From Wikipedia, the free encyclopedia - View original article
|Male (buck or stag)|
38, see text
|White-tailed Deer range map|
|Male (buck or stag)|
38, see text
|White-tailed Deer range map|
The white-tailed deer (Odocoileus virginianus), also known as the Virginia deer or simply 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. It has also been introduced to New Zealand 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 Dakota and Wyoming to southeastern 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 Prince George, 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.
Until recently,[when?] some taxonomists have attempted to separate white-tailed deer into a host of subspecies, based largely in morphological differences. Genetic studies,[clarification needed] however, suggest that there are fewer subspecies within the animal's range, as compared to the 30 to 40 subspecies that some scientists described in the last century. The Florida Key deer, O. virginianus clavium, and the Columbian white-tailed deer, O. virginianus leucurus, are both listed as endangered under the U.S. Endangered Species Act. In the United States, the Virginia white-tail, O. virginianus virginianus, is among the most widespread subspecies. The white-tailed deer species has tremendous genetic variation and is adaptable to several environments. Several local deer populations, especially in the southern states, are descended from white-tailed deer transplanted from various localities east of the Continental Divide. Some of these deer may have been from as far north as the Great Lakes region to as far west as Texas, yet are also quite at home in the Appalachian and Piedmont regions of the south. These deer over time have intermixed with the local indigenous deer (virginianus and/or macrourus) populations.
Central and South America have a complex number of white-tailed deer subspecies that range from Guatemala as far south as Peru. This list of subspecies of deer is more exhaustive than the list of North American subspecies, and the number of subspecies is also questionable. However, the white-tailed deer populations in these areas are difficult to study, due to over-hunting many parts and lack of protection. Some areas no longer carry deer, so it is difficult to assess the genetic difference of these animals.
The 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. The deer will raise its tail when it is alarmed to flag the other deer. There is a population of white-tailed deer in the state of New York that 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 pupil allows for good night time vision and color vision during the day.
The white-tailed deer is highly variable in size, generally following Bergmann's rule that the average size is larger further away from the Equator. North American male deer (also known as a buck or stag) usually weighs 60 to 130 kg (130 to 290 lb) but, in rare cases, bucks in excess of 159 kg (351 lb) have been recorded. Mature bucks over 400 pounds are 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 25.5 kg (56 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.
Males re-grow their antlers every year. About 1 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 "spike". The spikes can be quite long or very short. Length and branching of antlers is 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 frame damage that may be 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 (one and a half years old). The number of points, the length or thickness of the antlers are 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 that deer that have spiked antlers 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. Where antler growth nutritional needs are met (good mineral sources, i.e., calcium) and good genetics combine it can 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 non-typical antler arrangement. Typical antlers are symmetrical and the points grow straight up off the main beam. Non-typical 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 non-typical antler arrangement. The Boone and Crockett or Pope & 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 will often be scored as "typical". A buck's inside spread can be anywhere from 3–25 in (8–64 cm). Bucks shed their antlers when all females have been bred, from late December to February.
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 (borealis), Dakota white-tailed deer (dacotensis), and Northwest white-tailed deer (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, there is a noticeable difference in size between male and female deer of the savannas. The Texas white-tailed deer (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. There are also populations of Arizona (couesi) and Carmen Mountains (carminis) white-tailed deer that 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 (apurensis and gymnotis) have antler dimensions that are 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 black-tailed deer and mule deer. White-tail incursions in the Trans-Pecos region of Texas has 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 nineteenth century, white-tailed deer have been introduced to Europe. A population of white-tailed deer 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 fauna. The current population of some 30,000 deer originate from four animals provided by Finnish Americans from Minnesota.
Whitetail deer eat large varieties of food, commonly eating legumes and foraging on other plants, including shoots, leaves, cacti, and grasses. They also eat acorns, fruit, and corn. Their special stomach allows them to eat some things that humans cannot, such as mushrooms and poison ivy. Their diet varies by season according to availability of food sources. They will also eat hay, grass, white clover, and other food that 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.
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 quickly eat a variety of different food, digesting it at a later time in a safe area of cover. The Whitetail stomach hosts a complex set of bacteria that change as the deer's diet changes through the seasons. If the bacteria necessary for digestion of a particular food (e.g., hay) are absent it will not be digested.
