Rabbits, both wild and domestic, positively litter medieval illuminations. They seem to have grabbed the imagination of the artists to a far greater extent than any other animal. Rabbits could be shown almost lifelike, as in this Durer example.
Rabbits - "mad as a March hare" -- were often shown gambolling about the place.
Sometimes they were just silly and took on humanoid personalities.
Then again, rabbits could be brave, stalwart, and heroic.
And finally, rabbits could be just out-and-out drolleries.