White-tailed deer

White-tailed deer
Male (buck/stag) |~| Female (doe)
General information
Universe	Real Life
Aliases	Whitetail Virginia deer Buck (male) Stag (male) Doe (female)
Classification	Odocoileus virginianus
Species type	Deer
Homeworld	Earth
Environment	Wooded lowlands
Intelligence	Non-sapient
Biochemistry	Carbon-based
Biological information
Lifespan	20 years
Reproduction	Sexual, viviparous
Average height	53 to 120 cm (21 to 47 in) at shoulder
Average weight	♂: 68 to 136 kg (150 to 300 lb) ♀: 40 to 90 kg (88 to 198 lb)
Average length	95 to 220 cm (37 to 87 in) w/o tail
Locomotion	Quadrupedal
Feeding behavior	Herbivorous
Predators	Humans Coyotes Bobcats Wolves Cougars American alligators Jaguars Canada lynxes Grizzly bears American black bears Wolverines Golden eagles Bald eagles
Lineage information
Related species	Yucatan brown brocket Mule deer
Cultural information
Sociocultral characteristics
Scientific taxonomy
Planet	Earth
Domain	Eukaryota
Kingdom	Animalia
Subkingdom	Bilateria
Infrakingdom	Deuterostomia
Phylum	Chordata
Subphylum	Vertebrata
Infraphylum	Gnathostomata
Superclass	Tetrapoda
Class	Mammalia
Subclass	Theria
Infraclass	Placentalia
Superorder	Laurasiatheria
Order	Artiodactyla
Suborder	Ruminantia
Infraorder	Pecora
Family	Cervidae
Subfamily	Capreolinae
Tribe	Rangiferini
Genus	Odocoileus
Species	O. virginianus
Other information
Status	Least Concern
Creator	God (debated)

The white-tailed deer (Odocoileus virginianus) is a medium-sized deer native to North America.

Description

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. It raises its tail when it is alarmed to warn the predator that it has been detected.

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. An indication of a deer age is the length of the snout and the color of the coat, with older deer tending to have longer snouts and grayer coats. 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.

Whitetails process visual images at a much more rapid rate than humans and are better at detecting motion in low-light conditions.

Size and weight

The white-tailed deer is highly variable in size, generally following both Allen's rule and 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 68 to 136 kg (150 to 300 lb), but mature bucks over 180 kg (400 lb) have been recorded in the northernmost reaches of their native range, namely Minnesota, Ontario, and Manitoba. In 1926, Carl J. Lenander Jr., took a white-tailed buck near Tofte, Minnesota, that weighed 183 kg (403 lb) after it was field-dressed (internal organs and blood 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 37 cm (3.9 to 14.6 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. It is among the largest deer species in North America, and the largest in South America.

Deer have dichromatic (two-color) vision with blue and yellow primaries; humans normally 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 has antlers, although this is usually associated with freemartinism. 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. Healthy deer in some areas that are well-fed can have eight-point branching antlers as yearlings (1.5 years old). Although antler size typically increases with age, antler characteristics (e.g., number of points, length, or thickness of the antlers) are not good indicators of buck age, in general, because antler development is influenced by the local environment. The individual deer's nutritional needs for antler growth is dependent on the diet of the deer, particularly protein intake. 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 is 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 North America. 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 some western regions of North America, 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 2020 population of some 109,000 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 muliti-chambered stomachs allow them to eat some foods humans cannot, such as mushrooms, (even those that are toxic to humans)^{[clarification needed]} 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. A grown deer can eat around 2,000 lb (910 kg) of vegetable matter annually. A foraging area around 20 deer per square mile can start to destroy the forest environment.

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 foods, 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

There are several natural predators of white-tailed deer, with wolves, cougars, American alligators, jaguars (in the American southwest, Mexico, and Central and South America) and humans being the most effective natural predators. Aside from humans, 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, grizzly and American black 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, red and gray foxes, and corvids. Few wild predators can afford to be picky and any will readily consume deer as carrion. Records exist of American crows and common ravens 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 warn 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 essentially extirpated in eastern North America, with a very small number of reintroduced critically endangered red wolves, 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 most of Canada. This almost certainly plays a role 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 in the Eastern U.S., besides an occasional domestic dog. In some areas, American black bears are also significant predators. In north-central 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 Eastern U.S., 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 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.

White-tailed deer can run faster than their predators and have been recorded at speeds of 47 mi (76 km) per hour; this ranks them amongst the fastest of all deer, alongside the Eurasian roe deer. They can also jump 9 ft (2.7 m) high and up to 30 ft (9.1 m) forward. When shot at, 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 choose to attack, charging the person or predator posing the threat, using its antlers or, if none are present, its head to fight off its target.