There are several natural predators of white-tailed deer. Wolves, cougars, American alligators, and (in the tropics) jaguars are the more effective natural predators of white-tailed deer. These predators frequently pick out easily caught young or infirm deer (which is believed to incidentally improve the genetic stock of a population) but can and do take healthy adults of any size. Bobcats, lynxes, bears, wolverines, and packs of coyotes usually will prey mainly on deer fawns. Bears may sometimes attack adult deer while lynxes, coyotes, wolverines and bobcats 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. There are records of American Crows attempting to predate white-tailed deer fawns by pecking around their face and eyes, though there are no accounts of successful predation. 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 predate 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 running away. When they blow the sound alerts all of the other deer in the area. As they run, the flash of their white tails warns other deer (especially in mothers with young) of their alarm. Most natural predators of white-tailed deer hunt by surprising them, engaging in a stealthy ambush, although canids like wolves and coyotes may chase and ambush them over a long period, hoping to exhaust the prey. Felid predators typically try to suffocate the deer by biting them on the throat. In cougars and jaguars, they initially knock the deer off-balance with their own powerful forelegs, whereas in small bobcats and lynxes, they attempt to jump onto the deer to give them a killing bite. In the case of canids and wolverines, the predators try to bite at their limbs and flanks, hobbling them, until they can reach vital organs and the deer can be bled out. Bears, who usually target fawns, will often simply knock down the prey and then start eating it while it is still alive. Alligators snatch deer as the ungulates try to drink from or cross around water, grabbing them with their powerful jaws and dragging them into the water to be drowned.
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 white-tails 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 non-human 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 be nearly as common predators of fawns as coyotes. Bobcats, still somewhat widely found, usually only exploit deer as prey when smaller prey is scarce. There have been discussions 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.
In areas where they are heavily hunted by humans, deer run almost immediately away from people and are quite wary even where not heavily hunted. The deer of Virginia can run faster than their predators and have been recorded at speed 75 km/h (47 mph), this ranks them amongst the fastest of all cervids, alongside the Eurasian roe deer. They can also make jumps 2.7 m (8.9 ft) meters 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 and between its legs. 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 that is causing the threat, using its antlers or in the case of a female just the head to fight off the threat.
In 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. 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. When deer consume earlier-succession plants, this 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. It is even possible that high density deer populations 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.
Males compete for the opportunity of breeding females. Sparring among males determines a dominance hierarchy. Bucks will 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. There are many factors as to how intense the "rutting season" will be. Air temperature is one major factor of this intensity. Any time the temperature rises above 40 °F (4 °C), the males will do much less traveling looking for females, or they will be subject to overheating or dehydrating. Another factor for the strength in rutting activity is competition. If there are numerous males in a particular area, then they will compete more for the females. If there are fewer males or more females, then the selection process will not need to be as competitive.
Females enter estrus, colloquially called the rut, in the autumn, normally in late October or early November, triggered mainly by the declining photoperiod. Sexual maturation of females depends on population density as well as availability of food. Young females will often flee from an area heavily populated with males. Females can mature in their first year, although this is unusual and would occur only at very low population levels. Most females mature at 1–2 years of age. Most are not able to reproduce until six months after they mature. Copulation consists of an ejaculatory thrust which takes place during a brief copulatory jump.
Females give birth to 1–3 spotted young, known as fawns, in mid to late spring, generally in May or June. Fawns lose their spots during the first summer and will weigh from 44 to 77 pounds (20 to 35 kg) by the first winter. Male fawns tend to be slightly larger and heavier than females. For the first four weeks, fawns mostly lie still and hide in vegetation while their mothers forage. They are then able to follow their mothers on foraging trips. They are supposedly weaned after 8–10 weeks, but cases have been seen where mothers have continued to allow nursing long after the fawns have lost their spots (for several months, or until the end of fall) as seen by rehabilitators and other studies. Males will leave their mothers after a year and females leave after two.
Bucks are generally sexually mature at 1.5 years old and will begin to breed even in populations stacked with older bucks.
White-tailed deer communicate in many different ways using sounds, scent, body language, and marking. In addition to the aforementioned blowing in the presence of danger, all white-tailed deer are capable of producing audible noises unique to each animal. Fawns release a high-pitched squeal, known as a bleat, to call out to their mothers. This bleat deepens as the fawn grows until it becomes the grunt of the mature deer-a guttural sound that will attract the attention of any other deer in the area. A doe will make maternal grunts when searching for her bedded fawns. Bucks for their part also grunt, at a pitch lower than that of the doe; this grunt deepens as the buck matures. In addition to grunting, both does and bucks also snort, a sound that often signals an imminent threat. Mature bucks also produce a grunt-snort-wheeze pattern, unique to each animal, that asserts its dominance, aggression and hostility. Another way white-tailed deer communicate is through the use of their white tail. When spooked, it will raise its tail to warn the other deer in the immediate area.
