White-Tailed Deer

The white-tailed deer (Odocoileus virginianus), also known as the whitetail, is a medium-sized deer native to the United States, Canada, Mexico, Central America, and South America as far south as Peru and Bolivia. It has also been introduced to New Zealand, Cuba, Jamaica, Hispaniola, Puerto Rico, Bahamas, Lesser Antilles, and some countries in Europe, such as Finland, the Czech Republic, and Serbia. In the Americas, it is the most widely distributed wild ungulate.

In North America, the species is widely distributed east of the Rocky Mountains, but elsewhere, it is mostly replaced by the black-tailed or mule deer (Odocoileus hemionus). In western North America, it is found in aspen parklands and deciduous river bottomlands within the central and northern Great Plains, and in mixed deciduous riparian corridors, river valley bottomlands, and lower foothills of the northern Rocky Mountain regions from South Dakotaand Wyoming to northeastern British Columbia, including the Montana Valley and Foothill grasslands.

The conversion of land adjacent to the northern Rockies into agriculture use and partial clear-cutting of coniferous trees (resulting in widespread deciduous vegetation) has been favorable to the white-tailed deer and has pushed its distribution to as far north as Fort St. John, British Columbia. Populations of deer around the Great Lakes have also expanded their range northwards, due to conversion of land to agricultural uses favoring more deciduous vegetation, and local caribou and moose populations. The westernmost population of the species, known as the Columbian white-tailed deer, once was widespread in the mixed forests along the Willamette and Cowlitz River valleys of western Oregon and southwestern Washington, but today its numbers have been considerably reduced, and it is classified as near-threatened.

Description[]

he deer's coat is a reddish-brown in the spring and summer and turns to a grey-brown throughout the fall and winter. The deer can be recognized by the characteristic white underside to its tail. It will raise its tail when it is alarmed to flag the other deer. A population of white-tailed deer in New York is entirely white (except for areas like their noses and toes)—not albino—in color. The former Seneca Army Depot in Romulus, New York, has the largest known concentration of white deer. Strong conservation efforts have allowed white deer to thrive within the confines of the depot. White-tailed deer's horizontally slit pupils allow for good night vision and color vision during the day.

Size and Weight[]

The white-tailed deer is highly variable in size, generally following Bergmann's rule that the average size is larger farther away from the Equator. North American male deer (also known as a buck) usually weigh 45 kilograms (100 lb), but in rare cases, bucks in excess of 125 kilograms (275 lb) have been recorded. Mature bucks over 180 kilograms (400 lb) have been recorded in the northernmost reaches of their native range, specifically, Minnesota and Ontario. In 1926, Carl J. Lenander, Jr. took a white-tailed buck near Tofte, MN, that weighed 183 kg (403 lb) after it was field-dressed (internal organs removed) and was estimated at 232 kg (511 lb) when alive. The female (doe) in North America usually weighs from 40 to 90 kg (88 to 198 lb). White-tailed deer from the tropics and the Florida Keys are markedly smaller-bodied than temperate populations, averaging 35 to 50 kg (77 to 110 lb), with an occasional adult female as small as 25 kg (55 lb). White-tailed deer from the Andes are larger than other tropical deer of this species and have thick, slightly woolly looking fur. Length ranges from 95 to 220 cm (37 to 87 in), including a tail of 10 to 36.5 cm (3.9 to 14.4 in), and the shoulder height is 53 to 120 cm (21 to 47 in). Including all races, the average summer weight of adult males is 68 kg (150 lb) and is 45.3 kg (100 lb) in adult females.

Deer have dichromatic (two-color) vision with blue and yellow primaries; humans have trichromatic vision. Thus, deer poorly distinguish the oranges and reds that stand out so well to humans. This makes it very convenient to use deer-hunter orange as a safety color on caps and clothing to avoid accidental shootings during hunting seasons.

