Xenomorph-design.jpg|thumb|250px]]
  +
====Films====
  +
*''Alien'' (1979)
  +
*''Aliens'' (1986)
  +
*''Alien³'' (1992)
  +
*''Alien Resurrection'' (1997)
  +
*''Alien vs. Predator'' (2004)
  +
*''Aliens vs. Predator: Requiem'' (2007)
  +
*''Alien: Covenant'' (2017)
   
There are also many different kinds of xenomorphs not listed here. For more information, check the "See Also" Section below.
+
====Literature====
  +
*''Aliens: Earth Hive'' (1992)
  +
*''Aliens: Nightmare Asylum'' (1993)
  +
*''Aliens: The Female War'' (1993)
  +
*''Aliens: Genocide'' (1993)
  +
*''Aliens vs. Predator: Prey'' (1994)
  +
*''Aliens: Alien Harvest'' (1995)
  +
*''Aliens: Rogue'' (1995)
  +
*''Aliens: Labyrinth'' (1996)
  +
*''Aliens: Music of the Spears'' (1996)
  +
*''Aliens vs. Predator: Hunter's Planet'' (1997)
  +
*''Aliens: Berserker'' (1998)
  +
*''Aliens vs. Predator: War'' (1999)
  +
*''Aliens: Original Sin'' (2005)
  +
*''Aliens: DNA War'' (2006)
  +
*''Aliens: Cauldron'' (2006)
  +
*''Aliens: Steel Egg'' (2007)
  +
*''Aliens: Criminal Enterprise'' (2008)
  +
*''Aliens: No Exit'' (2008)
  +
*''Alien: Out of the Shadows'' (2014)
  +
*''Alien: Sea of Sorrows'' (2014)
  +
*''Alien: River of Pain'' (2014)
  +
*''Alien: Invasion'' (2016)
  +
*''Alien vs. Predator: Armageddon'' (2016)
  +
*''Aliens: Bug Hunt'' (2017)
  +
*''Alien: The Cold Forge'' (2018)
  +
*''Alien: Echo'' (2019)
  +
*''Alien: Isolation'' (2019)
  +
*''Alien: Prototype'' (2019)
  +
*''Aliens: Phalanx'' (2020)
  +
  +
====Video games====
  +
*''Aliens versus Predator'' (1999)
  +
*''Aliens versus Predator 2'' (2001)
  +
*''Aliens versus Predator: Extinction'' (2003)
  +
*''Aliens: Extermination'' (2006)
  +
*''Aliens vs. Predator: Requiem'' (2007)
  +
*''Aliens vs. Predator'' (2010)
  +
*''Aliens: Colonial Marines'' (2013)
  +
*''Alien: Isolation'' (2014)
  +
  +
====Tabletop games====
  +
*''Aliens Adventure Game'' (1991)
  +
  +
====Comics====
  +
*Dark Horse Comics
  +
  +
==Gallery==
  +
===Life stages===
  +
<gallery>
  +
Ovomorphs.jpg|Ovomorphs
  +
Facehuggers.jpg|Facehuggers
  +
Facehugger.jpg|Facehugger attached to host's face
  +
Chestburster.jpg|Chestburster
  +
XenomorphXX121.png|Adult
  +
</gallery>
  +
  +
===Hive castes===
  +
<gallery>
  +
AVP Drone.jpg|Drone
  +
AlbinoDroneXenomorph.jpg|Albino Drone, a.k.a. "Worker"
  +
Lurker-full.png|Lurker
  +
WarriorXenomorph.jpg|Warrior
  +
PraetorianXenomorph.jpg|Praetorian
  +
CarrierXenomorph.jpg|Carrier
  +
Ravager.png|Ravager
  +
BoilerXenomorph.png|Boiler
  +
CrusherXenomorph.jpg|Crusher
  +
SpitterXenomorph.jpg|Spitter
  +
XenomorphPalatine.jpg|Palatine
  +
XenomorphPalatines.png|Palatine
  +
XenomorphQueen.jpg|Queen
  +
RoyalFacehugger1.jpg|Royal Facehugger
  +
RoyalFacehugger2.jpg|Royal Facehugger
  +
RoyalChestburster.jpg|Royal Chestburster
  +
RoyalChestburster2.jpg|Royal Chestburster
  +
XenomorphEmpress.png|Empress
  +
XenomorphQueenMother.jpg|Queen Mother
  +
XenomorphKing.jpg|King
  +
</gallery>
  +
  +
===Host-based strains===
  +
<gallery>
  +
CrocodileXenomorph.png|Crocodile
  +
XenomorphRunner.png|[[Dog]] ("Runner")
  +
RunnerChestburster.jpg|Runner chestburster
  +
Xenomorph1979.jpg|[[Human]]
  +
JockXenomorph.jpg|[[Mala'kak]]
  +
TarkatanXenomorph.png|[[Tarkata]]n
  +
Predalien.jpg|[[Yautja]] ("Predalien")
  +
Predalien-1.jpg|Predalien chestburster
  +
BerserkerXenomorph.jpg|[[Super Predator]]
  +
ParademonXenomorphs.jpg|[[Parademon]]
  +
ParademonXenomorphQueen.jpg|Parademon Queen
  +
ReaperXenomorph.jpg|[[Reaper (Aliens: Reapers)|Reaper]]
  +
ReaperXenomorphQueen.jpg|Reaper Queen
  +
ShokanXenomorph.png|[[Shokan]]
  +
VampireXenomorphQueen.png|[[Vampire]] Queen
  +
XenomorphQueen-AliensEarthAngel.jpg|[[Alien (Aliens: Earth Angel)|Unknown]] Queen
  +
Chestburster-AliensEarthAngel.jpg|[[Alien (Aliens: Earth Angel)|Unknown]] chestburster
  +
Xenomorph-AliensIncubation.jpg|[[Alien (Aliens: Incubation)|Unknown]]
  +
Chestburster-AliensIncubation.jpg|[[Alien (Aliens: Incubation)|Unknown]] chestburster
  +
ArachnidXenomorph.png|"Arachnid Alien"
  +
FigBullLoose1a.jpg|"Bull Alien" (implied to be spawned from actual cattle)
  +
GorillaXenomorph.jpg|"[[Zeevanian Ape|Gorilla Alien]]"
  +
GorillaXenomorph-Kenner.jpg|"Gorilla Alien"
  +
GorillaXenomorph-NECA.jpg|"Gorilla Alien"
  +
GorillaXenomorphQueen.jpg|"Gorilla Alien" Queen
  +
Aliens-crab.jpg|"Killer Crab Alien"
  +
MantisXenomorph.jpg|"Mantis Alien"
  +
MantisXenomorph-Kenner.jpg|"Mantis Alien"
  +
MantisXenomorph-NECA.jpg|"Mantis Alien"
  +
NightCougarXenomorph.jpg|"Night Cougar Alien"
  +
Aliens-panther.jpg|"Panther Alien"
  +
FlyingParasiteXenomorph.jpg|"Flying attack parasite" (launched from the back of the "Night Cougar" and "Panther" strains)
  +
RhinoXenomorph.jpg|"Rhino Alien"
  +
AlienRhyno1.jpg|"Rhino Alien"
  +
ScorpionXenomorph-Kenner.jpg|"[[Unidentified scorpion-like creature|Scorpion Alien]]"
  +
ScorpionXenomorph.jpg|"Scorpion Alien"
  +
Snake Alien.jpg|"Snake Alien"
  +
FigSwarm1a.jpg|"Swarm Alien"
  +
Boar Alien.jpg|"Wild Boar Alien"
  +
</gallery>
  +
  +
===Mutations and artificial variants===
  +
<gallery>
  +
KSeriesXenomorph.jpg|Kadinsky-Series ("[[K-Series]]")
  +
PredalienQueen.jpg|Kadinsky's Predalien Queen
  +
Planet4Xenomorph.jpg|Praetomorph (a.k.a. Planet 4 Xenomorph)
  +
Planet4Chestburster.png|Praetomorph chestburster
  +
Neomorph.jpg|[[Neomorph]]
  +
Bloodburster.png|[[Neomorph|Bloodburster]]
  +
Leech-AliensExtermination.jpg|"[[Leech]]"
  +
FlyingXenomorph.jpg|Flying Xenomorph
  +
FlyingChestbursters.jpg|Flying chestbursters
  +
FlyingXenomorphQueen.jpg|Flying Queen
  +
AcidAlien.jpg|"Acid Alien"
  +
Infectoid2.jpg|Infectoids (hosts fused with a facehugger)
  +
Defender Xenomorph.jpg|Defender
  +
SmasherXenomorph.jpg|Smasher
  +
ArachnoidXenomorph.png|Arachnoid
  +
XenoChrysalis.JPG|Chrysalis
  +
Razor Claws.JPG|Razor Claws
  +
FlyingOctopedalQueen.jpg|Flying Octopedal Queen
  +
Cloned Drone.png|Cloned Xenomorph
  +
ClonedXenomorphQueen.jpg|Cloned Queen
  +
Newborn alien.jpg|[[Newborn Xenomorph]]
  +
RogueXenomorph.jpg|[[Rogue Xenomorph]]
  +
SewerMutationXenomorph.jpg|Sewer Mutation
  +
Xenoborg.jpg|[[Xenoborg]]
  +
</gallery>
  +
  +
===Others===
  +
<gallery>
  +
Bellybursters.jpg|Bellybursters
  +
GiantFacehuggers.jpg|Giant Facehuggers
  +
GiantFacehugger-Kenner.jpg|Giant Facehugger
  +
GiantFacehuggers-NECA.jpg|Giant Facehuggers
  +
SwimmingXenomorph1.jpg|Swimming Xenomorphs from Bracken's World
  +
SwimmingXenomorph2.jpg|Swimming Xenomorphs from Bracken's World
  +
Xenomorphs-LV223.jpg|Xenomorphs from LV-223
  +
Alien-RedAliens.jpg|[[Red Xenomorph]]s
  +
Redqueenmother.png|Red Queen Mother
  +
Bodyburster.jpg|[[Bodyburster]]
  +
PinkOvomorph.jpg|Pink ovomorph which generated the Bodyburster
  +
AquaAlien.jpg|"Aqua Alien"
  +
BlueXenomorph-Kenner.jpg|Blue-colored Xenomorph
  +
PinkXenomorph.jpg|Pink-colored Xenomorph
  +
KingXenomorph-Kenner.jpg|"King Alien"
  +
RavenXenomorph.png|[[The Raven (Xenomorph)|Raven]]
  +
TuskedXenomorphs.png|Tusked Xenomorph
  +
TuskedChestburster.png|Tusked chestburster
  +
JokerXenomorph.jpg|"Joker Alien"
  +
KillerCrocAlien.jpg|"Killer Croc Alien"
  +
FahrenheitXenomorph.png|"Fahrenheit Alien"
  +
Xenomorph-Animaniacs.jpg|''Animaniacs''
  +
Xenomorph-BrewsterRockit.jpg|''Brewster Rockit: Space Guy!''
  +
Facehugger-BrewsterRockit.jpg|''Brester Rockit: Space Guy!''
  +
Xenomorph-Conker.jpg|''Conker's Bad Fur Day''
  +
Xenomorph-Planet51.jpeg|[[Xenomorph Dog]] (''Planet 51'')
  +
Chestburster-Spaceballs.jpg|''Spaceballs''
  +
</gallery>
   
 
==Notes==
 
==Notes==
*The Xenomorph's design is originally featured in H. R. Giger's book ''Necronomicon'', named after the eponymous forbidden grimoire from the stories of H. P. Lovecraft.
+
[[File:Xenomorph-HRGiger.jpg|thumb|250px|H. R. Giger's design concept.]]
*The [[Tarkatan Xenomorph]] is a strain spawned with the [[Tarkata]] of ''Mortal Kombat''. It is featured in ''Mortal Kombat X''.
+
*The image that would eventually become the Xenomorph's design was originally featured in H. R. Giger's book ''Necronomicon'', named after the eponymous forbidden grimoire from the stories of H. P. Lovecraft.
*Within its franchise, the Xenomorph has been referred to as "Kane's son", a "creature", a "serpent", a "beast", a "dragon", a "monster", a "nasty", a "thing", a "bug", among others.
+
*The Xenomorph's method of reproduction is rather reminiscent of that employed by the [[Ixtl]], a species featured in the novel ''The Voyage of the Space Beagle'', which predates the Xenomorphs by almost 30 years. The first ''Alien'' film has even been accused of plagiarism regarding the book, although the producers denied any possible influence or connection.
[[File:Conkers Bad Fur Day - Final Boss Battle Heinrich|thumb|right|300px|Conker fights Heinrich]]
 
*Besides merging with the ''Predator'' franchise, the Xenomorph species has been featured in a myriad of other science-fiction and superhero sagas. It has been fought by several DC Comics characters, including Batman, [[Superman]] and the Green Lanterns.
 
