These ruminant mammals are widely distributed, with representatives in all continents except Australia and Africa. Deer differ from other ruminants in that they have antlers instead of horns. The male deer are called stags, harts, bucks, or bulls, and females are called does, hinds, or cows. Young deer are often referred to as fawns or calves.
It is thought that the New World species evolved about five million years ago in the forests of North America and Siberia.