White-tailed deer, the smallest members of the North American deer family, are found from southern Canada to South America. There are about 100 types of deer, including the whitetail deer, reindeer, elk, moose, mule deer, blacktail deer and caribou.
Male deer are called bucks, bulls, stags or harts. Female deer are called does, cows or hinds.
In the heat of summer they typically inhabit fields and meadows using clumps of broad-leaved and coniferous forests for shade. During the winter they generally keep to forests, preferring coniferous stands that provide shelter from the harsh elements. Adult white-tails have reddish-brown coats in summer which fade to a duller grayish-brown in winter.
Female deer, called does, give birth to one to three young at a time, usually in May or June and after a gestation period of seven months. Young deer, called fawns, wear a reddish-brown coat with white spots that helps them blend in with the forest.
Deer can adapt well to just about any habitat. They prefer to live in "edge" habitats. Edges are human-made or natural habitat breaks, for instance from woods to croplands. They will use the woodlands for cover and shelter and the open land to graze in. In northern latitudes, deer may live in different areas in the summer and winter months. These areas can be as far as 30 miles apart.
Deer have a great sense of hearing. They have a lot of muscles attached to their ears which allow them to turn their ears in any direction, without moving their heads. They can hear higher frequencies of sound than humans.
Deer have their eyes on the sides of their head, giving them a 310 degree view. This wide view does make it hard for deer to focus on a single point. Deer have a good night vision, which is useful in the early morning and near dusk.
Deer have small teeth in the front of the bottom jaw, which they use for tearing and breaking apart food. They have no teeth in the front of the top jaw. Instead they have a hard palate, which is used in much the same way as teeth. In the back of the mouth deer have molars, canines and incisors, which are used for chewing.
White-tailed deer are herbivores, leisurely grazing on most available plant foods. Their stomachs allow them to digest a varied diet, including leaves, twigs, fruits and nuts, grass, corn, alfalfa, and even lichens and other fungi. Occasionally venturing out in the daylight hours, white-tailed deer are primarily nocturnal or crepuscular, browsing mainly at dawn and dusk.
In the wild, white-tails, particularly the young, are preyed upon by bobcats, mountain lions, and coyotes. They use speed and agility to outrun predators, sprinting up to 30 miles (48 kilometers) per hour and leaping as high as 10 feet (3 meters) and as far as 30 feet (9 meters) in a single bound.
Deer are ungulate, which means that they have two-toed hoofs. They have long legs with powerful muscles and are able to run 40 miles per hour and jump 10 feet high. They are also fast swimmers.
The life expectancy of deer is 20 years.
Deer are born with four baby teeth and develop baby incisors and premolars in their first months. Their adult teeth come in and replace the baby teeth when they are about 18 months old. You can guess the age of deer by looking at the type of teeth they have and by how worn these teeth are. Each year, molars loose about one millimeter of height.