White-tailed deer

White-tailed Deer
Male (buck or stag)
Female (doe), Ontario
Conservation status

Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Cervidae
Subfamily: Capreolinae
Genus: Odocoileus
Species: O. virginianus
Binomial name
Odocoileus virginianus
Zimmermann, 1780
Subspecies

38, see text
Male white-tailed deer

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 (all but five of the states), Canada, Mexico, Central America, and in South America as far south as Peru. It has also been introduced to New Zealand and some countries in Europe, such as Finland and the Czech Republic.

The species is most common east of the Rocky Mountains, and is absent from much of the western United States, including Nevada, Utah, California, Hawaii, and Alaska (though its close relatives, the mule deer and black-tailed deer Odocoileus hemionus, can be found there). It does, however, survive 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.

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. The white-tailed deer is well-suited for its environment. Fossil records indicate that its basic structure has not changed in four million years.

Contents

Taxonomy

Fawn waving its white tail

Until recently, some taxonomists have attempted to separate white-tailed deer into a host of subspecies, based largely in morphological differences. Genetic studies, 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. The dominant subspecies across the deer's range is the Virginia white-tail, O. virginianus virginianus which is also the type species for the Odocoileus genus. 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 southern Mexico 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. 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.

Subspecies

Some subspecies names, ordered alphabetically except first entry: [2][3]

O. v. truei, female, Costa Rica

Description

White-tailed deer during late winter

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, which it shows as a signal of alarm by raising the tail during escape.

The North American male deer (also known as a buck) usually weighs from 130 to 300 pounds (60 to 130 kg) but, in rare cases, bucks in excess of 375 pounds (159 kg) have been recorded. The female (doe) usually weighs from 90 to 200 pounds (40 to 90 kg). Length ranges from 62 to 87 inches (160 to 220 cm), including the tail, and the shoulder height is 32 to 40 inches (80 to 100 cm).[4] White-tailed deer from the tropics tend to be smaller than in temperate populations, averaging 77–110 pounds (35–50 kg).[5]

Female with characteristic tail coloring

Males re-grow their antlers every year. About 1 in 10,000 females also have antlers, although this is usually associated with hermaphroditism.[6] Bucks without branching antlers are often termed "spiked bucks". The spikes can be quite long or very short. Research in Texas has shown that the length and branching of antlers is genetic and can be influenced by diet. Healthy deer in some areas that are well fed can have eight point branching antlers as yearlings (one and a half years old).[7] 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. Many say that deer that have spiked antlers should be culled from the population as they are not as large or as hardy as bucks with branching antlers, and never will be, but this is only true in areas where the deer's complete nutritional needs are met, which is only a small percentage of their range.[8] Spike deer 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 a 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.

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.

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.[9]

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 (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.

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, 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 that are surrounded by lowland deserts. 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.

Male white-tail in Kansas

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 (e.g., Yoho National Park and Kootenay National Park), white-tailed deer are shy and more reclusive than the coexisting mule deer, elk, and moose.

Since the second half of the nineteenth century, white-tailed deer have been introduced to Europe.[10] A population of white-tailed deer in the Brdy area remains stable today.[11] 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, cactus, and grasses. They also eat acorns, fruit, and corn. Their special stomach allows them to eat some things that humans cannot, such as mushrooms that are poisonous to humans and Red Sumac. Their diet varies in the seasons according to availability of food sources. They will also eat hay and other food that they can find in a farm yard. Whitetail deer have been known to opportunistically feed on nestling songbirds, and well as field mice, and birds trapped in Mist nets.[12]

There are several natural predators of white-tailed deer. Gray wolves, cougars, American alligators and (in the tropics) jaguars are the more effective natural predators of adult deer. Bobcats, lynxes, bears and packs of coyotes usually will prey on deer fawns. Bears may sometimes attack adult deer while lynxes, coyotes and bobcats are most likely to take adult deer when the ungulates are weakened by winter weather.[13] The general extirpation of natural deer predators over the East Coast (only the coyote is now widespread) is believed to be a factor in the overpopulation issues with this species. Many scavengers rely on deer as carrion, including New World vultures, hawks, eagles, foxes and corvids (the latter three may also rarely prey on deer fawns).

Behavior and reproduction

These bucks were pursuing a pair of does across the Loxahatchee River in Florida— the does lost them by entering a Mangrove thicket too dense for the buck's antlers

Females enter estrus, colloquially called the rut, in the fall, normally in late October or early November, triggered mainly by declining photoperiod. Sexual maturation of females depends on population density as well as availability of food.[14] 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.

