Antilocapra americana

The pronghorn (UK: /ˈprɒŋhɔːrn/, US: /ˈprɔːŋ-/) (Antilocapra americana) is a species of artiodactyl mammal indigenous to interior western and central North America. Though not an antelope, it is often known colloquially in North America as the American antelope, prong buck, pronghorn antelope, prairie antelope, or simply antelope because it closely resembles the true 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 12 antilocaprid species existed in North America. Three other genera (Capromeryx, Stockoceros and Tetrameryx) existed when humans entered North America but are now extinct. As a member of the superfamily Giraffoidea, the pronghorn's closest living relatives are the giraffes and okapi. The Giraffoidea are in turn members of the infraorder Pecora, making pronghorns more distant relatives of the Cervidae (deer) and Bovidae (cattle, goats, sheep, antelopes, and gazelles), among others. The scientific name of the pronghorn is Antilocapra americana. The pronghorn is the sole extant member of the family Antilocapridae. This species was first described by American ornithologist George Ord in 1815. The pronghorn were first seen and described by Spanish explorers in the 16th century, but were not formally recorded or scrutinised till the 1804–1806 expedition by Captain Meriwether Lewis and Second Lieutenant William Clark. The expedition, which aimed to unravel water routes in the continent for commercial purposes, led to the discovery or formal recognition of a variety of flora and fauna of North America. Following the discovery of a few subspecies of the sharp-tailed grouse, Lewis and Clark came across the pronghorn near the mouth of the Niobrara River, in present-day Nebraska. Clark was the first to kill a pronghorn, and described his experience as follows: Lewis and Clark made several other observations on the behavior of the pronghorn and how the local tribes hunted them. They described the animal, which they referred to as the 'Antelope' or the 'Goat', as follows: Pronghorns have distinct white fur on their rumps, sides, breasts, bellies, and across their throats. Adult males are 1.3–1.5 m (4 ft 3 in–4 ft 11 in) long from nose to tail, stand 81–104 cm (32–41 in) high at the shoulder, and weigh 40–65 kg (88–143 lb). The females are the same height as males, but weigh 34–48 kg (75–106 lb). The feet have two hooves, with no dewclaws. Their body temperature is 38 °C (100 °F). The orbits (eye sockets) are prominent and set high on the skull, with never an anteorbital pit. Their teeth are hypsodont, and their dental formula is 0.0.3.33.1.3.3. Each 'horn' of the pronghorn is composed of a slender, laterally flattened blade of bone that grows from the frontal bones of the skull, forming a permanent core. As in the Giraffidae, skin covers the bony cores, but in the pronghorn, it develops into a keratinous sheath which is shed and regrown annually. Unlike the horns of the family Bovidae, the horn sheaths of the pronghorn are branched, each sheath having a forward-pointing tine (hence the name pronghorn). Males have a horn sheath about 12.5–43 cm (4.9–16.9 in) (average 25 cm (9.8 in)) long with a prong. Females have smaller horns that range from 2.5–15.2 cm (1–6 in) (average 12 centimetres (4.7 in)) and sometimes barely visible; they are straight and very rarely pronged. Males are further differentiated from females in having a small patch of black hair at the angle of the mandible. Pronghorns have a distinct, musky odor. Males mark territory with a preorbital scent gland which is on the sides of the head. They also have very large eyes with a 320° field of vision. Unlike deer, pronghorns possess a gallbladder.