*Xenomorphs make frequent appearances in the humorous comic strip ''[[:Brewster Rockit Universe|Brewster Rockit: Space Guy!]]''
 
*They appeared in the comedy show ''Robot Chicken''.
 
*The creature appeared in an episode of the cartoon comedy ''Animaniacs'' called "Space Probed".
 
*The [[Xenomorph Queen]] has also briefly appeared in an episode of the comedy series ''Family Guy''.
 
*In an episode of ''South Park'', Cartman is seen watching aliens and repairs they mostly come out at night throughout the episode.
 
*A small Xenomorph appears as a dog-equivalent on ''Planet 51'' and is shown to urinate acid.
 
*Xenomorphs have also made cameos in some ''Star Wars'' material, though they are not canon.
 
*In an episode of Chip n Dale Rescue Rangers, the Rescue Rangers watch a science fiction movie with an alien resembling a Xenomorph.
 
*The Xenomorph's method of reproduction is rather reminiscent of that employed by the [[Ixtl]], a species featured in the novel ''The Voyage of the Space Beagle''. The first ''Alien'' film has even been accused of plagiarism regarding the book, although the producers denied any possible influence or connection.
 
 
*Another possible inspiration for the Xenomorph is the small deep-sea crustacean ''Phronima'', which is physically similar to some Xenomorphs (particularly the Xenomorph Queen) and is also an endoparasitoid, laying its eggs inside the body of deep-sea salps and killing them from the inside, after which the crustacean continues to inhabit the salp's hollowed body.
 
*Another possible inspiration for the Xenomorph is the small deep-sea crustacean ''Phronima'', which is physically similar to some Xenomorphs (particularly the Xenomorph Queen) and is also an endoparasitoid, laying its eggs inside the body of deep-sea salps and killing them from the inside, after which the crustacean continues to inhabit the salp's hollowed body.
*The Xenomorph's design has inspired the creation of the ''Metroid'' villain known as [[Ridley]], which is a reference to Alien's director Ridley Scott. They also bear a resemblance to [[Space Pirates]], the antagonist species in the ''Metroid'' game series.
+
*Within its franchise, the Xenomorph has been referred to as "Kane's son", a "creature", a "serpent", a "beast", a "dragon", a "monster", a "nasty", a "thing", a "bug", among others.
*In the ''Dragon Ball Z'' series, the first main villain Frieza/Freeza has a third form transformation that resembles this species of alien life (the signature long cranium).
+
*Besides merging with the ''Predator'' franchise, the Xenomorph species has been featured in a myriad of other science-fiction, superhero and comedy franchises.
*In ''Lilo & Stitch: The Series'', [[Experiment 627]] is shown to have an extendable appendage in his mouth similar to the Xenomorphs.
+
**It appeared in an episode of the cartoon comedy ''Animaniacs'' called "Space Probed".
*A Xenomorph named Heinrich serves as the final boss of the Nintendo 64 game ''Conker's Bad Fur Day''.
+
**Xenomorphs make frequent appearances in the comic strip ''[[:Category:Brewster Rockit Universe|Brewster Rockit: Space Guy!]]'', with the most prominent Xenomorph character being Philbert, the "son" of human engineer Cliff Clewless, who figures among the few known survivors of a facehugger implantation.
*Judging from the fact that virtually any Xenomorph can turn into a Praetorian and then a Queen, they are probably all female and reproduce asexually; which is called parthenogenesis, several organisms apply this reproductive ability. Either that or they are able to change sexes during life as is the case with some species of fish and amphibians. Or being hermaphroditic: capable of having both sexes.
+
**A Xenomorph named Heinrich serves as the final boss of the Nintendo 64 game ''Conker's Bad Fur Day''.
*In ''Aliens'', the Xenomorphs seem to shake their head slightly before attacking their prey.
+
**Xenomorphs have been fought by several DC Comics heroes, including Batman, [[Kryptonian|Superman]] and the Green Lanterns.
*Some fans have noted similarities between Xenomorphs and the Propagators found on the Ragnarok in ''Final Fantasy VIII''. It is possible that the Xenomorphs served as the inspiration for this creature, which is territorial, carnivorous, and is found only in remote locations in space. 
+
**The Xenomorph Queen has also briefly appeared in an episode of the comedy series ''Family Guy''.
*In Space Quest V, a science fiction parody adventure game, a Facehugger is found in a garbage load and adopted by the player character and ships captain: Roger Wilco. It's urine, in reference to its blood, is highly acidic and must be neutralized to protect the ship, but later is used in a jailbreak. In Space Quest VI a Xenomorph is shown sneaking into the shuttle of a parody of Ellen Ripley: Ellen Wrigley. 
+
**The Tarkatan Xenomorph is a strain spawned from the [[Tarkata]] of ''Mortal Kombat''. It is featured in ''Mortal Kombat X''.
  +
**A small Xenomorph appears as a dog-equivalent on ''Planet 51'' and is shown to urinate acid.
  +
**They appeared in the comedy show ''Robot Chicken''.
  +
**A singing and dancing alien bursts out of John Hurt's chest in the 1987 sci-fi comedy ''Spaceballs''. Unlike most chestbursters, it possessed fully-developed legs and red eyes.
  +
**Xenomorphs have also made cameos in some ''Star Wars'' material, though they are not canon.
  +
**According to Derrick J. Wyatt, the Nemetrix from ''Ben 10: Omniverse'' can accept Xenomorph DNA.
  +
*Additionally, the design of the Xenomorph has become so iconic that it inspired numerous others.
  +
**The [[Xeno (Alone in the Dark)|Xenos]] from ''Alone in the Dark'' are named and designed after them.
  +
**In an episode of ''Chip 'n' Dale Rescue Rangers'', the Rescue Rangers watch a science fiction movie with an alien resembling a Xenomorph.
  +
**In the ''Dragon Ball Z'' series, the first main villain [[Frost Demon|Frieza]] has a third form transformation that resembles a Xenomorph, particularly sharing its signature long cranium.
  +
**Some fans have noted similarities between Xenomorphs and the Propagators found on the Ragnarok in ''Final Fantasy VIII''. It is possible that the Xenomorphs served as the inspiration for this creature, which is territorial, carnivorous, and is found only in remote locations in space.
  +
**In ''Lilo & Stitch: The Series'', [[Experiment 627]] is shown to have an extendable appendage in his mouth similar to the Xenomorphs.
  +
**The Xenomorph's design has inspired the creation of the ''Metroid'' villain known as [[Space Dragon|Ridley]], which is a reference to Alien's director Ridley Scott. They also bear a resemblance to [[Space Pirate]]s, the antagonist species in the ''Metroid'' game series.
  +
**The ''Space Quest'' series of science fiction parody adventure games, feature several references and homages to the Xenomorph. In ''Space Quest II'', a "spiny alien" resembling a Xenomorph with big red lips appears; if it catches the player, Roger Wilco, it kisses them and they later die of a chestburster. In ''Space Quest V'', a creature similar to a facehugger is found in a garbage load and adopted by Roger. Its urine, in reference to its blood, is highly acidic. In ''Space Quest VI'', a Xenomorph is shown in a "cameo" easter egg, sneaking into the shuttle of a parody of Ellen Ripley: Ellen Wrigley.
  +
**The [[w:c:non-aliencreatures:Pizza Monster|Pizza Monsters]] from the 1987 ''Teenage Mutant Ninja Turtles'' series are clearly designed after the Xenomorphs; as are the Squirrelanoids from the 2012 series.
  +
*In ''Aliens'', the Xenomorphs seem to shake their heads slightly before attacking their prey.
  +
*The fact that they have no visible eyes was conceived by Giger in his original design, because he felt that it made the creatures much more frightening if one could not tell they were looking at them.
  +
**In the original ''Alien'' film, the top of the creature's head was semi-transparent, with empty eye sockets of human appearance visible within. This element was dropped in later movies, but reused for the Predalien design, on the front portion of its skull.
  +
**In ''Alien³'', a fish-eye lens represented the Runner's sight, but it is unknown if this is really how it sees or simply a filmed representation of the creatures' sensory perception.
  +
**The idea that a Xenomorph may have eyes deep inside its skull is seemingly lent support by early models and toys of the Warrior Xenomorph, while ''Alien'' was still the only existing movie in the timeline. These showed an actual, physical, humanoid skull built under the smooth carapace, with the smooth top working like a one-way visor.
  +
**In the 2010 ''Alien vs. Predator'' game, it is mentioned in one of the Marine audio tapes that Xenomorphs have vision. The game implies that the Xenomorph sees using its attack tongue, though this may be for gameplay purposes rather than factual information.
  +
**In the novelization of the movie ''Alien'', the creature is held mesmerized by a spinning green light for several minutes.
  +
*The Xenomorph has been portrayed in noticeably different ways throughout the film series. Much of this was due to the continuing advancements made in the field of special effects, technology, and techniques used to bring it to life.
  +
**In the original ''Alien'' film, and in the sequel ''Aliens'', Xenomorphs are depicted as tall, slender creatures with a roughly Human biomechanical design. The chest area appears to be rib cage-like in design.
  +
**In later films, such as ''Alien: Resurrection'' and ''Alien vs. Predator'', they are depicted as being shorter and bulkier organisms, as well as being more quadrupedal, portrayed by either stuntmen in suits for close-ups, or computer-generated imagery for their full form.
  +
**In ''Aliens'', Xenomorphs are depicted as having ridges along their cranium, while in all other films they have smooth cowls covering their skulls. It was speculated in the ''Aliens'' bonus DVD that this was due to these Xenomorphs having had more time to mature, compared to the Xenomorphs in the other films. In the comics and various video games (''Aliens vs. Predator: Extinction'', ''Alien vs. Predator'' (SNES), ''Aliens vs. Predator 2''), this was depicted as one of the visual differences between the Xenomorph Drone and Warrior castes.
  +
**In ''Alien'' and ''Alien³'', the Xenomorph has six fingers, with the index and middle fingers conjoined into one digit, ring and little fingers also conjoined, and thumbs on both sides. In ''Aliens'', the Xenomorphs are shown with five fingers, with the second thumb missing. In ''Alien: Resurrection'' and ''Alien vs. Predator'', the aliens have four fingers, though the middle two appear to be a fusion of two digits. No explanation is given in the films for the fluctuating number of digits, although the creature's well-known genetic plasticity probably accounts for that.
  +
**Originally, the Xenomorph's tail was roughly the length of the rest of its body, with a small, almost surgical stinger-like barb on the end; but from ''Alien³'' onward, the tail has extended in length and features a large, knife-like blade at the tip. In ''Alien: Resurrection'' and ''Alien vs. Predator'', the tails have also supported a ridge of spikes right before the blade. This was introduced in ''Alien: Resurrection'' to help them swim convincingly, and was left intact in ''Alien vs. Predator''. The tail itself is shown to be of incredible length during ''Alien vs Predator'', measuring almost its full body length.
  +
**The original shooting script for ''Aliens'' featured a scene in which Lieutenant Gorman was "stung" by a Xenomorph's stinger. He was not killed, merely stunned, and the barb remained lodged in his shoulder. The novelization also included this scene, though the final cut of the movie does not. This attribute is used later on in various games.
  +
*In a cut scene in ''Alien'' (included in the Special Edition), Ripley found two of her cocooned colleagues actually being turned into Xenomorph eggs. This suggests that Xenomorphs can convert Humans into eggs when there is no Queen, although this may have been scrapped as many other features of the Xenomorphs were in later movies (such as the transparent skulls and empty eye sockets). In the book, it's described how the Drones are able to implant a fetus in up to four hosts, thereby creating enough Drones and Warriors to start a hive with.
  +
*"On the pH scale, [the alien blood] would probably rank at a devastating negative four or lower", a previous author claimed. This is theoretically possible, despite the fact that pH is the minus logarithm of the free H-ions' concentration. To put this into perspective, water has a neutral pH of 7 and our stomach acid has a pH of 1, which would lie at the very bottom of the 1 to 14 scale. Attempts to discredit such a claim are challenged indirectly by chemists who have found that mixing antimony pentafluoride with hydrofluoric acid can produce a solution with a pH of -31. This therefore would render it 100,000 billion, billion, billion times more potent than stomach acid. It should be noted, however, that this acid is basically formed by mixing two incredibly strong acids together in the first place, which interact to become even more acidic. Though former theories have in fact stated that two potent chemicals (with perhaps some biological catalyst) may mix to create the acidic blood seen. Perhaps the strongest 'solo' acid would be the boron-based carborane with a pH of -18. Yet due to the structure of carborane, the H+ ions, which create the phenomenon known as acidity, are shared so efficiently between molecules that it would have no corrosive effects at all. Hence despite challenges it would appear even that which is known on Earth certainly leaves scope for the incredible properties of the aliens' acidic blood. It may also go without saying that different environments in other worlds could evolve "acid blood" that could also carry whatever nutrients that the Xenomorph needs.
  +
*In the first movie, it appeared that the eggs could sense when another creature crossed into some form of mist covering their nursery area. It's a widely accepted hypothesis that this was a containment field to keep the eggs dormant (this same mist has been used as such in ''Aliens Vs. Predator 2'' video game), put in place by a Mala'kak, a.k.a. "Space Jockey". When this mist was broken, the facehuggers appeared to be alerted, and went on the search for the host.
  +
*In the video game ''Alien Vs. Predator 2'', one of the alien missions requires the player to find a source of food in order for the chestburster to advance to its Drone phase. At the end of the level, a short cut-scene indicates that the chestburster consumes a house cat in a carrier. The scene does not show what happens during the change in the life cycle.
  +
*Though maintaining the basic design shown in the ''Aliens vs. Predator'' video games, numerous artistic liberties were taken in the film portrayal of the Predalian. Or rather, would have been taken. One abandoned concept was to have the Predalien reproduce by injecting victims with "DNA acid" through its tail, causing the victim to swell and explode.
  +
**Another is the Predalien's inherited tendency to skin victims. This was probably dropped because skinning victims isn't something that comes instinctively to Predators, but rather a learned behavior.
   
