Pronghorn (Antilocapra americana).—Leonard Lee Rue III
Ruminant (Antilocapra americana) of North American plains and semideserts, the only living member of the family Antilocapridae. The pronghorn stands 30–40 in. (80–100 cm) tall. It is reddish brown with a short, dark-brown mane, white underparts, two white bands on the throat, and a circular white patch on the rump. Both sexes bear erect, two-pronged horns; the longer prong curves backward, the shorter prong forward. Pronghorns live alone or in small bands in summer, and in large herds in winter. The fastest mammal of North America, the pronghorn can run 45 mph (70 kph) and can bound up to 20 ft (6 m). Though tens of millions once roamed the West, they were nearly exterminated by hunters in the early 20th century; conservation efforts have since allowed their populations to increase.