- Author: Robert J Keiffer
The Black-tailed Jackrabbit (Lepus californicus) is the third largest North American hare. Being a true hare species, they have large ears, long powerfull hind feet, and their young (called leverets) are borne fully furred with eyes open and are mobile within minutes of birth. This species may actually have the largest ear-surface to body-size ratio of any animal on earth. These huge ears not only allow for acute hearing (helps to be aware of predators) but also allows the animal to regulate its body temperature by increasing or decreasing the blood flowing through them.
The most common hare of the western United States and Mexico, these rabbits host many ectoparasites including fleas, ticks, lice, and mites. A Western black-legged tick (Ixodes pacificus) collected from a Black-tailed jackrabbit at the UC Hopland Research & Extension Center in 1983, by UC Berkeley entomologist Dr. Robert Lane, carried the first-known Lyme Disease spirochete (Borrelia burgdorferi) west of the Mississippi River.