Overview
The Antelope Jackrabbit (Lepus alleni) is an extraordinary, long-eared desert hare native to the scorching heart of the Sonoran Desert. Famous for its colossal, translucent ears that measure up to seven inches long and its unique ability to flash brilliant white flank patches like an African antelope while sprinting at 40 miles per hour across cactus flats, it is an iconic master of desert thermoregulation.
Biology and Physical Characteristics
Lepus alleni has a large, rangy build with exceptionally long, powerful hind legs and colossal, papery ears that are nearly devoid of hair. Its dorsal coat is pale yellowish-brown, but its flanks and rump possess brilliant snowy-white fur that it can roll upward over its back using specialized subcutaneous muscles. Its ears are heavily vascularized with extensive networks of blood vessels that radiate excess metabolic heat into desert breezes.
Behavior and Ecology
A nocturnal and crepuscular forager, the Antelope Jackrabbit spends blistering daytime hours resting in a shallow scraped depression (form) under the shade of a mesquite tree, keeping its giant ears angled toward cool drafts. When alarmed by a coyote or bobcat, it erupts into explosive zig-zag leaps, flashing its gleaming white rump and flanks to dazzle and confuse the predator while racing across rugged desert terrain.
Conservation and Human Impact
Classified as Least Concern by the IUCN, the Antelope Jackrabbit remains common across protected federal lands in southern Arizona, including Saguaro National Park. However, suburban expansion around Tucson, cattle overgrazing that degrades native perennial desert grasses, and highway mortality present ongoing local challenges.
Interesting Factoid
The Antelope Jackrabbit’s colossal 7-inch ears function like biological car radiators: when the desert heats up, it pumps hot blood through thousands of tiny vessels in its ears, dissipating body heat without losing a single drop of precious sweat.