The term 'Pronghorn' refers to a species of ANTELOPE native to North America. It is also known as the American ANTELOPE, and is the only surviving member of the family Antilocapridae. It is closely related to DEER, but is not a true DEER species. Pronghorns are the fastest land mammal in the Western Hemisphere, capable of running at speeds up to 55 mph. They have distinctive horns that are shed annually, and are found in open grasslands and shrublands.