Field Guide/Mammals/White-tailed Deer
|Odocoileus virginianus (White-Tailed Deer)|
Size: Depending on the access to nutritional sources and the type of weather in each region, white-tailed deer may vary in length, width, height, weight, and antler growth. For example, male deer found in the northern United States and southern Canada range in weights of 198 to 298 pounds (89.81 kg to 135.17 kg) compared to male deer in the Florida Keys and Coiba Island who can weigh as low as 49 pounds (22.23 kg). During the summer, female deer, or does, average 99 pounds (44.90 kg) whereas males average 150 pounds (68.04 kg). The difference between sexes is that females weigh about 20 to 40 percent less than males. In addition, white-tailed deer typically range in size from 41 to 94 inches (104.14 cm to 238.76 cm) in length and 21 to 42 inches (53.34 cm to 106.68 cm) in height.
Description: The name white-tailed deer is widely accepted because their tails are brown above and white below with laterally fringed white throughout. Adults have white patches along their nose, throat, and eyes. Unlike fawns and females, adult male deer are called bucks and have antlers that branch into two parts with tines, or fork-like points, that are about equal in size. Depending on the season, white-tailed deer have different types of coats. For example, in the summer seasons, from May to June, adults have short, thin, wiry hairs that vary between the colors red-brown to bright tan. Darker hairs can be found along the middle of the back and lighter hairs can be found on the face, throat, and chest. During the months of August to September, summer coats are replaced by winter coats that range in colors from blue-gray to gray-brown. While summer coats are much thinner, winter coats are longer, thicker, and more brittle.
Similar Species: White-tailed deer can be distinguished from other species by the white hair that grows on the underside of the tail. In addition, white-tailed deer have antlers that branch out from a single beam whereas other species, like the mule deer, have antlers with tines that fork from each joint.
Range: White-tailed deer range from southern Canada throughout the United States and occupy the northern part of South America. White-tailed deer are absent in Utah, Alaska, and Hawaii and are rarely found in the states of Nevada and California. Previously, white-tailed deer were less common and did not occupy such a broad range, but after the corruption of forests and land clearing numbers rapidly increased. In order to maintain the overabundance of white-tailed deer, seasons are dedicated to deer hunting.
Habitat: White-tailed deer occupy a wide range of habitats from north-temperate and subtropical climates in North America to rainforests in Central America and northern South America. The greatest abundance of deer is found east of the Mississippi River within coastal wetlands and islands along the Gulf of Mexico and the Atlantic Ocean.
Diet: White-tailed deer are herbivores and prefer to graze on plant foods. The most common type of food white tailed deer forage for is grasses and forbs. Once vegetation matures during the late summer months, deer feed on succulent leaves and twigs. Come the autumn months, deer must rely on soft and hard fruits and acorns. In regions where snowy winters are prevalent, deer feed on dried leaves from deciduous trees, sedges, grasses, mushrooms, and other fungi. White-tailed deer that are located in farming regions eat crops like corn, soybeans, and alfalfa.
Activity: White-tailed deer are crepuscular, or active during the twilight hours. Typically, they feed at dusk but may also feed during the day or night. White-tailed deer do not hibernate in the winter and do not migrate. White-tailed deer have two basic social groups: family and fraternal. Family groups are centered around a female head and her fawns while a fraternal group is made up of male adults and sometimes yearling males. Sometimes mixed feeding groups arise which include deer of various age and sex. Unlike social groups, this grouping is only a temporary gathering. Another type of temporary gathering can happen during the winter and summer when deer use trees as protection against weather severity. These types of gatherings are called "deer yards." 
Reproduction: An average gestation period for female deer is about 202 days but varies between species. The weight, height, and length of fawns depends on the mother's nutritional availability and weather severity. Litter sizes range from one to three fawns. Fawns begin nursing immediately and continue a fast growth cycle. Upon birth, fawns weigh between 4 to 8 pounds (1.81 kg to 3.63 kg). Within the first two weeks, a fawn will have doubled in weight and tripled in weight by the end of the first month. Fawns have reddish-brown coats with white spots found along the back that disappear around 3 to 4 months. Females have the ability to breed after about 6 to 7 months but typically begin after a year and a half. Similarly, males reach sexual maturity by one and a half years. Fawns begin to accompany their mothers at 3 to 4 weeks and by 8 weeks are considered members of the female group.
Lifespan: The life expectancy of the white-tailed deer can exceed twenty years. However, most deer only make it to ten years. Incidents such as fence entanglement, automobile accidents, diseases, parasites, predation, hunting, old age, and poaching may end the life of a deer sooner than later.
Notes: White-tailed deer can cause a range of situations in which damage is done to plants, landscapes, automobiles, and even humans. Estimates say that white-tailed deer cost the forest industry $750 billion a year when they eat economically valuable trees. In addition, they eat garden and field crops, fruits, and ornamental plants that cause $100 million a year in agricultural damage throughout the United States. Car collisions are estimated at a cost of $1 billion a year nationally. Also, white-tailed deer are associated with disease risks because they serve as hosts for parasites like botflies, liver flukes, ticks, lice, and worms. The combined losses result in a $2 billion loss a year nationally and increased cases of Lyme's disease have been reported in the northeastern parts of the United States. Male white-tailed deer, or bucks, grow antlers annually. Antlers begin to grow in the summer and fall off during the winter months. Because antlers are rich in calcium, small rodents, rabbits, and porcupines feed on them once they have been shed.
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