 
==See also==
 
==See also==
{{Xenomorphs}}
+
*[[Alien (Inseminoid)]]
  +
*[[Brood]]
  +
*[[Deacon]]
  +
*[[Hammerpede]]
  +
*[[Ixtl]]
  +
*[[White Hybrid]]
  +
*[[Xeno (Alone in the Dark)]]
   
==Sources==
+
== References ==
*[[Wikipedia:Alien (movie)]]
+
<references />
*[[Wikipedia:Aliens (movie)]]
+
*[[Wikipedia:Alien 3]]
+
==External links==
*[[Wikipedia:Alien Resurrection]]
+
*[[w:c:non-aliencreatures:Xenomorph XX121|Xenomorph XX121]] at Non-alien Creatures
*[[Wikipedia:AVP]]
 
*[[Wikipedia:List of castes from the Alien expanded universe]]
 
 
*[http://avp.wikia.com/wiki/Xenomorph AvP Wiki: Xenomorph]
 
*[http://avp.wikia.com/wiki/Xenomorph AvP Wiki: Xenomorph]
 
*[https://www.avpcentral.com/xenomorph-types Xenomorph types]
 
*[https://www.avpcentral.com/xenomorph-types Xenomorph types]
+
*[http://drshawtestament.tumblr.com/post/131706510396/testamentofdrelizabethshaw Testament of Dr. Elizabeth Shaw]
== References and Footnotes ==
+
[[Category:AVP Universe]]
<references />[[Category:AVP Universe]]
 
 
[[Category:Semi-Sapient Species]]
 
[[Category:Semi-Sapient Species]]
  +
[[Category:Races of the Milky Way Galaxy]]
 
[[Category:Hive Species]]
 
[[Category:Hive Species]]
[[Category:Parasitoidic lifeforms]]
+
[[Category:Transgenic Species]]
[[Category:Planetary Threats]]
+
[[Category:Parasitoidic Species]]
[[Category:Galactic Threats]]
 
[[Category:Xenomorph Variants| ]]
 
[[Category:Wildlife]]
 
[[Category:Transgenic Organisms]]
 
 
[[Category:Species that Metamorphosize]]
 
[[Category:Species that Metamorphosize]]
[[Category:Aliens on Earth]]
+
[[Category:Predators]]
  +
[[Category:Galactic Threats]]
 
[[Category:Hostile Species]]
 
[[Category:Hostile Species]]
[[Category:Insectoid Species]]
+
[[Category:Aliens on Earth]]
[[Category:Carnivores]]
+
[[Category:Sapient Prey Species]]
[[Category:Aggressive Species]]
+
[[Category:Species with Inherited Memory]]
[[Category:Parasitic Species]]
 
[[Category:Parasitic lifeforms]]
 
[[Category:Fictional Aliens]]
 
[[Category:Movie Species]]
 
[[Category:Live Action Species]]
 
 
[[Category:1979 Debuts]]
 
[[Category:1979 Debuts]]
  +
[[Category:Live Action Species]]
  +
[[Category:Movie Species]]
  +
[[Category:Comic Species]]
  +
[[Category:Literary Species]]
  +
[[Category:Video Game Species]]
 
[[Category:Species Designed by H. R. Giger]]
 
[[Category:Species Designed by H. R. Giger]]
[[Category:Aliens Portrayed by Tom Woodruff Jr.]]
 
 
[[Category:Aliens Portrayed by Javier Botet]]
 
[[Category:Aliens Portrayed by Javier Botet]]
[[Category:Races of the Milky Way Galaxy]]
+
[[Category:Aliens Portrayed by Tom Woodruff Jr.]]
[[Category:Predators]]
+
[[Category:Created Species]]
[[Category:Sapient Prey Species]]
+
[[Category:Oviparous Species]]
[[Category:Species with Inherited Memory]]
+
[[Category:Planetary Threats]]
  +
  +
[[uk:Ксеноморф]]

Latest revision as of 22:19, August 28, 2020

"You still don't understand what you're dealing with, do you? Perfect organism. Its structural perfection is matched only by its hostility."
―Ash

The Xenomorph XX121[3], better known just as Xenomorph (which literally translates to "strange form" from Greek ξενος, xenos=strange and morphe=form) or the "Alien", is an extraterrestrial hive-based endoparasitoid species with a multi-staged life cycle, possibly originating from the planet Xenomorph Prime.

One of the deadliest of all known alien species, these creatures require a host organism in order to reproduce. The appearance of the Xenomorph can vary depending on the host in which the embryo is implanted. The Human phenotype is generally around 7–8 feet (~ 2.13 - 2.43 meters) and roughly 136.0 to 181.4 kilograms in weight, with a long, muscular tail and large, curved, oblong head. The Queen of this species is generally twice as large (although some Queens have been shown to grow even larger, some surpassing 30 meters in height if given time) and possesses superior speed, strength and intelligence compared to her common offspring.

BiologyEdit

The physical form of a Xenomorph can vary widely depending on its life stage, hive, caste, age, and host. Its ability to incorporate genetic material from its host, coupled with the existence of numerous mutations and deviations which have originated naturally or artificially; makes the Xenomorph one of the most phenotypically diverse organisms in the galaxy.

A typical Xenomorph begins its life cycle as an egg-like creature (known as an ovomorph or simply egg) which, when detecting the presence of a potential host, opens up to release the second stage: a small arachnid-like life form (named the facehugger) which launches itself onto the host's face and impregnates it with an endoparasitoid larva. This parasite then consumes parts of the host from within and violently emerges from the host's chest cavity as a worm-like creature (grotesquely christened as the chestburster), which will quickly scurry away to find a safe place where it can molt and complete its metamorphosis into an adult Xenomorph, which happens, surprisingly enough, over the course of mere hours.

Although numerous varieties exist, adult Xenomorphs all tend to share some common traits: a vertebrate-like body, a protective dark exoskeleton, a long flexible tail, an elongated domed head and a toothed mouth hiding a secondary, extendable, proboscis-like inner maw. Little is known about their biology, but it is known that they eat with their inner or secondary mouths, not their outer mouths. This mouth is somewhat similar to the pharyngeal jaw of a moray eel. They also bleed an unknown and extremely corrosive fluid. This substance is dull yellow in color and often referred to as "blood", although whether it's used to transport nutrients through the body and/or serves principally as a defensive mechanism is not clear.

While the extremely corrosive fluids and tremendous resilience displayed by the creature might suggest an exotic kind of biochemistry, the fact that the Xenomorph not only feeds on Humans, but actually develops inside them, strongly suggests that its biology is carbon-based. The ability to inherit traits from its hosts also suggests that it incorporates genetic material from them, implying that the Xenomorph either has DNA, or is able to read and convert DNA into whatever means it uses to store genetic information. There is evidence that the genetic exchange is mutual (i.e. the parasite alters the host's DNA as well), given that Ellen Ripley's clones were created in an attempt to gain access to the Xenomorph Queen's genetic material, which wouldn't be possible otherwise.

Xenomorphs operate in hives made of a resin they produce, mixed up with their salivar fluids. The most commonly-observed castes are Drones, Warriors, Praetorians and Queens. The Queen can be generated in more than one way: from specialized royal facehuggers, or maturing from Praetorians, which in turn can mature from Drones or Warriors; by a process referred as 'molting'. Judging from the condition that any Xenomorph variant can potentially 'molt' and grow into a Praetorian and then a Queen, the Xenomorph species is likely all female and reproduces asexually by a process called parthenogenesis: a reproductive method practiced by many species on Earth and other planets. Alternatively, it's also possible that the aliens are either hermaphrodites or practice sequential hermaphroditism, i.e. being able to change sexes during life, as is the case with some species of fish and amphibians.

IntelligenceEdit

Most Xenomorphs appear to possess an intelligence level equivalent to that of a typical primate. It's well within their capabilities to learn relatively quickly, gathering information and making advantageous use of their environment. Although they do not demonstrate Human and Yautja-level intelligence as a species (such as abstract reasoning, introspection and technological advancement), their Queen appears to possess considerable acumen in her social behavior and manipulation of Human technology, such as cutting the power of the LV-426 colony and operating an elevator. While it may take considerable time for them to learn how to operate machinery[4], other Xenomorphs have displayed fast reasoning and the capacity to find creative, counter-intuitive solutions to problems, as exemplified by a group which, after noticing that they were being contained, intentionally murdered the weakest so that the acid of the Xenomorph's blood would eat through the floors.[5]

As the adult Xenomorphs are known to inherit physical characteristics from their hosts (for example, when a Yautja was infected, the parasite later developed into a "Predamorph" or "Predalien") it is possible that the intelligence level of the creature may be influenced by its host as well. Furthermore, being an eusocial species, it is possible that the intellectual capacity varies for each different caste.

Xenomorphs have demonstrated little emotion, though they are not completely devoid of fear, such as when they are in the presence of fire[6], which they are vulnerable to. They have also been shown to communicate pain through shrieks or screams when attacked.

