Pennsylvania Game Commission
The white-tailed deer was so named because the underside of its tail is covered with white hair, and when it runs it often holds its tail erect so that the white undersurface is visible. Whitetails belong to the Cervidae family, which in North America includes the elk, moose, caribou and mule deer. Cervids are split-hoofed mammals with no incisor teeth in the front of the upper jaw. They are classed as ruminant animals, meaning they have a four-chambered stomach and frequently chew a "cud." Adult male whitetails grow and shed a set of antlers each year. On rare occasions, females also grow antlers.
Whitetails are the most widely distributed large animal in North America. They are found throughout most of the continental United States, southern Canada, Mexico, Central America and northern portions of South America as far south as Peru. White-tailed deer are common throughout Pennsylvania. The species is absent from much of the western United States, including Nevada, Utah and California (though its close relatives, the mule deer and black-tailed deer, can be found there).