a large North American hare (=animal like a large rabbit) with very long ears. Any of several large, common North American species of hares (e.g., Lepus townsendii, L. californicus). Jackrabbits have very long ears and long hind legs. They are widespread, particularly in the West, but are found most often in prairie and plains environments
JACKRABBIT START ... The sudden acceleration of a motor vehicle from a standing stop. ... The analogy is to a jackrabbit (q.v.) leaping suddenly from cover and bounding quickly away when disturbed by a dog or a hunter.