While some early Terrans engaged in uplift of dolphins, others engaged in a different sort of genetic tinkering, that of ship’s cats. As JTAS 04 (p126) notes:

Terran cats have been aboard ships since before the Solomani discovered jump drive but ship’s cats are specifically bred for life aboard ship. They can sense pressure differentials and electric fields, which can help find problems in ship systems and in the event of depressurisation will instinctively seek out pressurised areas or enter rescue balls (which they sometimes inhabit for no apparent purpose beyond fun). Certain breeds can survive a short time in vacuum (so long as they are in contact with a surface to draw heat from) and in distress are able to operate simple airlock controls to get back inside (they never do this when in normal atmosphere).

In the days before the Psionics Suppressions, experimentation included cats with psionics as well. One rather obscure but tenacious breed is the “Crescent Cat”. While these cats always breed true with one another, thanks to an unexpected quirk of their epigenetics, they can spontaneously emerge from seemingly normal ship’s cats.

The Crescent Cat is characterized by its purple fur leading some to wonder if Zhodani ziavbor DNA has been included. (JTAS 04, p 128). Every cat has a white crescent somewhere on its body, not always in the same place, leading to their name. Unlike “normal” teleporting Terran based cats. The crescent variety appears to be more powerful psionically with a greater range of abilities. They are able to teleport quite adeptly, just like their brethren (JTAS 04, p127). They also appear to have a basic telepathy and light telekinesis they use to throw switches and open containers. They have a special talent to detect psionic ability in others. If bonded to an individual or crewmember they get along quite well. For anyone else, they respond harshly. It is though that perhaps these cats were breed specifically to detect Zhodani spies.

There is some evidence that latent genes passed down from parents can be activated for new offspring in the presence of psionic activity. It could be the cats are attracted to it. Crescent cats are solitary in nature and tend to want to be the only cat on a ship for a certain size. Very large ships might have more. It is really up to the cats as they are hard to remove once they have settled, teleporting away when confronted, and they are telepathic enough to see things coming. Male cats are more likely to roam ship to ship looking for mates, while the females tend to stay put. Kittens grow fast and will usually leave the ship after 8 months of growth unless they happen to form a particularly strong bond, though this is rare as the mother usually already has a bond with the “best” subject.