Antlers[]

Males regrow their antlers every year. About one in 10,000 females also have antlers, although this is usually associated with hermaphroditism. Bucks without branching antlers are often termed "spikehorn", "spiked bucks", "spike bucks", or simply "spikes/spikers". The spikes can be quite long or very short. Length and branching of antlers are determined by nutrition, age, and genetics. Rack growth tends to be very important from late spring until about a month before velvet sheds. During this time, damage done to the racks tends to be permanent. Healthy deer in some areas that are well-fed can have eight-point branching antlers as yearlings (1.5 years old). The number of points, the length, or thickness of the antlers is a general indication of age, but cannot be relied upon for positive aging. A better indication of age is the length of the snout and the color of the coat, with older deer tending to have longer snouts and grayer coats. Some say spiked-antler deer should be culled from the population to produce larger branching antler genetics (antler size does not indicate overall health), and some bucks' antlers never will be wall trophies. Good antler-growth nutritional needs (calcium) and good genetics combine to produce wall trophies in some of their range. Spiked bucks are different from "button bucks" or "nubbin' bucks", that are male fawns and are generally about six to nine months of age during their first winter. They have skin-covered nobs on their heads. They can have bony protrusions up to a half inch in length, but that is very rare, and they are not the same as spikes.

Antlers begin to grow in late spring, covered with a highly vascularised tissue known as velvet. Bucks either have a typical or atypical antler arrangement. Typical antlers are symmetrical and the points grow straight up off the main beam. Atypical antlers are asymmetrical and the points may project at any angle from the main beam. These descriptions are not the only limitations for typical and atypical antler arrangement. The Boone and Crockett or Pope and Young scoring systems also define relative degrees of typicality and atypicality by procedures to measure what proportion of the antlers are asymmetrical. Therefore, bucks with only slight asymmetry are scored as "typical". A buck's inside spread can be from 3 to 25 in (8–64 cm). Bucks shed their antlers when all females have been bred, from late December to February.

Ecology[]

White-tailed deer are generalists and can adapt to a wide variety of habitats. The largest deer occur in the temperate regions of Canada and United States. The northern white-tailed deer (O. v. borealis), Dakota white-tailed deer (O. v. dacotensis), and northwest white-tailed deer (O. v. ochrourus) are some of the largest animals, with large antlers. The smallest deer occur in the Florida Keys and in partially wooded lowlands in the neotropics.

Although most often thought of as forest animals depending on relatively small openings and edges, white-tailed deer can equally adapt themselves to life in more open prairie, savanna woodlands, and sage communities as in the Southwestern United States and northern Mexico. These savanna-adapted deer have relatively large antlers in proportion to their body size and large tails. Also, a noticeable difference exists in size between male and female deer of the savannas. The Texas white-tailed deer (O. v. texanus), of the prairies and oak savannas of Texas and parts of Mexico, are the largest savanna-adapted deer in the Southwest, with impressive antlers that might rival deer found in Canada and the northern United States. Populations of Arizona (O. v. couesi) and Carmen Mountains (O. v. carminis) white-tailed deer inhabit montane mixed oak and pine woodland communities. The Arizona and Carmen Mountains deer are smaller, but may also have impressive antlers, considering their size. The white-tailed deer of the Llanos region of Colombia and Venezuela (O. v. apurensis and O. v. gymnotis) have antler dimensions similar to the Arizona white-tailed deer.

In western regions of the United States and Canada, the white-tailed deer range overlaps with those of the mule deer. White-tail incursions in the Trans-Pecos region of Texas have resulted in some hybrids. In the extreme north of the range, their habitat is also used by moose in some areas. White-tailed deer may occur in areas that are also exploited by elk (wapiti) such as in mixed deciduous river valley bottomlands and formerly in the mixed deciduous forest of eastern United States. In places such as Glacier National Park in Montana and several national parks in the Columbian Mountains (Mount Revelstoke National Park) and Canadian Rocky Mountains, as well as in the Yukon Territory ( Yoho National Park and Kootenay National Park), white-tailed deer are shy and more reclusive than the coexisting mule deer, elk, and moose.

Central American white-tailed deer prefer tropical and subtropical dry broadleaf forests, seasonal mixed deciduous forests, savanna, and adjacent wetland habitats over dense tropical and subtropical moist broadleaf forests. South American subspecies of white-tailed deer live in two types of environments. The first type, similar to the Central American deer, consists of savannas, dry deciduous forests, and riparian corridors that cover much of Venezuela and eastern Colombia. The other type is the higher elevation mountain grassland/mixed forest ecozones in the Andes Mountains, from Venezuela to Peru. The Andean white-tailed deer seem to retain gray coats due to the colder weather at high altitudes, whereas the lowland savanna forms retain the reddish brown coats. South American white-tailed deer, like those in Central America, also generally avoid dense moist broadleaf forests.