It has been suggested that Xenomorph nests may operate under a hive mind, or a collective consciousness directed by the Queen, who can call back and give orders to her subjects, both telepathically and vocally with shrieks. In some cases, the Queen Mother Xenomorph communicates telepathically with potential hosts, inducing terrifying dreams and religious visions, which may even lead to the formation of cults with the Xenomorph as a god-like figure, not dissimilar to the cults of Cthulhu and other such entities. The most famous example of this phenomenon might have been Walter Golic, who received supposedly telepathic messages from a captured Xenomorph; which ultimately led him to release it and let it kill him. He called this Xenomorph "the Dragon", and viewed it as a god.

There is evidence that the Xenomorph hive mind also includes a collective memory that passes along even at a genetic level. Through the tests conducted on Ellen Ripley, it is revealed that the memory passed from Ripley onto the new generation of Xenomorphs allows them to read and understand different languages. Events on the LV-426 colony and the USM Auriga show that the species excels at observational learning. Another case of observational learning can be seen following a Xenomorph escaping its cell. It had learned that the consequences of attacking the observatory glass was a jet of extreme cold (possibly liquid nitrogen), triggered by a large red button on the console. When a crewman entered the now-empty cell to study the hole through which the Xenomorphs escaped, one of them entered the control room and activated the button using its inner jaw.

In the rare event that a Xenomorph finds itself under attack or otherwise vulnerable, it might display incredible creativity and cleverness. They are capable of moving quickly and silently in ventilation systems, despite their size, and will use such conduits for ambush, escape, or simply as an easy way to travel between areas.

Xenomorphs are conscious of the effects of their acidic blood, and will use it to their advantage - to break out of Human-constructed confinement, or as a weapon. They show some military tactics (such as retreating when overwhelmed), and can find ways to get around certain problems (such as pushing the red button to freeze a soldier in liquid nitrogen in the afore-mentioned incident). They know that the darkness is their ally, and break lights to create cover.

AnatomyEdit

Alien 1986

Warrior Xenomorph

A Xenomorph is equipped to be the perfect killing machine. They possess an exoskeleton much like that of a lobster, impenetrable to everything but the most powerful Human firearms (12-gauge shotguns, Pulse Rifles, and stanchion launchers are quite effective). Ash claims the creature's skin is made from "protein polysaccharides", so this would imply a substance similar to chitin. He also says the creature replaces its surface cells with polarized silicon, which is a very inert, heat resistant, and flexible polymer. This allows these creatures great environmental resistance. However, they are vulnerable to sudden, massive changes in temperature. It's been demonstrated that they can be destroyed by immersion in molten lead followed by sudden cooling with fire sprinklers, causing their silicon shells to shatter.

Attached at the ends of both of their arms are a set of long fingers and shiny, black, extremely sharp claws capable of slashing through almost anything within their grasp[7]. Their tail is long and flexible. Some, though not all, individuals also have ridges on top, and a serrated toxic tip at the end of the tail to lacerate enemies.

They stand at around 7 feet tall (~ 2.13 m), averaging in anywhere between 140 and 180 kg; although size may vary wildly depending on the host chosen, as seen for instance with the "Jock-Xenomorph": a gigantic creature spawned from a Mala'kak host.

Xeno head

A Xenomorph's outer mouth is filled with sharp teeth, but their main killing device is the inner jaw that shoots out to penetrate directly into the victim's brain. The inner jaw (also known as an "attack tongue") is a muscular appendage on the inside of the Xenomorph's mouth. All Xenomorphs have this trait, excluding the genetically-engineered Newborn Xenomorph. It consists of a cord of muscle with a small but extremely deadly mouth-like appendage on the end. This attack tongue is able to punch through almost anything, from bone to Yautja armor.

The plasticity of the Xenomorph phenotype is one of the species' most notable features, and has resulted in physical traits that diverge from individual to individual and from hive to hive. As an example of how a host can influence the morphology and skills of the parasitoid, a Xenomorph spawned by a dog displays a distinctly canine body structure, digitigrate legs, quadrupedal movement, and greatly enhanced speed compared to those spawned by Human hosts, which are typically plantigrade and often bipedal.

Even among those spawned exclusively from Humans, different Xenomorph hives can produce highly divergent individuals. Some are taller and lankier, with an almost erect posture. Others are shorter and bulkier, and move more quadrupedally. While most have smooth craniums, others have ridges, which may be attributed to their age (i.e. those which have more time to develop may end up with ridges) and/or caste (ridges being associated with Warriors, and smooth features with Drones).

When it comes to their digits, there are at least three different patterns.

  • Some Xenomorphs have six fingers, with the index and middle fingers conjoined into one digit, ring and little fingers also conjoined, and thumbs on both sides.
  • Others are shown with five fingers, with the second thumb missing.
  • A third phenotype has only four fingers, though the middle two appear to be a fusion of two digits.

On at least one occasion, Human-spawned Xenomorphs were observed to have a digitigrade, as opposed to plantigrade posture. However, it should be noted that these were spawned by a Queen grown from cells derived from a clone of Ellen Ripley, making their genetic heritage muddled at best.

Some Xenomorphs have tails that are roughly the same length as the rest of their bodies, equipped with a small, almost surgical stinger-like barb on the end. This stinger can be, and has been, used to perforate victims, and may turn loose from the tail and remain lodged in the victim's body, not unlike a bee stinger. Conversely, other specimens have tails that are considerably longer, and armed with a large, knife-like blade at the tip and sometimes with ridges of spikes right before the blade, which may aid in swimming.

HeadEdit

Xenomorph-AlienVsPredator2010videogame

A close-up of a Xenomorph head, revealing what might be interpreted as an eye.

The most notable feature of the Xenomorph species is the elongated, banana-shaped head. A potential explanation for this curious shape may be that the head may store muscles required to power the Xenomorph's inner mouth.

In terms of eyesight, the Xenomorph appears to be entirely eyeless. However, there are features on its head which could represent eyes, which are usually hard-to-see due to the fact that they're small and the same black color as the skin.

Other proposed conjectures include that the eyes might be similar to a desert-burrowing lizard's eyes; meaning that they lay under a thin layer of skin, yet are deep enough that they are not visible from the outside. In that case, their eyes could be hidden behind their black carapace and they see through it, similar to a one sided mirror (except in this case no one can see in, but the Xenomorph can see out). Some species of Earth fish, such as the Barreleyes, see through a transparent layer of skin; it is possible Xenomorph vision is similar. Another idea is that their whole head might represent one big insect-like eye.

Eyeless or not, it is widely assumed that a Xenomorph identifies enemies by sensing pheromones. This has never been explicitly confirmed nor denied, but a Drone will not kill a host that's already infected, so they must have some way of detecting the presence of the unborn parasite within.[8]

Secondary jawsEdit

The secondary jaws (also known as the inner mouth, double jaw, or maw) are another disturbing feature of the species. It's assumed that they're powered by extremely strong muscles inside the creature's elongated head, that enable it to be quickly launched and retracted, similar to the tongue of a chameleon. The albino Xenomorph Drone has a very long inner mouth that can secrete resin that's used to build the walls of their hives.

The inner mouth is typically the Xenomorph's close-combat weapon, as opposed to its long-range tail. The Xenomorph lashes it out of its outer mouth, and it destroys anything it hits, being able to put a hole in a thickened Yautja skull and still have enough momentum to plunge another hole through the back as it escapes. Yautja take them as souvenirs of their kills.

The secondary jaw is powered by muscles, as seen when a Yautja rubs a part of the interior (resembling the gills of a crab), a feature that can be seen from the external midsection on each side of the head, ovular in shape. Muscles rub along here, letting the mouth be pushed out like a piston through the target the Xenomorph has acquired.

The Yautja-spawned Xenomorph (a.k.a. "Predalien") has the ability to use its inner mouth to implant chestburster embryos directly into a host's throat, like a facehugger. Since that particular Predalien was also on her way to developing into a Queen, it's possible that all future-Queens have this ability.

Dorsal spinesEdit

Along the back of most Xenomorphs' bodies are a series of appendages that appear to have no clearly-defined function. It's still in debate what they are used for, with theories ranging from sensory organs to communication organs, to breathing apparatus, to defensive mechanisms, to structures that dissipate heat, to storing substances their bodies need, or to provide structures to carry around the young, underdeveloped chestbursters, the eggs or the facehuggers or as a counter weight to keep them from falling over when running. None of these ideas has been confirmed or denied so far.

One theory is that the four back appendages are used as a type of radar that the alien utilizes to see through extreme environments or detect movements. It is also said that the dorsal spines are used to secrete and possibly store the resin used to build their hives.

It is interesting to note that Xenomorph Drones have been observed to bury themselves in the ground, yet their spines are still shown just breaking the surface[9], implying some use when connected to the environment. This may be either biological (breathing, heat exchange, etc.) or sensorial (detecting the vibrations of marines walking on the ground above).

Other hypotheses include:

  • Perhaps the spines separate the dominant Xenomorphs from the weaker ones, for example, the smaller the spines, the weaker the Xenomorph.
  • The creatures might come from a mainly amphibious planet, and perhaps the spines are a mechanism to swim underwater faster to catch prey. They do not seem all that hydrodynamic, but it's possible to suppose the spines might be used for stability, like the dorsal fins of a dolphin (not that their shape seems very much efficient at that either).
  • The spines might be spiracles that take in and filter the air around them, while waste is expelled through the mouth. It is widely accepted that they do not have lungs, so this is possible, and yet implausible because Runners (a.k.a. dog-spawned Xenomorphs), don't have them. But it may be that the Runners have lungs.
  • The spines might be used as a defense mechanism, to repel enemies that try to sneak up on them from behind or above.
  • They might also be traits that the alien acquires by chance when developing inside the facehugger, putting the legs of the facehugger on the back. The chestburster does not develop directly from the facehugger (instead, the facehugger plants the egg/larva that will become the chestburster inside a host), but it's not impossible that it acquires genetic traits from it.
  • They might be used to blend in with the hive web when under attack.
  • The spines may be for chestbursters to latch onto, allowing the adult to bring them to a safer location.
  • If the alien uses echolocation to see its prey, these may be what they feel the vibrations from.
  • They may be used to carry unhatched eggs to a new location when the Queen dies, allowing them to still climb walls while on the move.
  • The spines may be used to distribute pheromones - to distinguish one from another, and from other hives.
  • The spines may allow a facehugger to hook their spider-like legs until a victim is near. The facehugger will let go of its crude form of transportation, find the victim, and proceed with the process of laying eggs.
  • The spines may also act as a counter balance, much like a cat's tail, so that the Xenomorph does not fall forward when running. Though in truth, a cat does not require a tail to balance properly while running, it more so helps to balance upon thin surfaces like fences and the backs of chairs, and since the Xenomorph already has a long tail, this idea has little credence.
  • They may be used for breathing, as it's possible that the inner jaws serve only offensive purposes. This also makes sense if one considers that they may have come from a swamp-like planet, where they would lay in wait for prey to wander by. This would also explain the 'dome' over their eyes (assuming they have eyes), which may have functioned similarly to a camel's second eyelids: allowing the alien to see, while preventing stuff from getting in its eyes.

The "Runner", a Xenomorph born from a dog or other quadrupedal host, is notable in that it doesn't have dorsal spines. This could be an adaptation to make its body more aerodynamic and thus more efficient for running.

TailEdit

It is accepted that the tail is an offensive weapon and little more. Though the creature can and will run on all four appendages, it often stands on its two hind legs so it can reach for its prey with its arms. While standing, it has also been seen to impale its victim with its tail, even to the point where it can raise a creature heavier than itself to eye level, possibly in preparation for a face-bite using the secondary jaws. This would clearly be impossible if the tail was needed for balance, as the already-shifting weight would be too awkward, causing the monster to fall.

As a weapon, the tail is extremely efficient, as it is long enough to attack from great distance and can be used in a variety of ways; for example, a Xenomorph has been observed to use its tail to knock the legs out from under a Yautja before trying to stab it.