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 degrees Fahrenheit, 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 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.

White-tailed deer communicate in many different ways using sounds, scent, body language, and marking. 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. Does also bleat. Grunting produces a low, guttural sound that will attract the attention of any other deer in the area. Both does and bucks snort, a sound that often signals danger. As well as snorting, bucks also grunt at a pitch that gets lower with maturity. Bucks are unique in their grunt-snort-wheeze pattern that often shows aggression and hostility. Another way white-tailed deer communicate is with their white tail. When a white-tail deer is spooked it will raise its tail to warn the other deer in the area that can see it.

Though human encounters are rare there are only an average of four cases of human casualties each year in the highly populated areas such as Minnesota, North and South Dakota, and Wisconsin. Usually, white-tailed deer will not approach a human unless it smells a bucks urine on the person.

Male white-tailed deer (Florida Keys subspecies) before breeding season with antlers still in velvet.

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 pre-orbital glands (in front of the eye) were rubbed on tree branches; recent 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.

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.

Human interactions

A white-tailed deer in Golden Valley, Minnesota
Deer spotted in a suburban development outside Montpelier, Vermont

A century ago, commercial exploitation, unregulated hunting and poor land-use practices, including deforestation 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. Recent 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 carrying capacity and the animal may be considered a nuisance. 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[15]. At high population densities, farmers can suffer economic damage by deer depredation of cash crops, especially in corn and orchards. Deer can prevent successful reforestation following logging, and have impacts on native plants and animals in parks and natural areas[16]. Deer also cause substantial damage to landscape plants in suburban areas, leading to limited hunting or trapping to relocate or sterilize them.

In the US, the species is the state animal of Arkansas, Illinois, Mississippi, New Hampshire, Ohio, Pennsylvania, Michigan, and South Carolina as well as the provincial animal of Saskatchewan. It is one of the state animals of Louisiana. The profile of a white-tailed deer buck caps the Vermont coat-of-arms 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. It is also the provincial animal of Finnish province of Pirkanmaa. Texas is home to the most white-tailed deer of any other 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, New York, North Dakota, Pennsylvania, and Indiana also boast high deer densities. In many U.S. states and Canadian provinces, hunting for white-tailed deer is deeply ingrained in local cultures and is central to the economy of many rural areas. 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.

References

  1. ↑ Gallina, S. & Lopez Arevalo, H. (2008). Odocoileus virginianus. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 8 April 2009. Database entry includes a brief justification of why this species is of least concern.
  2. ↑ White-tailed deer, Mammals Species of the World. 3rd. ed.
  3. ↑ Cervidae, Deer's Life
  4. ↑ ADW: Odocoileus virginianus: Information
  5. ↑ White-tailed deer and red brocket deer of Costa Rican Fauna
  6. ↑ Wislocki G.B. 1954 Antlers in Female Deer, with a Report of Three Cases in Odocoileus. Journal of Mammalogy 35(4):486-495.
  7. ↑ http://www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_rp_w7000_0827.pdf
  8. ↑ http://www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_lf_w7000_0247.pdf
  9. ↑ Nelson, Richard. Heart and Blood, Living With Deer In America, Chap. 1
  10. ↑ Erhardová-Kotrlá, B., 1971. The occurrence of Fascioloides magna (Bassi, 1875) in Czechoslovakia. Academia, Prague, 155 pp.
  11. ↑ Biolib-Czech Republic, Odocoileus virginianus
  12. ↑ http://www.bioone.org/doi/full/10.1674/0003-0031(2000)144%5B0419%3AWTDOVP%5D2.0.CO%3B2
  13. ↑ http://animaldiversity.ummz.umich.edu/site/accounts/information/Odocoileus_virginianus.html
  14. ↑ "Forest Foods Deer Eat," Department of Natural Resources website. http://www.michigan.gov/dnr/0,1607,7-153-10370_12148-61306--,00.html
  15. ↑ Warning to Motorists: Fall Is Peak Season for Deer-Vehicle Collisions, Insurance Information Institute, October 1, 2009
  16. ↑ Côté, SD, TP Rooney, JP Tremblay, C Dussault, and DM Waller. 2004. Ecological impacts of deer overabundance. Annual Review of Ecology Evolution and Systematics 35: 113-147.

Further reading

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