Spock

Spock was a female cat that was likely the pet of a crew member on the. She was apparently impregnated by another cat while onboard the ship.

Captain James Cutter thought that Spock and her pregnancy was a sign of good luck. Nurse Hershey had a feeling that Spock intended to give birth in her bed.

Trivia

 * Spock may be a reference to Jonesy, another cat that lived on the UNSC Pillar of Autumn.
 * Spock is most likely a reference to the Vulcan Star Trek character of the same name, Mr. Spock.
 * It is also Likely that the Cat is a reference to both Star Trek's Mister Spock, and also to Lt. Commander Data's Cat from Star Trek: the Next Generation.