Deer (singular and plural) are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, mule deer such as black-tailed deer, elk, moose, red deer, reindeer (caribou), fallow deer, roe deer and chital. Male deer of all species (except the Chinese water deer) and also female reindeer grow and shed new antlers each year. In this they differ from permanently horned animals such as antelope; these are in the same order as deer and may bear a superficial resemblance. The musk deer of Asia and water chevrotain (or mouse deer) of tropical African and Asian forests are not usually regarded as true deer and form their own families, Moschidae and Tragulidae, respectively. The word 'deer' was originally broad in meaning, but became more specific over time. In Middle English der (Old English dor) meant a wild animal of any kind.
Contributions by 220.127.116.11, Tannin, and UtherSRG.