A cat, hare, or rabbit. (Irish, pus, a cat.) It is said that the word, applied to a hare or rabbit, is from the Latin lepus, Frenchified into le pus. True or not, the pun may pass muster.
Oh, puss, it bodes thee dire disgrace, When I defy thee to the race, Come, `tis a bet; nay, no denial, I'll lay my shell upon the trial.
The Hare and the Tortoise.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894