Deers are the ruminant mammals forming the family Cervidae. They include for example Moose, Red Deer, Reindeer, Roe and Chital. Animals from related families within the order Artiodactyls (even-toed ungulates) are often also considered to be deer – these include muntjac and water deer.
Male deer of all species but the Chinese Water deer and female reindeer grow and shed new antlers each year.
Antlers are the usually large and complex bony attachments on the heads of most deer species, mostly on males; only caribou and reindeer have antlers on the females, and these are normally smaller than those of the males.
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 Tragulida.
Deer are widely distributed, and hunted, with indigenous representatives in all continents except Antarctica and Australia, though Africa has only one native species, the Red Deer, confined to the Atlas Mountains in the northwest of the continent.
Deers live in a variety of places ranging from tundra to the tropical rainforest. While often associated with forests, many deer are ecotone species that live in transitional areas between forests and thickets (for cover) and prairie and savanna (open space).
The majority of large deer species inhabit temperate mixed deciduous forest, mountain mixed coniferous forest, tropical seasonal/dry forest, and savanna habitats around the world. Clearing open areas within forests to some extent may actually benefit deer populations by exposing the understory and allowing the types of grasses, weeds, and herbs to grow that deer like to eat.
Additionally, access to adjacent croplands may also benefit deer. However, adequate forest or brush cover must still be provided for populations to grow and thrive.
Deer weights generally range from 40 to 200 kilograms. They generally have flexible, compact bodies and long, powerful legs suited for rugged woodland terrain. Deer are also excellent jumpers and swimmers.
Deer are ruminants, or cud-chewers, and have a four-chambered stomach. The teeth of deer are adapted to feeding on vegetation, and like other ruminants, they lack upper incisors, instead having a tough pad at the front of their upper jaw.