Since the second half of the 19th century, white-tailed deer have been introduced to Europe. A population in the Brdy area remains stable today. In 1935, white-tailed deer were introduced to Finland. The introduction was successful, and the deer have recently begun spreading through northern Scandinavia and southern Karelia, competing with, and sometimes displacing, native species. The current population of some 30,000 deer originated from four animals provided by Finnish Americans from Minnesota.

Diet[]

White-tailed deer eat large amounts of food, commonly eating legumes and foraging on other plants, including shoots, leaves, cacti (in deserts), prairie forbs, and grasses. They also eat acorns, fruit, and corn. Their special stomachs allow them to eat some things humans cannot, such as mushrooms and poison ivy. Their diets vary by season according to availability of food sources. They also eat hay, grass, white clover, and other foods they can find in a farm yard. Though almost entirely herbivorous, white-tailed deer have been known to opportunistically feed on nesting songbirds, field mice, and birds trapped in mist nets, if the need arises.

The white-tailed deer is a ruminant, which means it has a four-chambered stomach. Each chamber has a different and specific function that allows the deer to eat a variety of different food, digesting it at a later time in a safe area of cover. The stomach hosts a complex set of microbes that change as the deer's diet changes through the seasons. If the microbes necessary for digestion of a particular food (e.g., hay) are absent, it will not be digested.

Predators[]

Several natural predators of white-tailed deer occur. Wolves, cougars, American alligators, jaguars (in the tropics), and humans are the most effective natural predators of white-tailed deer. These predators frequently pick out easily caught young or infirm deer (which is believed to improve the genetic stock of a population), but can and do take healthy adults of any size. Bobcats, Canada lynx, bears, wolverines, and packs of coyotes usually prey mainly on fawns. Bears may sometimes attack adult deer, while lynxes, coyotes, and wolverines are most likely to take adult deer when the ungulates are weakened by harsh winter weather. Many scavengers rely on deer as carrion, including New World vultures, raptors, foxes, and corvids. Few wild predators can afford to be picky and any will readily consume deer as carrion. Records exist of American crows attempting to prey on white-tailed deer fawns by pecking around their face and eyes, though no accounts of success are given. Occasionally, both golden and bald eagles may capture deer fawns with their talons. In one case, a golden eagle was filmed in Illinois unsuccessfully trying to prey on a large mature white-tailed deer.

White-tailed deer typically respond to the presence of potential predators by breathing very heavily (also called blowing) and fleeing. When they blow, the sound alerts other deer in the area. As they run, the flash of their white tails warns other deer. This especially serves to warns fawns when their mother is alarmed. Most natural predators of white-tailed deer hunt by ambush, although canids may engage in an extended chase, hoping to exhaust the prey. Felids typically try to suffocate the deer by biting the throat. Cougars and jaguars will initially knock the deer off balance with their powerful forelegs, whereas the smaller bobcats and lynxes will jump astride the deer to deliver a killing bite. In the case of canids and wolverines, the predators bite at the limbs and flanks, hobbling the deer, until they can reach vital organs and kill it through loss of blood. Bears, which usually target fawns, often simply knock down the prey and then start eating it while it is still alive. Alligators snatch deer as they try to drink from or cross bodies of water, grabbing them with their powerful jaws and dragging them into the water to drown.

Most primary natural predators of white-tailed deer have been basically extirpated in eastern North America, with a very small number of reintroduced red wolves, which are nearly extinct, around North Carolina and a small remnant population of Florida panthers, a subspecies of the cougar. Gray wolves, the leading cause of deer mortality where they overlap, co-occur with whitetails in northern Minnesota, Wisconsin, Michigan, and parts of Canada. This almost certainly plays a factor in the overpopulation issues with this species. Coyotes, widespread and with a rapidly expanding population, are often the only major nonhuman predator of the species, besides an occasional domestic dog. In some areas, American black bears are also significant predators. In northcentral Pennsylvania, black bears were found to be nearly as common predators of fawns as coyotes. Bobcats, still fairly widespread, usually only exploit deer as prey when smaller prey is scarce. Discussions have occurred regarding the possible reintroduction of gray wolves and cougars to sections of the eastern United States, largely because of the apparent controlling effect they have through deer predation on local ecosystems, as has been illustrated in the reintroduction of wolves to Yellowstone National Park and their controlling effect on previously overpopulated elk. However, due to the heavy urban development in much of the East and fear for livestock and human lives, such ideas have ultimately been rejected by local communities and/or by government services and have not been carried through. Replacing most natural predators is the automobile with Oakland County, Michigan having the record number on annual average of collisions between white tailed deer and vehicles.

