A rabbit is a small herbiverous quadruped, generally living under ground in burrowed tunnel-systems. Introduced to England by the Romans, rabbits then died out after the Romans left England. They were then re-introduced from France after the Norman Conquest, and the Domesday Book records established warrens of rabbits as a bankable resource of the king. They have always been seen as ready source of food and fur, provided you can catch them.
Commonly anthropomorphised, even in period, as cunning little blighters always after people's food, they also have a reputation for rapid multiplication.
First rabbit: There are a pack of wolves coming. Second rabbit: Quick -- down this hole -- give it ten minutes and we can come out and surround them!.
Commonly alluded to as "bunnies" or "coneys" (but, apparently, not as "cunnies") they are also supposed to be part of the inspiration behind the hobbit of recent legends.