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). Many ship’s cats will refuse to exit the ship on all but standard atmosphere worlds (or in standard pressure regions of thin or dense atmosphere worlds) but have natural filters for tainted atmospheres. They have been thoroughly bred and engineered to not chew on wires or otherwise ruin sensitive systems and become temporarily infertile while in jumpspace, remaining so for several days after breakout. Most breeds can distinguish ship’s crew from passengers and will stay away from the latter if they seem to be the type who would not appreciate cats.

Ship’s cats are kept for companionship and to hunt vermin that get on board. Some Vargr keep ship’s cats for their company, especially lowborn Vargr without many friends. Aslan instinctively see ship’s cats as competitors for the same prey and so rarely keep them. Some breeds, developed in the Third Imperium before the Psionics Suppressions, are psionic, favouring teleportation the way sophonts favour telepathy. These add the Psionic (9) trait and Teleportation 2 skill, and rarely teleport with equipment; collars are left behind but implanted transponders (standard for ship’s cats, to make sure they are aboard when it is time to leave port) will teleport. They are known for teleporting through walls (never into vacuum and are able to escape sudden depressurisation of a compartment this way), disappearing around corners or behind furniture and generally going anywhere in a ship they want to.