The tail can be used in stealth attacks, since it is flexible enough to attack from a variety of positions, and is hard to notice if it is behind the enemy, or if the area is rather dark. Even when the sharp point is cut off, the tail is still deadly, as the Xenomorph can use the damaged tail to spray its acid blood from the severed tip over a wide area. Xenomorphs are also capable of using their tails as blunt-force weapons, clubbing their enemies with the vicious tail spikes.

Physical abilitiesEdit

ClonedXenomorphs-swimming

Xenomorphs are capable swimmers.

The adult Xenomorph is a living weapon, noted for their ferocity and deadliness in any condition. Once fully matured, they have great physical strength and agility. They are masters of stealth; a favored method of acquiring prey is to wait in a dormant state until an appropriate victim strays near, and then drop down silently from behind or use their tail to impale whoever walks by. The prey is generally blind to the fact that a Xenomorph is present, due to its propensity to camouflage itself within its nest walls or the surrounding artificial environment, given their biomechanical-like appearance. The Xenomorphs will also use their pitch black carapace to their advantage, lurking in the shadows whilst waiting for prey to stray too close.

Xenomorphs are shown to be able to take extreme amounts of physical damage that would kill any earthly life form. An example of this is a Queen that survived a multi-ton exo-suit falling on her from over 30 feet. Xenomorphs are capable of surviving with limbs shot off, stabbings and even shots through the head (though total decapitation kills them).

Adult Xenomorphs are quick and agile, and can clamber along ceilings and walls: a skill they exhibit freely whether they are evading others, attacking, or hunting. They can survive in extreme temperatures, are well-adapted to swimming, can respire in harsh atmospheres, and can survive in vacuum for indeterminate lengths of time. Their movements tend to be silent, and they do not radiate heat as their exoskeletal temperature matches the ambient temperature. They also salivate profusely. This saliva is not acidic, though some Xenomorphs do have the ability to spit acid, which may come from their stomachs, a special gland somewhere in their throats, or acid pouches lining the head. This can be used to blind victims, much like a spitting cobra.

Due to the absence of clearly visible eyes, it is possible that the creature uses echolocation to see its environment, much like bats. It may be for this reason that Xenomorphs hiss almost constantly, though there is evidence that they can detect light and darkness as well. Xenomorphs may be able to find their prey through electro-reception. This is the method sharks use to detect even the most hidden prey. Creatures with the electro-reception sense can detect the electromagnetic field all animals produce, allowing them to locate their prey by its heart beats, even if the prey is immobile. This would explain how Xenomorphs always know where the Humans are. Furthermore, the Xenomorphs can also detect whether a potential host is already infected, likely by sensing pheromones.

Xenomorphs produce a thick, strong resin, which they use to build their hives and cocoon victims. Cocooning is a trait used by Xenomorphs to reproduce quickly. A Human, or any other creature, if dragged away, may have a cocoon of saliva and resin placed over them (their face left free), usually in an area where the Queen has produced a large quantity of eggs, so that the facehuggers are able to latch onto them easily and deposit a Xenomorph larva inside their chest. Much like termites, they mix their viscous saliva with solids. It shows amazing heat and moisture-retaining qualities.

VulnerabilitiesEdit

Xenomorphs, in all stages of their life cycles, have been said to have vulnerabilities to heat. The use of molotovs and flamethrowers constitutes an effective technique to drive them off. The only Xenomorph not vulnerable to fire is the Predalien, which can secrete a layer over its body that cannot be ignited, although they are still visibly pained by temperature extremes, such as liquid nitrogen.

A rapid succession of extremes in both high and low temperatures apparently causes a thermal shock effect on a Xenomorph's exoskeleton. Xenomorphs are capable of adapting themselves to cold environments with little discomfort. However, the alien Queen is particularly vulnerable to fire, for unknown reasons.

Depending on the circumstances, Xenomorphs are shown to be both invulnerable and vulnerable to small firearms, ranging from 9mm to 5.56mm. This is seen when Vasquez and Lt. Gorman find themselves trapped in the ventilation between advancing aliens coming from both directions. Gorman fires with his pistol on one of them with no effect at all, instead it looks like the ammunition bounces off (presumably from the head carapace). In another occasion, however, Vasquez holds an alien at gun point and fires her pistol at the head, which apparently goes through and the alien rattles away, obviously damaged. High-caliber firearms, with the explosive rounds of a M41A Pulse Rifle may cause the creatures to detonate. High-energy beam weapons, such as the plasma weapons used by Yautja, appear to be the best way to kill the Xenomorphs, though pulse rifles appear to be the best way to repel large hordes of them since they can fire non-stop and are not prone to being destroyed like the plasma weapons.

Xenomorphs are not invulnerable to melee weapons, although such equipment is likely to be destroyed upon contact with their acidic blood.

Acidic bloodEdit

The body fluid of all Xenomorphs appears to be a highly concentrated acid. It is frequently referred to as "acid blood", although it isn't clear whether or not it's used to carry any nutrients through the body.

It is somewhat unlikely that this fluid carries oxygen for a few reasons: the first being that the Xenomorph has been known to survive in vacuums such as space (for short periods of time, at least). The second being that Bishop mentions that the fluid loses its acidity shortly after the creature's death due to oxidation[10]. On the other hand, this is plausibly unimportant as oxidation is a term in chemistry used for the loss of electrons rather than a reaction with oxygen. All acids are oxidized no matter what they react with, therefore this has no bearing on blood carrying oxygen.

The "acidic blood" is able to dissolve through almost everything except the Xenomorph's body. The creature itself apparently knows how corrosive its "blood" is, as one flicked it at a charging Yautja, and it has been used to escape cages (by killing a "brother"). Some specially-treated Yautja weapons can resist this acid, although how long exactly is unknown.

It has been often theorized that the Xenomorph "blood" may serve no function other than defense, being a liquid stored under the creature's skin that causes great harm to whoever succeeds in harming the Xenomorph. It remains possible, though, that the acid serves some function in the alien's metabolism, perhaps even as an actual blood system analogue. One possibility is that it may be an extreme analogue of stomach acid, and likewise serves to digest food. In that case, the Xenomorph's digestive system would be spread like a circulatory system throughout its body: the acid is so powerful that anything it consumes is immediately dissolved and the remains distributed over its body, with the extremely resistant walls of the "acid vessels" somehow allowing nutrients to be absorbed.

Genetic adaptationEdit

Alien 1992

A "Runner", a Xenomorph formed in a quadrupedal host.

Due to horizontal gene transfer during the gestation period, the Xenomorph also takes on some of the basic physical attributes of the host from which it was born, allowing the individual alien to adapt to the host's environment more efficiently.

Through experiments, it was discovered that the embryo attaches itself to a major artery of its host, to get nutrients as it grows. It is presumed that the DNA from the blood it acquires infuses itself with the embryo's DNA to make up for its lack of genetic structure.

It may take on a thicker, bipedal form with a darker exoskeleton if it comes from something that stands on two legs, such as a Human. When the host is a four-legged animal, it may take on a more slender, sleeker appearance, where it too moves as a quadruped, and has a more reddish/orange-colored exoskeleton. It may also take on some facial features of its host (such as mandibles when implanted in a Yautja). Predaliens (Xenomorphs spawned from Yautja hosts) have a yellow-green partial skin covering their exoskeletons.

Furthermore, it is conceivable that it derives some level of intellect from its host. The quadrupedal variant seems easier to trick than bipedal ones, and the Predalien appears to have a better understanding of weapons being used against it.

Life cycleEdit

EggEdit

XenomorphEggs

Xenomorph eggs.

The Xenomorph is born in egg form, laid in place by the hive's Queen, through the use of a detachable ovipositor. The egg is thick and gelatinous, usually with several membranes attached to the outer layers. It can take nutrients from the ground to support the creature inside. The egg has vein-like structures running through it, showing that it is actually a living creature, sometimes known as an ovomorph.

The Xenomorph hatchling - called a facehugger - is protected by a thick fleshy layer at the top of the egg, where the "shell" peels open when the facehugger senses creatures nearby. The sense that detects suitable organisms has to be very specific in what it chooses to respond to. Perhaps this is why it takes so long to open: various sensory organs study the approaching organism. It seems to be capable of distinguishing synthetic life from organic life.

Sometimes Xenomorph Queens can lay eggs that contain up to four facehuggers.

FacehuggerEdit

Alien facehugger

A facehugger attached to Kane aboard the Nostromo.

After the egg opens, the facehugger emerges and seeks out a nearby life form, latching onto its face, wrapping its tail around its airway, and implanting the Xenomorph embryo(s) by sticking a tube down the host's throat. This is seen sometimes when a facehugger is contained in water or lunging at a soon to be host.

It will coil its tail tighter around the airway to prevent premature removal, and an attempt to sever the fingers found that facehuggers possess the same acidic blood as an adult Xenomorph. The facehugger supplies oxygen to keep the host alive during the impregnating process. Once the embryo(s) has been implanted, the facehugger falls off, curls up, and dies.

Hosts usually fall into a short coma and wake up ravenously hungry. This can be explained as the embryo needing an immediate source of nutrients for its progression into the next stage of its life. Hours might pass between the host waking and their time of death. Yautja live the longest as a result of an extended incubation period. The reason for this is likely due to the genetic complexity of the host. The incubating chestburster requires more time for mitosis and cytokinesis due to the morphology of the Predalien.

However, in some cases, the hosts will awake not gradually but suddenly - just in time to be conscious of the chestburster's push out into the world. Their state of normalcy will last only seconds or minutes.

It's also proven that when a host awakens, there is some sort of a memory lapse in which they don't remember anything that has happened to them. This short-term memory loss is most likely a result of the temporary oxygen deprivation caused by the facehugger's tail, as it asphyxiates the host.

Different types of facehuggers are known to exist, including some highly abnormal variants. The royal facehugger will give rise to Queens or to members of the Praetorian caste, the latter which may be promoted to Queens later on. However, there's also a poorly-known caste of giant facehuggers which are also known as queen facehuggers, but don't seem to be related to Queens directly. Unlike regular facehuggers, these giants don't seek to impregnate hosts, but merely protect the ovomorphs. They may use their legs and tail to immobilize potential hosts, allowing regular facehuggers to latch onto the victims' faces and impregnate them[11].

Another highly aberrant form is the Infectoid facehugger, which doesn't implant an embryo, but rather fuses itself to the host's body, transforming the host into an undead zombie-like being, linked to the aliens' hive mind[12].

ChestbursterEdit

Alien chestburster

A chestburster

After attaching itself to a vein and gestating in the chest cavity, Xenomorph infants - called chestbursters - push and chew through the host's chest, causing severe pain, blood loss, shock and death. The host's rib cage is cracked open, bones bent outward. No one has survived this process other than Emil Zorn, who was fitted with an artificial torso following this encounter. However, Ripley was cryogenically frozen after she was cloned, and then had it surgically removed. It was also revealed that high amounts of stress can actually make the chestburster more frantic. This causes it to push and chew through the chest at a faster pace, therefore emerging slightly earlier than normal. On one occasion, the chestburster erupted out of the head of a host Human instead of the chest.

It is suggested that the removal of the chestburster would still lead to the death of the host due to the remaining alien tissue acting like a malignant tumor, in effect developing into a fatal cancerous growth.[13]

At this stage, the Xenomorph is small, limbless, and very vulnerable. Among other possibilities, its neck can be snapped. It needs to get to a safe area so it can reach its next life stage. It moves with its long tail, and can coil up and jump. It cannot climb on walls or ceilings, but despite these drawbacks it can traverse an area with astonishing speed.

In some cases, they turn into a cocoon[14], though this could be a subspecies. The common assumption is that the alien molts, grows legs, and develops much like a tadpole turning into a frog. Another common theory (the most accepted one) is that chestbursters shed their skin upon growing, as shown when Brett picks up a chestburster skin he found on the floor in an area the chestburster took shelter in.

