Tribble crossection

The inner workings of a Tribble

Tribbles (Polygeminus grex) are a species of small alien lifeforms which do little more than eating and reproducing constantly. These furry, rounded herbivorous creatures with no visible features come in several shades of brown, grey, cream, white or pink; can be from about ten to thirty centimeters long and move around by crawling rapidly or rolling.

Behavior and ecology

Tribbles are physically harmless, but can be quite a problem due to their perpetual hunger and fast reproduction, as they reproduce asexually and are born pregnant. They emit purring sounds and are known to have a tranquilizing effect in the nervous system of humans and possibly other species. Klingons on the other hand detest Tribbles and consider them a nuisance and a pest; causing Tribbles to become scared and agitated whenever they approach a member of the Klingon species. Captain Kirk once took advantage of this and successfully used a tribble to identify a Klingon spy disguised as human.

The Tribble homeworld is called Iota Geminorum IV and is also home to reptilian predators which keep the population in check. Once off their homeworld, however, they can reproduce uncontrollably and become an invasive species. Genetic engineering was once used to attempt to make the tribbles safer by eliminating their ability to reproduce. At first, the affected tribbles appeared to be increasing in size, but it was soon discovered that they were still reproducing, but remaining together and forming tribble colonies. The situation was solved by Dr. McCoy, who found out that neo-ethylene would allow the tribble colonies to break apart and also cause the individual tribbles to have a slower metabolic rate.

In spite of this, in some point after these events the Klingons decided to end the tribble "pest menace" by bombarding the tribble homeworld, driving the species extinct. When the crew of space station Deep Space 9 traveled to the past to prevent the assassination of James T. Kirk by a Klingon agent, they also managed to bring a few tribbles to the 24th century, successfully reintroducing the species.


Tribbles were first encountered by Humans in the early 2150s, when Denobulan doctor Phlox brought a small number aboard Enterprise NX-01 as food for his pets. (ENT: "The Breach")

The tribble was later encountered by the Federation aboard Deep Space K-7 in 2268, when Cyrano Jones brought a small number aboard to trade. However, a single tribble brought aboard the USS Enterprise quickly multiplied to 1,771,561. The tribbles were instrumental in foiling a Klingon plan to poison a shipment of quadrotriticale intended for Sherman's Planet, when tribbles that had fed on the grain were found dead. (TOS: "The Trouble with Tribbles")

At the same time, the crew of USS Defiant, transported through time by Arne Darvin, prevented him from using a tricobalt device hidden inside a tribble to kill James T. Kirk. (DS9: "Trials and Tribble-ations")

Tribbles were an ecological menace for the Klingons, to whom a tribble would react violently. The Klingons first attempted to breed a predator to eliminate the threat. The glommer was used only once, in 2269, aboard the USS Enterprise, and proved unable to deal with the large number of tribbles aboard. (TAS: "More Tribbles, More Troubles")

During this time, Cyrano Jones attempted to genetically engineer the tribbles so that they could not reproduce. As a result of his dabbling, he deemed them to be "safe" so as to be compatible with humanoid ecologies, making them "great pets and profitable, too." Unknown to Jones, at the time, and as was later discovered by Doctor Leonard McCoy, Jones' genetic engineering was described as being "very slipshod," as the resulting tribbles appeared to grow in immense size, in place of rapid breeding. McCoy later discovered that the so-called "giant tribbles" really were not as they appeared, but rather colonies of tribbles. McCoy was able to remedy the situation by giving them "a simple shot" of neoethylene, which caused the tribble colonies to break down into their individual units with a slower metabolic rate, and finally becoming "safe tribbles". (TAS: "More Tribbles, More Troubles")

The Klingons' final solution to the tribble menace was to wipe the species out entirely. Klingon warriors were sent to hunt them down throughout the galaxy, and the tribble homeworld was obliterated in the late 23rd century. When told of this, Odo dryly remarked "another glorious chapter in Klingon history. Tell me, do they still sing songs of the Great Tribble Hunt?" (DS9: "Trials and Tribble-ations")

In spite of the destruction of their homeworld, many humans continued to have the small creatures as pets from late 23rd century, well into the late 24th century, as several children aboard the USS Enterprise-D appeared to have them as pets in 2364 and 2371. (Star Trek III: The Search for Spock, Star Trek Generations)


Tribble information

Information about tribbles was displayed by the computer in Keiko O'Brien's schoolroom on Deep Space 9 in 2369. (DS9: "A Man Alone", "The Nagus") Tribbles were displayed in an LCARS graphic in one of the USS Enterprise-D's science laboratories when the ship crash-landed on Veridian III in 2371. (Star Trek Generations)

DS9 Promenade infested with tribbles

DS9 Promenade

Tribbles were reintroduced into the 24th century when Captain Benjamin Sisko and his crew brought at least one of the creatures back to 2373, following a time-traveling visit to the tribble-infested space station K-7 of 2268. The promenade and Quark's bar on Deep Space 9 were subsequently overrun with the creatures. According to Captain Sisko, the Federation's Department of Temporal Investigations was not told about the reintroduction of the tribbles because "they didn't ask". (DS9: "Trials and Tribble-ations")

Miles O'Brien later recalled seeing the tribbles on the Enterprise with Julian Bashir when he was leaving Deep Space 9 at the end of the Dominion War. (DS9: "What You Leave Behind")


  • Star Trek - "The Trouble with Tribbles"
  • Star Trek: The Animated Series - "More Tribbles, More Troubles"
  • Deep Space Nine - "Trials and Tribble-ations"
  • Star Trek Into Darkness



File:180px-Tribbles on Earth.jpg
  • They are similar to the Martian Flat Cats from Robert Heinlein's The Rolling Stones. Writer David Gerrold, who created the Tribble species, was unaware of that at first, but when he found out about the book he asked for Heinlein's permission, which Heinlein granted in exchange for an autographed copy of the episode's script.
  • In the book Evolving the Alien: The Science of Extraterrestrial Life, a.k.a. What Does a Martian Look Like?, Dr. Jack Cohen and Ian Stewart surprisingly elect the tribble one of the most realistic alien species in Star Trek and describe a thoroughly detailed alien ecosystem scenario to justify how such a creature could have evolved.
  • The sounds of the tribbles came from altered dove coos, owl screeches, and empty balloons.
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