Bio-raptor

The bio-raptor is a highly aggressive, carnivorous creature that inhabits the barren desert planet of M6-117. Their unique physical structure has made them efficient killing machines and the ultimate predator of their homeworld. The bio-raptors are the monsters that John Riddick and the crew of the Hunter-Gratzner must escape from, in the 2000 science fiction film Pitch Black.

M6-117
M6-117 is a desert planet in the fictional world of the Chronicles of Riddick Series, part of the M-344/G solar system. It is mostly a barren planet, in a system of three stars. Because of this, the planet is almost constantly in daylight However, every 22 years, when the orbiting planets in the M-344/G system block the three suns, there is a rare total eclipse. The pitch black darkness allows bio-raptors, being photophobic creatures, to roam the planet. The effectiveness of these animals as predators has wiped out all other organisms to live in M6-117, creating a mass extinction of all life, leaving them as the only living inhabitant of the planet.

Habitat
Bio-raptors (being light sensitive creatures) live in deep dark caves, avoiding of any sunlight. During the total eclipse of the suns, the bio-raptors emerge and fill both the sky and land of the desert planet, preying on any animal that comes their way.

Physical Appearance
Adult bio-raptors are large, winged predatory creatures. Their heads are shaped like a steel spinning top (extending left, right and upward; the upward extension is sharp almost like a long knife or guillotine). The head is complete with a set of large teeth, mostly incisors. bio-raptors do not have eyes or a visible nose (though it is known an olfactory system is present due to their acute sense of smell).

Their body is similar to that of dragons, though instead of having six appendages, they only have five: a pair or wings on their back, a pair of limbs (each with manus or talons) and a sharp two-tipped whip-like tail. Their manus are composed of four fingers, including an opposable thumb, each with a razor-sharp claw. The middle or palm of the manus also has an opening for a long retractable claw. The limbs and wings can interchangeably be used for walking, depending on which appendage is being used.

Physiology and Anatomy
The extensions of their skull can stretch out to more than six feet, and is implied to be more dense than human bones. There is no mention of the function of the extension pointing upward. It may be either a weapon, or because it slightly curls backward, it could be a counter balance to the heavier anterior facial structure.

The bio-raptor has no eyes, so it relis on it’s other heightened senses to search for prey. To navigate, they use their biosonar skill, or echolocation, much like bats. The sound is emitted from their mouths and received by their ears, located on each side of their extended skull. Because the ears are so far apart, the interpretation of their echolocation can enable the bio-raptor see a much wider field. However, this wider range also creates a blind spot directly in front of their head.

bio-raptors also use their acute sense of smell to locate prey, notably with how they can smell a small amount of blood even from a distance, like a shark. This implies that their olfactory sensors, though not outwardly visibly, are actually very sensitive. It is possible, though unconfirmed, that the extended structure of the skull allows the nostrils to expand to a certain length, allowing for the better sense of smell.

bio-raptors use an arsenal of tools to kill their prey. They have a set of long sharp incisors with a wide jaw, big enough to swallow a human head and decapitate it. Their claws can also be used to grab on to prey, and the retractable claw serves as an extended weapon. Their long two-tipped tail is also used to injure or grab on to prey.

The bio-raptors, amidst all their evolutionary advancements, also have some notable weaknesses. The most apparent is their photophobic nature, or their negative reaction to light. Photophobia is commonly associated with abnormal functioning or sensitivity in the eyes, but because bio-raptors have no eyes, their photophobia can be traced to an issue in their nervous system. This is observed when a flashlight is used on a bio-raptor, producing corrosive effects on its skin. Another weakness is in the strength of their skin, which is relatively more fragile than their hardened skull. This becomes apparent when John Riddick is able to easily kill a bio-raptor by slicing its abdomen, allowing its intestines to spill out. Though it isn’t mentioned, their weaker internal structure might be caused by the lack of nutritional protein due to the scarcity of food in their homeworld.

Life Cycle
The bio-raptors are presented in the planet M6-117 in two major forms, some in an (assumed) younger stage, while the most in their adult phase, nicknamed “big boys”. It isn’t explicitly identified whether the two are of the same species, but the similarities seem to make that implication.

The younger stage bio-raptors are much smaller (the size of a predatory bird) than their adult counterpart, though they do seem to possess almost the same skills. The younger bio-raptors, individually, cannot kill a human, but typically flying in a flock, can do considerable damage. They are also able to tolerate exposure to light more, seeing as how they can start flying out into the desert just before the eclipse.

The adult bio-raptors, or “big boys” are much larger, and capable of killing humans individually. They are also stronger, and more aggressive, however are more sensitive to light. It isn’t known what the bio-raptors do during the 22 year gap between the eclipse, though it is assumed they hibernate in order to save energy for the next eclipse.

Behavior and Social Interaction
Bio-raptors seem to be non-sapient, incapable of higher brain processing or sophisticated communication with other bio-raptors. The fact that they have wiped out all other forms of life in their planet, without understanding the possible repercussions, supports this non-sapient level of intelligence.

In hunting, younger bio-raptors fly together, sometimes being more than a thousand in a flock. Collectively, they can be as deadly as an adult bio-raptor, capable of cutting humans in half and lifting them through the air. Adult nio-raptors seem to work more individually, though it isn’t unheard of to be attacked by two or more at a time, depending on the amount of food available.

There is no definite culture or hierarchy among the bio-raptors, though it is possible that some level exists, since they seem to be capable of organized attacks.

Cannibalism
The bio-raptors' excessive hunting and predation has caused mass extermination of the other life forms in M6-117. Due to this lack of food sources, bio-raptors are known to engage in cannibalism, attacking and eating the weaker or younger bio-raptors. Even when there are still some humans to prey on, some stronger bio-raptors still choose to attack each other bio-raptors, suggesting that their hunger has reached a very extreme state.

Trivia

 * The sound waves emitted by the bio-raptors used for echolocation are audible to humans, which means its biosonar frequency is likely within 20-20,000 Hz (the range than at average adult human can hear).
 * Bio-raptors's blue-colored blood may be related to M6-117's lower oxygen atmosphere. It is likely that bio-raptors have hemocyanin, an alternate respiratory protein to hemoglobin (used for oxygen transportation) commonly found in crustaceans that live in low oxygen pressure environments. Interestingly, hemocyanin causes the color of blood to turn blue-purple.
 * It is unknown how long the eclipse lasts in M6-117.
 * The giant bones scattered in the M6-117 desert imply that a similar Whale-like terrestrial species once inhabited the area, though died out due to the Bio-raptor attacks.
 * There is one living organism that has managed to evade extinction on M6-117. These are the "glow worms" which emit a bright blue light (which was found and used by Frye, Jack and Imam while hiding in a cave). It is implied the glow worms survived because of this light-emitting characteristic, becoming unattractive prey to the photophobic bio-raptors.