At very rare times the chestburster emerges after the host has already died, which has been observed in an ox[15]. Why the ox died after it was implanted is unknown; though the most likely reason would be due to a combination of the stress of implantation coupled with the poor health of the animal. It is seen to be riddled with parasites and presumably spent much of its life in the harsh environment of Fiorina "Fury" 161. Strangely, in this circumstance, the chestburster lived. This was also seen after the Empress killed a Predator and the chestburster survived.

In some cases, morphological traits acquired from the host may already be visible in the chestburster stage, for example: a chestburster born from a Yautja will already display the characteristic mandibles of the race. Some types of chestbursters already have legs when they emerge, including the royal chestburster and the "Runner".

A variation of this stage is known as the bellyburster, which erupts from the host's abdomen, rather than chest. These seem to be formed when the host is a pregnant female, and the alien embryo develops inside her womb, presumably feeding on the fetus. A Predalien has been observed to impregnate several hosts with multiple embryos each, which later gave rise to bellybursters. Since multiple bellybursters can develop inside a single host's womb, they can be used as an efficient way for a young future-Queen to establish a new hive faster.

AdultEdit

Little is known about the transformation that occurs between the chestburster and adult phases. As already stated, the Xenomorph appears to molt before reaching maturity. Maturity is reached in a few hours, and involves a dozen-fold increase in mass, which would presumably require some form of nourishment. In the Nostromo, Ripley comes across a food locker that had been raided, apparently by the Xenomorph to get food.[16]

When the first Drone encountered on record was born in the Nostromo, it had a smooth, long head, and an upright-standing body. It had no visible eyes, a tail, and strange spines protruding from its back. However, many years later on LV-426, the same species was found, but they looked slightly different. The head was no longer smooth, but ridged. One theory is that the smooth-headed Xenomorph was a Drone, and the ridge-headed Xenomorphs were Warriors. This is supported by the fact that the alien aboard the Nostromo built a nest, which only Drones can do since it is part of their job in the colony.

Another widely accepted idea, however, is age - the Xenomorphs found on LV-426 were more than a few days old, while all of the others encountered were less than a day old. On the other hand, some hives seem to have a distinct coloration for each caste, in which the Drones are black and the Warriors are a very dark blue; the color difference indicating that age is not a factor.

Another variation was encountered on an expedition to Antarctica. These Warriors were less humanoid and sometimes walked on all fours. Their tails were longer, with a large, curved barb at the end. The head was smooth but much shorter than normal. It is important to note, however, that this particular Xenomorph hive was grown by the Predators, who introduced a hormone with unknown effects into the Queen's system.

As the Xenomorph has been shown to be an extremely adaptable organism, which lays hundreds of eggs, develops quickly and is highly efficient at altering its own genome to better fit the environment (absorbing traits from its hosts), it's very likely that some phenotype variations are simply the result of genetic variation between different populations, which evolve very fast.

Host-based variationsEdit

PredalienEdit

PredAlien (1)

A Xenomorph formed from a Yautja host.

Like normal Xenomorphs, a Predalien gains traits from its host. From the chestburster stage, it is noticeably different from other Xenomorphs. It is a somewhat dark shade of green with external mandibles, due to its Predator (Yautja) heritage.

They lack speed, and their acid blood is not as deadly as a normal Xenomorph's. If a Predalien is part of a hive that has no Queen, it may serve as Queen due to its reproductive capabilities - its mandibles hold the host's head in place while its inner mouth implants one or more Xenomorph embryos into the host's throat, similar to the function of a facehugger. Up to four Xenomorph embryos may be planted in a host, if the Predalien needs to build up numbers quickly. It also possesses higher intelligence than normal Xenomorphs. Though an accepted breed among the Xenomorphs, the Yautja believe this kind to be abominations that must be vanquished by any means necessary.

RunnerEdit

Runner2

A Xenomorph formed from a quadrupedal host.

Runners, a.k.a. "Dog Aliens", are produced from a facehugger jumping onto a dog or other quadrupedal species, such as an ox. They act as scouts for the hive, likely due to their quadrupedal and fast nature.

Runners are tinged a noticeable brown and run on four legs like the host they hailed from. However, they will walk and stand on two legs sometimes. On their back, there are no dorsal tubes, likely for better head mobility. Unlike most Aliens, they are digitigrade (i.e. they walk on their toes). Their chestbursters are not as larval as the other aliens, but rather a smaller, pale version of themselves.

The Runner is all about speed and agility, perhaps one of the fastest castes of Xenomorph ever encountered. It stalks its prey much like a lion or tiger, waiting for an unfortunate victim to come about and killing them outright, rather than cocooning them in a nest like others would. They are known to use stealth, just like their siblings. Although not as strong as other castes, Runners are still strong enough to lift a full grown Human. Like other Xenomorphs, they're also known to attack the head of their prey with their pharyngeal jawed tongues, and are capable of spitting acid.

Runners are shown to be more animalistic in nature and are not the sharpest caste in the hive. They do have some intelligence, but not as much as their bipedal counterparts. The Runner on Fury 161 utilized hit and kill tactics, rather than capturing creatures and cocooning them in an established nest. They are smart enough to not harm any members of their own kind, especially hosts impregnated with larval Queens. This was seen when Ellen Ripley was in the medical bay of the Fury 161 penal colony. After the Dragon killed Chief Medical Officer Jonathon Clemens, it quickly turned to Ripley, who was horrified of the creature and despite its intimidating moves towards her, left her completely unscathed. It even tried to protect Ripley from Leonard Dillon who was trying to get her away from it while it was trapped in a corner.

Conversely, this same individual has also demonstrated a desire for revenge, even against those carrying unborn Xenomorphs. This was seen after it was drowned in hot lead and managed to survive. This led to the creature chasing after Ripley until she dowsed it in water from the sprinklers, causing it to explode via thermal shock.

TarkatanEdit

Audit2

The Tarkatan Xenomorph is a strain of Xenomorph born from a Tarkatan host. Although, by genetic identification, this strain is identified as "Tarkatan", this type is only one of three variations of this specific strain.[17]

This Xenomorph strain appears to be a bit more bulky and muscular than their wiry, lanky Human-spawned siblings. It is black, like them, but has a shorter head and a more impressive set of teeth, like its host. The Xenomorph also has arm blades, a trait taken from its host, though its blades are segmented and hooked at the ends. The primary difference between the three variations of the Tarkatan strain is the head. The primary variation's head is similar to the ridged head of the Warrior. The Acid variation is smooth-lined like the Drone caste, while the Konjurer variation's head bears a close resemblance to the larger crest of a Praetorian.

The Tarkatan Xenomorph appears to be able to adhere itself to surfaces like most of its species. Its most obvious and striking feature is its arm blades, which bear a resemblance to some Yautja weaponry. The Acidic variation of this strain is able to spew blood out from its body, while the Konjurer variation has the ability to summon Drones and facehugger "traps" on the battlefield.

Subspecies and other morphsEdit

Numerous types of Xenomorphs have been recorded which aren't the product of gene transference from a host. As a widespread species with fast reproduction, the emergence of a number of subspecies and mutations is to be expected; although some of them haven't evolved naturally, but were intentionally engineered by scientists.

  • Bodyburster: A rare neotenic variant that never matures past the chestburster stage, resulting in a giant worm-like creature.
  • K-Series: Also known as "Yellow Xenomorphs", due to the coloration of their skin. Created by Dr. Samuel Kadinski, they fought against the original Xenomorphs, but failed to defeat them.
  • Neomorph: A pale-white variant found on the mysterious planet where the android David conducted his research from 2094 to 2104. The life cycle of this subspecies is different, involving airborne spores rather than eggs and no facehugger stage.
  • Red Xenomorph: A naturally-occurring mutation; easily-recognizable for their red skin. A Red Queen Mother and her warriors tried to take over Xenomorph Prime, waging war against the black Xenomorphs. The "civil war" ended with the defeat of the red-skinned "rebels".
  • Tusked Xenomorph: Employed as "hunting dogs" by some Yautja clans, similarly to the Predator Hounds and Hell-hounds. They look similar to other Xenomorphs, but possess a pair of tusks, already present in the chestburster stage. They've been observed to be born from Human hosts, ruling out the possibility of being simply bred from a tusked species.

Culture and societyEdit

The Xenomorphs have a caste system similar to that of bees and ants. A major difference is that their caste system is far more complex.

It's believed that the Drones (in this instance used to indicate a "worker" caste, instead of mating-capable males) have the smooth cowl while the Warriors display the ridges. The Drones and Warriors have different tasks: Warriors defend the hive, and Drones hunt potential hosts, while some live only to protect the Queen, such as Hive-Warriors or Praetorians.

DroneEdit

The basis of any Xenomorph hive; the Drones are very much like worker bees or ants. Their main tasks are to keep the hive in good condition. Also, they seem to have the job of creating their nests with their own secretions.

They average in size at about 6–7 feet tall (~ 1.8 to 2.1 meters) standing on hind legs, and about 14–15 feet long (~ 4.2 to 4.6 meters), tail included. They have the basic body build of the Warrior, except that their dome is completely smooth, whereas the Warrior's dome is typically more ridged. Drones are smaller and somewhat more delicate than the Warriors, not considered quite as dangerous by Yautja standards, but striking fear into the heart of any Human.

Like all of their brethren, they have acidic body fluids, but only the Drone can spit this secretion onto prey over a short distance. Drones have an organ in their bodies that releases a sticky fluid that they can spit out of their mouth onto any surface. It can be used to harvest cocooned hosts for the Queen's facehuggers.

WarriorEdit

Warrior Xenomorphs - commonly known as simply Warriors - are the soldiers and protectors of the hive. They are all children of the hive's Queen, bigger and stronger than the Drones. The Drones are less deadly and somewhat less intimidating.

Warriors average in size at about 8 feet tall (~ 2.4 meters) standing on hind legs, and about 14–16 feet long (~ 4.2 to 4.9 meters), tail included. In most cases, the Warrior looks the same as a Drone, except that the dome on top of the head is generally ridged.

They may evolve into Praetorians, which may serve as the Queen's personal guard and potential successors. Typically, there are four of them at any given time. However, when the Queen wishes to watch them battle for her attention or increase protection in preparation for an attack on the hive, she will release pheromones which cause four additional Warriors to evolve into Praetorians.

PraetorianEdit

Praetorians ("Royal Guards"), are bigger and stronger than the Warriors and are seen to have a developing crown. Their primary role within the hive is to guard key locations of importance or interest, and, if nothing else, to protect the Queen herself. Most Praetorians can be found very close to the Queen's chambers. The physical features of the Praetorian are pristine and very similar to the Queen's: it has a crown-like head crest, large size, and great strength.

The Praetorian is said to be created by special eggs and facehuggers known as a royal facehugger (these are generally larger and a darker color than normal facehuggers), which carries a genetic code known as the Royal Jelly Line, which is passed from the Queen herself to the facehugger and embryo. However, there are cases in which the Praetorians evolve from the Warrior caste. The Queen selects a Warrior to become a Praetorian, and the Warrior is then attacked by fellow Xenomorphs from the same hive and banished. The Warrior must survive on its own for a long period of time. It grows and sheds, becoming approximately fifteen feet tall (~ 4.6 meters) and gaining its head crest. It returns to the hive as a worthy guard to the Queen.

Besides their guard duties, Praetorians may also act as the "princesses", or immature Queens of the hive, who can be promoted to Queens.[18] The Xenomorph known as "Number Six" started out as a Warrior and demonstrated the ability to mature into a Praetorian and later a Queen.[19] This rapid alteration is another evolutionary trait of the Xenomorph to ensure its very survival as a species. The Xenomorph Queen can lay specialized eggs that are bigger (like Queen egg cells in bees which are bigger than Drone cells), that upon hatching can carry on the species through making other hives after the new female cocoons into a Queen.

Some varying reports of Praetorians with massive shield-like growths on their forearms have been seen.

QueenEdit

Anguish

A Queen alien, attached to her ovipositor.

The Xenomorph Queen is the largest and most intelligent Xenomorph and can grow incredibly large, up to 100 feet tall (~ 30.5 meters) if given time. She lays many eggs that hatch to become the first stage of Xenomorph. It is unclear whether the Queen engages in combat outside of protecting her hive. The Queen is usually nestled deep within the hive, protected by Praetorian guards.

