Pronghorn: Antilocapridae

Pronghorn are among the fastest land animals, able to reach speeds of 53.7 miles per hour (86.5 kilometers per hour) and maintain that pace for several miles (kilometers) before exhaustion sets in. They run with their mouths open to increase oxygen intake. Pronghorn are also strong swimmers.

Pronghorn are vocal animals, and make snorting and "sneezing" sounds when sensing something unfamiliar in their habitat. Fawns make soft bleating sounds (similar to lambs) that help parents locate hidden offspring. Adult females grunt or click when approaching hidden fawns or when being pursued by bucks. Bucks roar when chasing does or other bucks. During courtship, bucks smack their lips and flick their tongues, both of which create a low sucking sound.

Pronghorn males may fight during the breeding season. (© Stephen J. Krasemann/Photo Researchers, Inc. Reproduced by permission.)

Pronghorn live in herds, sometimes loosely scattered, but always highly organized. When threatened, they'll raise their white rump hairs and snort, alerting other herd members to gather together more closely. They are active during daylight and nighttime, with peak activity occurring just after sunrise and before sunset. They spend most of their time feeding or sleeping, the latter of which they do in short spurts and frequently throughout the day.

Home ranges vary greatly and are dependent on quality of habitat, group size, season, and history of land use. Winter and summer ranges may be as far apart as 100 miles (160 kilometers). Bucks will mark their territory with urine and feces.

Pronghorn are polygynous (puh-LIH-juh-nus; one male has several female mates), and mating occurs between July and early October. Pregnancy lasts eight and a half months; a single fawn is born in the spring if this is the doe's first birth. Successive births usually result in twins, rarely triplets. By day four, fawns are able to outrun humans. Fawns nurse (drink mother's milk) until around four weeks of age, at which time they join their mothers on feeding trips.

Pronghorn are sexually mature at sixteen to seventeen months. Primary predators, animals that hunt them for food, include coyotes, wolves, and bobcats. Lifespan is seven to ten years.