Pronghorn

The pronghorn (Antilocapra americana) is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American antelope, prong buck, pronghorn antelope and prairie antelope, because it closely resembles the antelopes of the Old World and fills a similar ecological niche due to parallel evolution. It is the only surviving member of the family Antilocapridae. During the Pleistocene epoch, about 11 other antilocaprid species existed in North America, many with long or spectacularly-twisted horns. Three other genera (Capromeryx, Stockoceros and Tetrameryx) existed when humans entered North America but are now extinct.

Source: Wikipedia