She has been known to display some logic-based intelligence, primarily in using simple Human technology such as lifts. She is the most dangerous of the hive, displaying extreme aggression and using her intelligence to devastating effect.

When attached to her egg sac (ovipositor), she is immobile and vulnerable to attack. When she removes herself from it, however, she can move surprisingly fast. She attacks with her four clawed arms, as well as her long, bladed tail. She has also been shown to use her main and inner jaws in combat.

Interestingly enough, it seems that the size of Queens varies. In one occasion, the Queen was shown to be maybe only twice the size of a Drone (this also may be due to her being so relatively young). In others, she is shown to be considerably larger - three or four times the size of a Drone. This could be explained in a similar fashion to an older Drone's ridged head, as the Queen in question was very old: although kept in a dormant state for long periods of time, she could have been alive for several millennia. Alternatively, she could have been an Empress. Queens usually stand around 15 to 20 feet tall on average (~ 4.6 to 6.1 meters).

As stated, Queens are created through royal facehuggers which produce Praetorians, or immature Queens. When a Queen dies or abandons a hive, a Praetorian may fully develop into a new Queen and take her mother's place. Whereas normal embryos adopt characteristics from their host, the royal facehugger's does not. The royal facehugger carries within it the Royal Jelly Line, which is a genetic code passed down from the Queen Xenomorph to her chosen offspring. The embryo is more or less a genetic copy of its mother and as such will not adopt the characteristics of the host, but will retain the physical characteristics of the Xenomorph Queen. Regardless of host, the Praetorian will appear nearly exactly the same as its mother when it fully develops into a new Queen. Because of this, it's often speculated that the Queen is the only "pure blooded" Xenomorph variety.

EmpressEdit

65920

Dr. Eisenberg stands in the guard of the alleged Empress

There is mention of a Xenomorph Empress as well. Dr. Eisenberg might have merely used the term "Empress" to refer to the Queen. However, the Empress is bigger than the average Queen, and might also represent a distinct caste.

Although very similar to a regular Queen, the Empress's main duty is to establish order on a planet with multiple hives. The only known differences between the two are their size: the Empress is substantially taller than a Queen, standing anywhere from 20 to 25 feet tall (~ 6.1 to 7.6 meters); and the fact that an Empress' crown has five points instead of the traditional three. It is possible that an Empress is simply the oldest Queen on a planet, and the physical differences are the result of aging.

It is also mentioned that after a hive grows to around 2,000 members, the younger Queens set out to establish new hives, and that if the Empress was to die, it would cause the younger Queens to fight over the new hive ruler. It's most likely that an "Empress" Xenomorph is merely a Queen that has dominated the other Queens in a hive. This would make the title "Empress" just that: a title.

Above the rank of Empress there is the Queen Mother: the single supreme ruler of all Xenomorph hives on all conquered planets; which resides on Xenomorph Prime, accompanied by a personal guard of Queen-sized Praetorians known as Palatines.

Other castesEdit

Other Xenomorph castes are rarely seen, and it's possible that not all hives have them, and/or that they prefer to stay hidden for the most part, and avoid venturing out of the hive or facing intruders.

One documented caste are the Workers, a.k.a. Weavers or "Albino Drones", due to their white coloration. These Xenomorphs are considerably smaller than regular Drones, standing between 4 and 6 feet (~ 1.2 to 1.8 meters), and are usually not confrontational. More-so than any other caste, they're primarily concerned with the maintenance and expansion of the hive's structure, and may also tend to the Queen. They're most notable for their extremely developed proboscis-like inner mouth, which is used to secrete the resin to build up the hive walls.

The Carrier caste and the Ravager caste are both large, specialized forms derived from Praetorians. The Carrier's function is to harbor, protect and transport facehuggers, which will cling to the protrusions on its dorsal spines, and may launch themselves at nearby creatures. The Ravager, on the other hand, is a purely offensive caste which seeks only to destroy opponents, regardless of whether they could make useful hosts or not. They're only really employed when the hive is at war.

A particularly dangerous, but seldom-seen possible caste is the Crusher. This massive, tank-like, heavily-armored quadruped is mostly known for its wide bulletproof cranial shield. Despite being as large as a Praetorian, it's capable of achieving great speed, lending support to the idea that it might represent a Praetorian matured from the "Runner" (Xenomorphs spawned from quadrupedal hosts, such as dogs). Another possibility is that the Crusher might represent a mutation, rather than a naturally-occurring caste.

Other less prominent castes include the Lurker: essentially a Drone which, as its name indicates, specializes in stealth tactics. The poorly-known Boiler and Spitter castes were encountered by the crew of the USS Sephora on LV-426; as was the afore-mentioned Crusher. Although most Drones can spit acid, the Spitter possesses specialized pouches on its head to store additional quantities. The Boiler, meanwhile, is probably one of the strangest castes: a deformed-looking alien whose suicidal attack consists of rupturing its own body and "exploding" in a rain of acid.

Although a few artificially-created individuals, such as the Rogue Xenomorph, have been referred as "king", the existence of naturally-occurring Xenomorph Kings is dubious, supported only by apocryphal sources.

HistoryEdit

XenomorphImageryLV223

The image of a Xenomorph visible on the walls of the Engineer's temple on LV-223, in 2093.

It is heavily implied that Weyland-Yutani's original synthetic android David was the chief designer of the first Xenomorph egg and therefore the creator of the species. However, there are no solid facts as to the origins of the Xenomorph species; instead, there are many theories which cannot be confirmed. They may be an artificially created species, or they may have evolved naturally on a planet very different from Earth.

It has been implied that the Xenomorph species derives from the Black Liquid: a living biological weapon created by the Engineers, and stored in special canisters inside a temple on LV-223, a moon of the gas giant Calpamos, in the Zeta Reticuli System. The Liquid was created to infect other life forms and either kill them or merge with their genetic structure, giving rise to new and extraordinarily hostile mutations. Simple worms mutated by this substance, for instance, developed into the Hammerpedes: a species which shares some traits with Xenomorphs, such as the acidic blood.

In 2093, the USCSS Prometheus arrived on LV-223 and the temple and the Black Liquid were discovered. The android David (built to be curious and Human-like) secretly infected Charlie Holloway with a drop of the mutagen, and Charlie then impregnated Elizabeth Shaw; resulting in a large facehugger-like lifeform known as the Trilobite. Elizabeth, in pain from the creature growing within her, then removed the lifeform by entering the automated surgery table on-board Meredith Vicker's exclusive ship. The lifeform later encountered an Engineer and ensnared him much like a facehugger; thus, creating the Deacon which highly resembles the Xenomorphs, albeit with some differences, such as the pointed head and absence of a tail.

By the next year, David had hijacked an Engineer ship and traveled to an unnamed planet believed to be their homeworld, where he decimated the Engineers' settlement by unleashing the Black Liquid upon them and observed as the Liquid took over life forms native to the planet. Over the next ten years, David experimented with combining these native life forms with material taken from the bodies of Humans and Engineers alike. Meanwhile, on the planet's wild ecosystem, the first Xenomorph variety was already starting to develop, known as the Neomorph.

At last, David's research led him to create a batch of genuine Xenomorph eggs, containing actual facehuggers. David knew he needed Human hosts to eventually gestate the Xenomorphs to fabricate his fantasy of becoming a god and creating something even better than his own makers, and this flight of fancy came true when the crew of the USCSS Covenant landed on the planet and one of the facehuggers impregnated Chris Oram, with the resulting chestburster developing as a modern-looking Xenomorph; possibly the first of its kind. The Xenomorphs have come to be known as "the Perfect Organism", fulfilling David's aspirations.

Thus, the chain of "uplifting" can be summarized as the following.

--> Engineer --> Human --> AI Synthetic --> Xenomorph.

However, this is heavily contradicted by the fact that the Xenomorphs are known to be a pre-existing species that was traditionally bred, reared and hunted by the Yautja intentionally for sport: a tradition that goes back thousands of years and has been practiced on Earth as well as other planets. Unless the Yautja or another species has found a way to time-travel and brought Xenomorphs to the distant past, this remains incompatible with the idea of Xenomorphs having been genetically-engineered by David.

Another fact that casts doubt about the idea of David's creation being the first Xenomorph is that images representing what appear to be modern Xenomorphs were already present inside the walls of the Engineers' temples when David and the other Prometheus crewmembers arrived in 2093. The presence of these images could suggest that the Black Liquid was originally derived from the Xenomorphs, rather than vice-versa. In that case, specimens like the Deacon, the Neomorphs and David's Xenomorph could represent various stages of regression to a more ancestral form.

K-series-battle

Regular Xenomorphs (black) engaged in war against the Human-created "K-series" Xenomorphs (yellow).

In any case, it is certain that there is some kind of link between the Xenomorphs and the Mala'kaks, a.k.a. Engineers or "Space Jockeys". The Xenomorph could be the result of genetic manipulation by the Mala'kaks, created as a terraforming mechanism about ten million years ago, which went terribly wrong. A Mala'kak ship found as a derelict on LV-426 in 2122 was shown to have an entire chamber filled with Xenomorph eggs, apparently held in stasis for a long time. It's possible that the Mala'kaks used the Xenomorphs as weapons and/or research subjects, but the details are still unknown.

Another idea is that the Xenomorph were the alpha predators of their own ecosystem on a nightmarish and harsh planet (assumed to be Xenomorph Prime, but there is no solid evidence). Without their native ecosystem to keep them in check, they developed into a separate dominant species. The Mala'kak, the Yautja, Humans and the Reapers began showing interest and started using them as means of sport, terraforming mechanisms, biological weapons, culinary delicacies (in the case of the Reapers and a giant unnamed reptilian race) and scientific experiment subjects, with various results. Experiments such as the K-Series, the Rogue Xenomorph, the Xenoborgs and the White Hybrids; as well as natural mutations such as the Red Xenomorphs have proved again and again how dangerous the species' biological plasticity can be; and yet, the victories of the traditional black-skinned Xenomorphs against many of these challengers (such as the Reds, the K-Series and the Rogue) have shown that the "Perfect Organism" moniker is still appropriate.