Forest alteration

In certain parts of eastern North America, 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-tailed 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.

Population and controls

The white-tailed deer population in North America has declined by several million since 2000, but as of 2017 is considered healthy and is approximately equal to the historical pre-colonization white-tailed population on the continent. The species has rebounded considerably after being overhunted nearly to extinction in the late 1800s and very early 1900s. By contrast, the species' closest cousins (blacktail deer and mule deer) have seen their populations cut by more than half in North America after peaking in 1960 and have never regained their pre-colonization numbers. In the 21st century, the loss of natural predators has been more than offset by the ongoing loss of natural habitat to human development, and changes to logging operations.

Several methods have been developed to curb the population of white-tailed deer in suburban areas where they are perceived as overabundant, and these can be separated into lethal and nonlethal strategies. Most common in the U.S is the use of extended hunting as population control, as well as a way to provide meat for humans. In Maryland and many other states, a state agency sets regulations on bag limits and hunting in the area depending on the deer population levels assessed. Hunting seasons may fluctuate in duration, or restrictions may be set to affect how many deer or what type of deer can be hunted in certain regions. For the 2015–2016 white-tailed deer-hunting season, some areas allowed only the hunting of antlerless white-tailed deer. These included young bucks and females, encouraging the culling of does which would otherwise contribute to increasing populations via offspring production.

A more targeted yet more expensive removal strategy than public hunting is a method referred to as sharpshooting. Sharpshooting can be an option when the area inhabited by the deer is unfit for public hunting. This strategy may work in areas close to human populations, since it is done by professional marksmen, and requires a submitted plan of action to the city with details of the time and location of the action, as well as number of deer to be culled. Another controversial method involves trapping the deer in a net or other trap, and then administering a chemical euthanizing agent or extermination by firearm. A main issue in questioning the humaneness of this method is the stress that the deer endure while trapped and awaiting extermination.

Nonlethal methods include contraceptive injections, sterilization, and translocation of deer. While lethal methods have municipal support as being the most effective in the short term, some opponents of this view suggest that extermination has no significant impact on deer populations. Opponents of contraceptive methods point out that fertility control cannot provide meat and proves ineffective over time as populations in open-field systems move about. Concerns are voiced that the contraceptives have not been adequately researched for the effect they could have on humans. Fertility control also does nothing to affect the current population and the effects their grazing may be having on the forest plant make-up.

Translocation has been considered overly costly for the little benefit it provides. Deer experience high stress and are at high risk of dying in the process, putting into question its humaneness. Another concern regarding translocation is the possible spreading of chronic wasting disease to unaffected deer populations and concerns about exposure to human populations.

In addition to the danger of deer-vehicle collisions the National Agricultural Statistics Service (NASS) reported that the estimated loss in field crops, nuts, fruits, and vegetables in 2001 was near $765 million.

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.

Reproduction

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 often flee from an area heavily populated with males. Some does may be as young as six months when they reach sexual maturity, but the average age of maturity is 18 months. Copulation consists of a brief copulatory jump.

Females give birth to one to three spotted young, known as fawns, in mid- to late spring, generally in May or June. Fawns lose their spots during the first summer and weigh from 44 to 77 lb (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 are hidden in vegetation by their mothers, who nurse them four to five times a day. This strategy keeps scent levels low to avoid predators. After about a month, the fawns are then able to follow their mothers on foraging trips. They are usually 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 leave their mothers after a year and females leave after two.

Bucks are generally sexually mature at 1.5 years old and begin to breed even in populations stacked with older bucks.

Communication

White-tailed deer have many forms of communication involving 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 attracts the attention of any other deer in the area. A doe makes maternal grunts when searching for her bedded fawns. Bucks 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.

Marking

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 preorbital, forehead, tarsal, and metatarsal glands. Secretions from the preorbital glands (in front of the eye) were thought to be rubbed on tree branches, but research suggests this is not so.^{[citation needed]} 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 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 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 rub-urinate, a process during which a deer squats while urinating so 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 a doe is in heat and able to breed. Bucks also rub trees and shrubs with their antlers and heads 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) is a very obvious way white-tailed deer communicate. Although bucks do most of the marking, does visit these locations often. To make a rub, a buck uses his antlers to strip the bark off small-diameter trees, helping to mark his territory and polish his antlers. To mark areas they regularly pass through, bucks make scrapes. Often occurring in patterns known as scrape lines, scrapes are areas where a buck has used his 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.