Flatcat

In Robert A. Heinlein's science fiction novel "The Rolling Stones", flat cats are a species of emotional symbiotes native to Mars, with very adaptive metabolisms.

They are small, furry, omnivorous, non-predatory, and flattish, and they purr, and make their potential predators sufficiently happy to tolerate their presence, and perhaps even to feed them.In the absence of food, they estivate (or hibernate) by becoming inactive and reducing their metabolism to extremely low levels.This is a survival mechanism that might very well be expected of a species from a resource-poor and environmentally strenuous planet such as Mars.When food becomes more abundant, they reproduce rapidly to take advantage of the more favourable conditions.

Because of the latter, flat cats are widely believed to have been the inspiration for "The Trouble with Tribbles", an episode of the original "Star Trek" television series, in which tribbles display similar characteristics. However, in David Gerrold's account of writing the episode, he states that this was not the case.

In David Alexander's authorized biography of Gene Roddenberry, "Star Trek Creator", he writes that Desilu's research department had discovered the similarity and notified Heinlein. According to some of Heinlein's personal papers, he felt that at some time in the past he might have considered legal action to block the show or force changes, but was too old now to really care. He also wasn't sure he could really say the concept originated with him. It may well have originated with the story "Pigs is Pigs" (1905) by Ellis Parker Butler about proliferating guinea pigs. Gerrold later wrote (in his book about the writing of "The Trouble with Tribbles") that the matter was easily settled and Heinlein requested an autographed copy of the shooting script, which Gerrold was thrilled to provide.