The white-tailed jackrabbit, or "jack," is the largest member of the rabbit and hare family, weighing from six to ten pounds. The long-legged jackrabbit is best recognized by its unusual style of running. When surprised, it will usually bound off with a gait resembling that of a kangaroo. But when frightened, it will drop low to the ground and accelerate to an amazingly fast speed. It is rarely seen because it is active mainly at night, and turns white in winter.
For more information, see http://www.dnr.state.mn.us/mammals/whitetailedjackrabbit.html