In areas where they are heavily hunted by humans, deer run almost immediately from people and are quite wary even where not heavily hunted. In most areas where hunting may occur deer seem to develop an acute sense of time and a fondness for metro parks and golf courses. This rather odd occurrence is best noted in Michigan, where in the lower peninsula around late August early September they begin to move out of less developed areas in favor of living near human settlements.

The deer of Virginia can run faster than their predators and have been recorded at speeds of 75 km (47 mi) per hour;^[40] this ranks them amongst the fastest of all cervids, alongside the Eurasian roe deer. They can also jump 2.7 m (8.9 ft) high and up to 10 m (33 ft) in length. When shot at, the white-tailed deer will run at high speeds with its tail down. If frightened, the deer will hop in a zig-zag with its tail straight up. If the deer feels extremely threatened, however, it may charge the person or predator causing the threat, using its antlers or, if none are present, its head to fight off the threat.

Forest Alteration[]

In certain parts of the eastern United States, high deer densities have caused large reductions in plant biomass, including the density and heights of certain forest wildflowers, tree seedlings, and shrubs. Although they can be seen as a nuisance species, white tail deer also play an important role in biodiversity. At the same time, increases in browse-tolerant grasses and sedges and unpalatable ferns have often accompanied intensive deer herbivory. Changes to the structure of forest understories have, in turn, altered the composition and abundance of forest bird communities in some areas. Deer activity has also been shown to increase herbaceous plant diversity, particularly in disturbed areas, by reducing competitively dominant plants; and to increase the growth rates of important canopy trees, perhaps by increased nutrient inputs into the soil. In northeastern hardwood forests, high-density deer populations affect plant succession, particularly following clear-cuts and patch cuts. In succession without deer, annual herbs and woody plants are followed by commercially valuable, shade-tolerant oak and maple. The shade-tolerant trees prevent the invasion of less commercial cherry and American beech, which are stronger nutrient competitors, but not as shade tolerant. Although deer eat shade-tolerant plants and acorns, this is not the only way deer can shift the balance in favor of nutrient competitors. Deer consuming earlier-succession plants allows in enough light for nutrient competitors to invade. Since slow-growing oaks need several decades to develop root systems sufficient to compete with faster-growing species, removal of the canopy prior to that point amplifies the effect of deer on succession. High-density deer populations possibly could browse eastern hemlock seedlings out of existence in northern hardwood forests; however, this scenario seems unlikely, given that deer browsing is not considered the critical factor preventing hemlock re-establishment at large scales. Ecologists have also expressed concern over the facilitative effect high deer populations have on invasions of exotic plant species. In a study of eastern hemlock forests, browsing by white-tailed deer caused populations of three exotic plants to rise faster than they do in the areas which are absent of deer. Seedlings of the three invading species rose exponentially with deer density, while the most common native species fell exponentially with deer density, because deer were preferentially eating the native species. The effects of deer on the invasive and native plants were magnified in cases of canopy disturbance.

Behavior[]

Males compete for the opportunity of breeding females. Sparring among males determines a dominance hierarchy. Bucks attempt to copulate with as many females as possible, losing physical condition, since they rarely eat or rest during the rut. The general geographical trend is for the rut to be shorter in duration at increased latitude. Many factors determine how intense the "rutting season" will be; air temperature is a major one. Any time the temperature rises above 40 °F (4 °C), the males do much less traveling looking for females, else they will be subject to overheating or dehydrating. Another factor for the strength in rutting activity is competition. If numerous males are in a particular area, then they compete more for the females. If fewer males or more females are present, then the selection process will not need to be as competitive.