White-tailed deer possess many glands that allow them to produce scents, some of which are so potent they can be detected by the human nose. Four major glands are the pre-orbital, forehead, tarsal, and metatarsal glands. It was originally thought that secretions from the preorbital glands (in front of the eye) were rubbed on tree branches; recent[when?] research suggests this is not so. It has been found that scent from the forehead or sudoriferous glands (found on the head, between the antlers and eyes) is used to deposit scent on branches that overhang "scrapes" (areas scraped by the deer's front hooves prior to rub-urination). The tarsal glands are found on the upper inside of the hock (middle joint) on each hind leg. Scent is deposited from these glands when deer walk through and rub against vegetation. These scrapes are used by bucks as a sort of "sign-post" by which bucks know which other bucks are in the area, and to let does know that a buck is regularly passing through the area—for breeding purposes. The scent from the metatarsal glands, found on the outside of each hind leg, between the ankle and hooves, may be used as an alarm scent. The scent from the Interdigital glands, which are located in between the hooves of each foot, emit a yellow waxy substance with an offensive odor. Deer can be seen stomping their hooves if they sense danger through sight, sound, or smell, this action leaves an excessive amount of odor for the purpose of warning other deer of possible danger.
Throughout the year deer will rub-urinate, a process during which a deer squats while urinating so that urine will run down the insides of the deer's legs, over the tarsal glands, and onto the hair covering these glands. Bucks rub-urinate more frequently during the breeding season. Secretions from the tarsal gland mix with the urine and bacteria to produce a strong smelling odor. During the breeding season does release hormones and pheromones that tell bucks that a doe is in heat and able to breed. Bucks also rub trees and shrubs with their antlers and head during the breeding season, possibly transferring scent from the forehead glands to the tree, leaving a scent other deer can detect.
Sign-post marking (scrapes and rubs) are a very obvious way that white-tailed deer communicate. Although bucks do most of the marking, does visit these locations often. To make a rub, a buck will use its antlers to strip the bark off of small diameter trees, helping to mark his territory and polish his antlers. To mark areas they regularly pass through bucks will make scrapes. Often occurring in patterns known as scrape lines, scrapes are areas where a buck has used its front hooves to expose bare earth. They often rub-urinate into these scrapes, which are often found under twigs that have been marked with scent from the forehead glands.
By the early 20th century, commercial exploitation and unregulated hunting had severely depressed deer populations in much of their range. For example, by about 1930, the U.S. population was thought to number about 300,000. After an outcry by hunters and other conservation ecologists, commercial exploitation of deer became illegal and conservation programs along with regulated hunting were introduced. The Associated Press reported in 2005 that estimates put the deer population in the United States at around 30 million. Conservation practices have proved so successful that, in parts of their range, the white-tailed deer populations currently far exceed their cultural carrying capacity and the animal may be considered a nuisance. A reduction in natural predators (which normally cull young, sick or infirm specimens) has undoubtedly contributed to locally abundant populations.
At high population densities, farmers can suffer economic damage by deer depredation of cash crops, especially in corn and orchards. It has become nearly impossible to grow some crops in some areas unless very burdensome deer-deterring measures are taken. Deer are excellent fence-jumpers, and their fear of motion and sounds meant to scare them away is soon dulled. Timber harvesting and forest clearance have historically resulted in increased deer population densities, which in turn have slowed the rate of reforestation following logging in some areas. High densities of deer can have severe impacts on native plants and animals in parks and natural areas; however, deer browsing can also promote plant and animal diversity in some areas. Deer can also cause substantial damage to landscape plants in suburban areas, leading to limited hunting or trapping to relocate or sterilize them. In parts of the Eastern US with high deer populations and fragmented woodlands, deer often wander into suburban and urban habitats that are less than ideal for the species. Motor vehicle collisions with deer are a serious problem in many parts of the animal's range, especially at night and during rutting season, causing injuries and fatalities among both deer and humans. Vehicular damage can be substantial in some cases. Deer are also the primary host and vector for the adult black-legged tick, which transmits the Lyme disease bacterium to humans.
In the U.S., the species is the state animal of Arkansas, Illinois, Michigan, Mississippi, Nebraska, New Hampshire, Ohio, Pennsylvania, and South Carolina, the wildlife symbol of Wisconsin, and game animal of Oklahoma. The profile of a white-tailed deer buck caps the coat of arms of Vermont and can be seen in the flag of Vermont and in stained glass at the Vermont State House. It is the national animal of Honduras, and the provincial animal of Canadian Saskatchewan and Finnish Pirkanmaa. Texas is home to the most white-tailed deer of any U.S. state or Canadian province, with an estimated population of over four million. Notably high populations of white-tailed deer occur in the Edwards Plateau of Central Texas. Michigan, Minnesota, Mississippi, Missouri, New Jersey, Illinois, Wisconsin, Maryland, New York, North Dakota, Pennsylvania, and Indiana also boast high deer densities. In 1884, one of the first hunts of white-tailed deer in Europe was conducted in Opočno and Dobříš (Brdy mountains area), in what is now the Czech Republic.
|Wikimedia Commons has media related to White-tailed Deer.|
|Wikispecies has information related to: White-tailed Deer|