AppearancesEdit

Xenomorph-design

FilmsEdit

  • Alien (1979)
  • Aliens (1986)
  • Alien³ (1992)
  • Alien Resurrection (1997)
  • Alien vs. Predator (2004)
  • Aliens vs. Predator: Requiem (2007)
  • Alien: Covenant (2017)

LiteratureEdit

  • Aliens: Earth Hive (1992)
  • Aliens: Nightmare Asylum (1993)
  • Aliens: The Female War (1993)
  • Aliens: Genocide (1993)
  • Aliens vs. Predator: Prey (1994)
  • Aliens: Alien Harvest (1995)
  • Aliens: Rogue (1995)
  • Aliens: Labyrinth (1996)
  • Aliens: Music of the Spears (1996)
  • Aliens vs. Predator: Hunter's Planet (1997)
  • Aliens: Berserker (1998)
  • Aliens vs. Predator: War (1999)
  • Aliens: Original Sin (2005)
  • Aliens: DNA War (2006)
  • Aliens: Cauldron (2006)
  • Aliens: Steel Egg (2007)
  • Aliens: Criminal Enterprise (2008)
  • Aliens: No Exit (2008)
  • Alien: Out of the Shadows (2014)
  • Alien: Sea of Sorrows (2014)
  • Alien: River of Pain (2014)
  • Alien: Invasion (2016)
  • Alien vs. Predator: Armageddon (2016)
  • Aliens: Bug Hunt (2017)
  • Alien: The Cold Forge (2018)
  • Alien: Echo (2019)
  • Alien: Isolation (2019)
  • Alien: Prototype (2019)
  • Aliens: Phalanx (2020)

Video gamesEdit

  • Aliens versus Predator (1999)
  • Aliens versus Predator 2 (2001)
  • Aliens versus Predator: Extinction (2003)
  • Aliens: Extermination (2006)
  • Aliens vs. Predator: Requiem (2007)
  • Aliens vs. Predator (2010)
  • Aliens: Colonial Marines (2013)
  • Alien: Isolation (2014)

Tabletop gamesEdit

  • Aliens Adventure Game (1991)

ComicsEdit

  • Dark Horse Comics

GalleryEdit

Life stagesEdit

Hive castesEdit

Host-based strainsEdit

Mutations and artificial variantsEdit

OthersEdit

NotesEdit

Xenomorph-HRGiger

H. R. Giger's design concept.

  • The image that would eventually become the Xenomorph's design was originally featured in H. R. Giger's book Necronomicon, named after the eponymous forbidden grimoire from the stories of H. P. Lovecraft.
  • The Xenomorph's method of reproduction is rather reminiscent of that employed by the Ixtl, a species featured in the novel The Voyage of the Space Beagle, which predates the Xenomorphs by almost 30 years. The first Alien film has even been accused of plagiarism regarding the book, although the producers denied any possible influence or connection.
  • Another possible inspiration for the Xenomorph is the small deep-sea crustacean Phronima, which is physically similar to some Xenomorphs (particularly the Xenomorph Queen) and is also an endoparasitoid, laying its eggs inside the body of deep-sea salps and killing them from the inside, after which the crustacean continues to inhabit the salp's hollowed body.
  • Within its franchise, the Xenomorph has been referred to as "Kane's son", a "creature", a "serpent", a "beast", a "dragon", a "monster", a "nasty", a "thing", a "bug", among others.
  • Besides merging with the Predator franchise, the Xenomorph species has been featured in a myriad of other science-fiction, superhero and comedy franchises.
    • It appeared in an episode of the cartoon comedy Animaniacs called "Space Probed".
    • Xenomorphs make frequent appearances in the comic strip Brewster Rockit: Space Guy!, with the most prominent Xenomorph character being Philbert, the "son" of human engineer Cliff Clewless, who figures among the few known survivors of a facehugger implantation.
    • A Xenomorph named Heinrich serves as the final boss of the Nintendo 64 game Conker's Bad Fur Day.
    • Xenomorphs have been fought by several DC Comics heroes, including Batman, Superman and the Green Lanterns.
    • The Xenomorph Queen has also briefly appeared in an episode of the comedy series Family Guy.
    • The Tarkatan Xenomorph is a strain spawned from the Tarkata of Mortal Kombat. It is featured in Mortal Kombat X.
    • A small Xenomorph appears as a dog-equivalent on Planet 51 and is shown to urinate acid.
    • They appeared in the comedy show Robot Chicken.
    • A singing and dancing alien bursts out of John Hurt's chest in the 1987 sci-fi comedy Spaceballs. Unlike most chestbursters, it possessed fully-developed legs and red eyes.
    • Xenomorphs have also made cameos in some Star Wars material, though they are not canon.
    • According to Derrick J. Wyatt, the Nemetrix from Ben 10: Omniverse can accept Xenomorph DNA.
  • Additionally, the design of the Xenomorph has become so iconic that it inspired numerous others.
    • The Xenos from Alone in the Dark are named and designed after them.
    • In an episode of Chip 'n' Dale Rescue Rangers, the Rescue Rangers watch a science fiction movie with an alien resembling a Xenomorph.
    • In the Dragon Ball Z series, the first main villain Frieza has a third form transformation that resembles a Xenomorph, particularly sharing its signature long cranium.
    • Some fans have noted similarities between Xenomorphs and the Propagators found on the Ragnarok in Final Fantasy VIII. It is possible that the Xenomorphs served as the inspiration for this creature, which is territorial, carnivorous, and is found only in remote locations in space.
    • In Lilo & Stitch: The Series, Experiment 627 is shown to have an extendable appendage in his mouth similar to the Xenomorphs.
    • The Xenomorph's design has inspired the creation of the Metroid villain known as Ridley, which is a reference to Alien's director Ridley Scott. They also bear a resemblance to Space Pirates, the antagonist species in the Metroid game series.
    • The Space Quest series of science fiction parody adventure games, feature several references and homages to the Xenomorph. In Space Quest II, a "spiny alien" resembling a Xenomorph with big red lips appears; if it catches the player, Roger Wilco, it kisses them and they later die of a chestburster. In Space Quest V, a creature similar to a facehugger is found in a garbage load and adopted by Roger. Its urine, in reference to its blood, is highly acidic. In Space Quest VI, a Xenomorph is shown in a "cameo" easter egg, sneaking into the shuttle of a parody of Ellen Ripley: Ellen Wrigley.
    • The Pizza Monsters from the 1987 Teenage Mutant Ninja Turtles series are clearly designed after the Xenomorphs; as are the Squirrelanoids from the 2012 series.
  • In Aliens, the Xenomorphs seem to shake their heads slightly before attacking their prey.
  • The fact that they have no visible eyes was conceived by Giger in his original design, because he felt that it made the creatures much more frightening if one could not tell they were looking at them.
    • In the original Alien film, the top of the creature's head was semi-transparent, with empty eye sockets of human appearance visible within. This element was dropped in later movies, but reused for the Predalien design, on the front portion of its skull.
    • In Alien³, a fish-eye lens represented the Runner's sight, but it is unknown if this is really how it sees or simply a filmed representation of the creatures' sensory perception.
    • The idea that a Xenomorph may have eyes deep inside its skull is seemingly lent support by early models and toys of the Warrior Xenomorph, while Alien was still the only existing movie in the timeline. These showed an actual, physical, humanoid skull built under the smooth carapace, with the smooth top working like a one-way visor.
    • In the 2010 Alien vs. Predator game, it is mentioned in one of the Marine audio tapes that Xenomorphs have vision. The game implies that the Xenomorph sees using its attack tongue, though this may be for gameplay purposes rather than factual information.
    • In the novelization of the movie Alien, the creature is held mesmerized by a spinning green light for several minutes.
  • The Xenomorph has been portrayed in noticeably different ways throughout the film series. Much of this was due to the continuing advancements made in the field of special effects, technology, and techniques used to bring it to life.
    • In the original Alien film, and in the sequel Aliens, Xenomorphs are depicted as tall, slender creatures with a roughly Human biomechanical design. The chest area appears to be rib cage-like in design.
    • In later films, such as Alien: Resurrection and Alien vs. Predator, they are depicted as being shorter and bulkier organisms, as well as being more quadrupedal, portrayed by either stuntmen in suits for close-ups, or computer-generated imagery for their full form.
    • In Aliens, Xenomorphs are depicted as having ridges along their cranium, while in all other films they have smooth cowls covering their skulls. It was speculated in the Aliens bonus DVD that this was due to these Xenomorphs having had more time to mature, compared to the Xenomorphs in the other films. In the comics and various video games (Aliens vs. Predator: Extinction, Alien vs. Predator (SNES), Aliens vs. Predator 2), this was depicted as one of the visual differences between the Xenomorph Drone and Warrior castes.
    • In Alien and Alien³, the Xenomorph has six fingers, with the index and middle fingers conjoined into one digit, ring and little fingers also conjoined, and thumbs on both sides. In Aliens, the Xenomorphs are shown with five fingers, with the second thumb missing. In Alien: Resurrection and Alien vs. Predator, the aliens have four fingers, though the middle two appear to be a fusion of two digits. No explanation is given in the films for the fluctuating number of digits, although the creature's well-known genetic plasticity probably accounts for that.
    • Originally, the Xenomorph's tail was roughly the length of the rest of its body, with a small, almost surgical stinger-like barb on the end; but from Alien³ onward, the tail has extended in length and features a large, knife-like blade at the tip. In Alien: Resurrection and Alien vs. Predator, the tails have also supported a ridge of spikes right before the blade. This was introduced in Alien: Resurrection to help them swim convincingly, and was left intact in Alien vs. Predator. The tail itself is shown to be of incredible length during Alien vs Predator, measuring almost its full body length.
    • The original shooting script for Aliens featured a scene in which Lieutenant Gorman was "stung" by a Xenomorph's stinger. He was not killed, merely stunned, and the barb remained lodged in his shoulder. The novelization also included this scene, though the final cut of the movie does not. This attribute is used later on in various games.
  • In a cut scene in Alien (included in the Special Edition), Ripley found two of her cocooned colleagues actually being turned into Xenomorph eggs. This suggests that Xenomorphs can convert Humans into eggs when there is no Queen, although this may have been scrapped as many other features of the Xenomorphs were in later movies (such as the transparent skulls and empty eye sockets). In the book, it's described how the Drones are able to implant a fetus in up to four hosts, thereby creating enough Drones and Warriors to start a hive with.
  • "On the pH scale, [the alien blood] would probably rank at a devastating negative four or lower", a previous author claimed. This is theoretically possible, despite the fact that pH is the minus logarithm of the free H-ions' concentration. To put this into perspective, water has a neutral pH of 7 and our stomach acid has a pH of 1, which would lie at the very bottom of the 1 to 14 scale. Attempts to discredit such a claim are challenged indirectly by chemists who have found that mixing antimony pentafluoride with hydrofluoric acid can produce a solution with a pH of -31. This therefore would render it 100,000 billion, billion, billion times more potent than stomach acid. It should be noted, however, that this acid is basically formed by mixing two incredibly strong acids together in the first place, which interact to become even more acidic. Though former theories have in fact stated that two potent chemicals (with perhaps some biological catalyst) may mix to create the acidic blood seen. Perhaps the strongest 'solo' acid would be the boron-based carborane with a pH of -18. Yet due to the structure of carborane, the H+ ions, which create the phenomenon known as acidity, are shared so efficiently between molecules that it would have no corrosive effects at all. Hence despite challenges it would appear even that which is known on Earth certainly leaves scope for the incredible properties of the aliens' acidic blood. It may also go without saying that different environments in other worlds could evolve "acid blood" that could also carry whatever nutrients that the Xenomorph needs.
  • In the first movie, it appeared that the eggs could sense when another creature crossed into some form of mist covering their nursery area. It's a widely accepted hypothesis that this was a containment field to keep the eggs dormant (this same mist has been used as such in Aliens Vs. Predator 2 video game), put in place by a Mala'kak, a.k.a. "Space Jockey". When this mist was broken, the facehuggers appeared to be alerted, and went on the search for the host.
  • In the video game Alien Vs. Predator 2, one of the alien missions requires the player to find a source of food in order for the chestburster to advance to its Drone phase. At the end of the level, a short cut-scene indicates that the chestburster consumes a house cat in a carrier. The scene does not show what happens during the change in the life cycle.
  • Though maintaining the basic design shown in the Aliens vs. Predator video games, numerous artistic liberties were taken in the film portrayal of the Predalian. Or rather, would have been taken. One abandoned concept was to have the Predalien reproduce by injecting victims with "DNA acid" through its tail, causing the victim to swell and explode.
    • Another is the Predalien's inherited tendency to skin victims. This was probably dropped because skinning victims isn't something that comes instinctively to Predators, but rather a learned behavior.

See alsoEdit

References Edit

  1. Latin: meant as "murderous thief" (Alien Quadrilogy DVD)
  2. Latin: meant as "foul tongue from Acheron" (comic books)
  3. Alien: Sea of Sorrows
  4. James Cameron, director's commentary, Aliens, Alien Quadrilogy boxset
  5. Alien: Resurrection
  6. Aliens vs. Predator: Requiem
  7. Alien Book 2: Nightmare Asylum
  8. As seen in the movie Alien³ and the book Aliens: DNA War
  9. Alien vs. Predator Volume 1 comic
  10. Aliens, Director's Cut
  11. Aliens: Terrordome mini-comic
  12. Aliens video game, 1990
  13. Aliens: Colonial Marines
  14. Alien vs Predator: Extinction
  15. Alien³ extended version
  16. Alien novelization by Alan Dean Foster
  17. Mortal Kombat X
  18. Alien vs. Predators: Extinction
  19. Aliens Vs. Predator 3 video game

External linksEdit

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