|A white-tailed doe and two fawns|
Deer are a large family of over thirty species of even-toed ungulates, occurring naturally throughout much of the world, and introduced to parts of Australasia. Only in Africa, where deer, apart from the Atlas Deer, are replaced by antelopes, are they largely absent.
Seasonal movements involving migrations from higher elevations (summer ranges) to lower winter ranges are associated, in part, with decreasing temperatures, severe snowstorms, and snow depths that reduce mobility and food supply. Deep snows ultimately limit usable range to a fraction of the total. Deer in the arid southwest may migrate in response to rainfall patterns.
Deer are highly adaptable, equipped with slender but muscular legs, and cloven hooves that allow them to easily leap, climb hillsides and keep their balance. They can get up on their hind legs to reach branches. They can jump fences as high as eight feet, or can squeeze under them. They can, if necessary, crawl.
Deer are not often vocal, although young fawns bleat on occasion. Injured deer utter a startlingly loud BLATT or bawl.
Food of the deer is quite varied. Deer are a crepuscular species; they emerge to feed at dusk and dawn.
They are a browsing species, capable of eating a huge variety of grasses and leaves and other vegetative matter, which they digest in their four-chambered ruminant stomach. Deer like to eat acorns, berry brambles, yew, sweet ground covers and scores of other plants; if necessary they will also eat poison ivy, twigs or tree bark.
In spring and summer they feed on green leaves, herbs, weeds and grasses more than on browse species. The reverse is true in fall and winter. Deer are browsers and eat a great variety of vegetable matter, including fresh green leaves, twigs, lower branches of trees, and various grasses. They are particularly fond of blackberry and raspberry vines, grapes, eggplant, mistletoe, mushrooms, and ferns. They eat so carefully they can even consume the fruit of cactus.
The mating season for deer reaches its peak in November and December, as antlered stags round up females and fight for their possession. Antlers are shed from mid-January to about mid-April. Most mature bucks in good condition have lost theirs by the end of February; immature bucks generally lose them a little later. Males and females mix freely while traveling together in groups during winter months, often down to the desert floor. Dominance is largely a function of size, with the largest males, which possess the largest antlers, performing most of the copulations. Deer breed in late November and early December. A buck will find a suitable doe and they will often play chase games at breakneck speeds before mating. They will remain together for several days. When antlers start growing again in the spring, the group breaks up. The females go off by themselves and eventually give birth and nurse their young; the males wander in friendly twosomes or small bands throughout the summer months as antlers grow.
From April through June, after about a 400-day gestation period, the fawns are born. Does typically give birth to twins, but well-fed suburban deer have been known to produce triplets. Fawns are born in late May or early June. A doe will usually produce a single fawn the first year she gives birth and then produce twins in following years. The fawn, colored reddish with white spots, weighs about 60 pounds at birth. It must nurse within the first hour and stand within the first 12 hours. During early weeks of life, the fawn sees its mother only at mealtimes for feeding. Spots begin to fade by the end of the first month. They have white camouflage spots and are further protected by having little or no scent. Fawns usually stay with the doe for the first full year.
Many species of deer are hunted for meat and sport.
Before 1600, deer were plentiful in North America. Native Americans hunted them, as did cougars and other large predators. Colonists, when they came, did the same and traded pelts to Europe. Later, market hunting—killing deer to transport their meat to American cities—severely reduced their numbers. A hundred years ago there were less than half a million white-tail and mule deer; deer were almost extinct in many parts of the country.
Today there may be as many as 29 million. The maximum stable population is about 20 deer per square mile, but much higher densities appear in suburban areas, where they enjoy upscale meals from flower beds and landscaping. Deer are an "edge species." They can handle different environments, but they prefer boundary regions between woods and grasslands. The deep center of a mature forest is not ideal for deer. They do better at the edge of a forest, where sunlight and ground vegetation are abundant, and where they can venture to browse in the open but retreat easily into cover.
In 2000—the last time the Centers for Disease Control and Prevention did a count—there were about 247,000 crashes involving animals, mostly deer, on American roadways. Annually, there are about 200 human fatalities involving a vehicle and an animal. In the fall comes "the rut"—bucks chasing does, sometimes for miles—creates a surge in car collisions. In the summer, when fawns begin to follow their mothers, there will be another spike in accidents.
Deer do not themselves contract Lyme disease, but they carry ticks that can spread the illness.