Pronghorn are medium-sized hoofed mammals native to the plains of North America. Their common name refers to their distinctive antlers. Although they are sometimes called pronghorn antelope, the species is not related to true antelope. These animals are found, where conditions permit, from the southern plains of Canada south through the Rockies and Great Plains of the US to northern Mexico. They are among the fastest animals in the world.
Although pronghorn were formerly classified as a kind of antelope, scientists now consider them a unique species not closely related to any other. They are classified as Antilocapra americana, the only member of the Antilocapridae family. There are five recognized sub-species of pronghorn, two of which, the Sonoran and peninsular pronghorn, are considered endangered.
Pronghorn have relatively long legs and ears, with a strong resemblance to deer and many kinds of African antelope. Adults stand from 30 to 40 inches (about 75 to 100 cm) at the shoulder and weigh about 75 to 150 pounds (about 34 to 68 kg.) Males are larger than females.
Their fur is reddish to dark brown with white stripes on the neck and patches of white on the underside and face. Males have a black patch on the side of the face. A large patch of white under the tail has long hairs that fan out when the tail is raised, used as a visual alarm to alert other pronghorn to potential danger.
The antlers or horns of this species are most accurately called horn sheathes. They are unique to the species, having characteristics of both true horns and true antlers. Both sexes have horn sheathes, but only the males have the back-sweeping, branched type which give the species its name. The longest horn sheathes are about 15 inches (about 40 cm) long.
Although they live on grasslands or prairie, the animals eat mostly sagebrush and other shrubs. They also eat a variety of leafy low growing plants. Pronghorn will occasionally eat grass and have been observed eating cacti. If their food supply is moist enough they do not need to drink water on a regular basis.
Breeding season is in the fall, with mid-summer births the following year. After their first breeding season females typically give birth to two fawns. The babies can stand within hours of birth and can run when only days old. Although they begin to eat grass at about three weeks old the fawns usually remain with their mother for between 12 and 18 months.