Antelope, common name applied to a large group of hollow-horned ruminants belonging to the same family as cattle, goats, and sheep. The group comprises about 150 species, which are found in Africa and Asia. No true antelope is native to the Americas.

Antelope range dramatically in size. Unlike deer, which they resemble, antelope have unbranched, hollow horns that are never shed. Some species are the fastest of the quadrupeds, attaining speeds of 97 km/h (60 mph). Antelope are often brilliantly colored. They live in a variety of environments, and some species travel in herds.

Scientific Classification: Antelope belong to the family Bovidae.

Pronghorn:

Pronghorn, mammal, related to the antelope, that is considered the fastest animal in North America. It has a maximum recorded speed of 86.5 km/h (53.8 mph). Both sexes have a pair of erect horns. The animal is reddish-brown with a dark brown mane, white underparts, two white bands on its neck, and a large white patch on its rump. It inhabits open plains and semidesert, where it eats grass, sagebrush, and cactus.

Scientific Classification: The pronghorn belongs to the family Antilocapridae, order Artiodactyla. 
It is classified as Antilocapra americana.

From Microsoft Encarta