Pronghorns are about three feet (one meter) tall at the shoulders. They are reddish brown, but have white stomachs and wide, white stripes on their throats. Being startled they raise the hair on their rumps to display a white warning patch that can be seen for miles. There are no any close relatives to the pronghorns among all the animals of the world: it is the only living member of the Antilocapridae family.

Both sexes sport impressive, backward-curving horns. The horns split to form forward-pointing prongs that give the species its name. Some animals have horns that are more than a foot (30 cm) long. A fleet-footed pronghorn is one of the fastest animals in North America. It can run at more than 53 miles (86 km) an hour, which helps them to run away from bobcats and coyotes, just leaving them in the dust. Even a several days old pronghorn can already run faster than a human!

More Info: animals.nationalgeographic.com