Whitetail Deer Biology

[letinmfly]

Not sure if this is the right place to post this but here goes.  Makes for intersting reading especially for young/new hunters.

Whitetail Deer Biology    HISTORY

Class: Mammalia, Order: Artiodactyla. Family: Cervidae, Sub Family: Capreolinae, Genus: Odocoileus, Species: virginianus. The whitetail deer gets its name from its large whitet tail it flags when it senses danger and escapes.

Whitetailed deer are of considerable economic importance as a big game mammal. Sportsmen prize this unique species for a number of qualities, including large body size, tasty venison, and the ability of mature bucks to develop an attractive and often massive set of antlers. Overall this mammal is one of the most hunted and most prized animals in North America today.

For the Indians and early settlers, deer provided food; hides for clothing, shelter and bedding; sinews for bowstrings and implements of war, fish lines and the stitching of bark utensils; brains for bleaching and tanning; and bones and antlers for awls, needles, scrapers, implement-making tools and ornaments.

Deer now provide us considerable food, sport and pleasure. Since approximately 57 percent of the live weight of a deer is edible, the venison acquired from legal hunting provides many pounds of meat. The tanned hide, or buckskin, has a limited use for sport jackets and gloves. Deer hunting has become a big commercial enterprise and a source of income to many: to manufacturers of arms, ammunition and hunting apparel as well as to persons providing food, lodging, transportation and a place to hunt. From another dollars-and-cents angle, deer can be considered an asset to vacation sites as their attractive presence influences the stay of visitors in an area.

Where deer populations are heavy, their feeding may damage domestic crops and the understory of forested lands.

SPECIES OF WHITETAIL DEER

PHYSICAL DESCRIPTION

A popular game species, the whitetail is so well known that it needs only a brief description. Antlers normally occur only in males and are formed and shed each year. Growth of the antler starts in April or May when the base of the antler, located on the skull, begins to enlarge. During the growth period, the soft skin and short hair which cover each antler have a plushlike quality, giving this stage the name of "velvet." Full antler size is reached in August or September, shortly before the breeding, or rutting, season. The velvet then begins to dry and peel. The buck rubs his antlers against trees and shrubs, which helps remove the skin. When all the skin has been shed, the bony core hardens and with continued rubbing is polished. The antlers are carried in this condition throughout the rut. Sometime toward the end of the breeding season, usually from the last of December to mid-February, resorption of bone around the base causes the antlers to become loose and they are shed. After falling to the ground, they are gnawed and eventually consumed by rodents and rabbits for their minerals and protein.

Both the size of the antler and number of points depend upon many factors such as the deer's age, the quality and quantity of food, injury, hormone regulation and heredity. It is not possible to tell the age of a buck by the size of the antlers or the number of points. In their first fall, fawn bucks have "buttons" that can be felt under the skin or observed as slight swellings, or they may actually have small unbranched, or spiked, antlers that have broken through the skin. In yearling bucks, antlers are always visible externally. While some may have only the unbranched main beam at this age, most have more than one point. During the succeeding years of the buck's life, the antlers become more massive. In general, the number of points increases to a total of six to 10, but frequently a few more occur. Following the period of life when sexual activity is greatest, the size of the antlers generally dwindles with each year's renewal until an old deer may have only spikes. Abnormally shaped antlers occur occasionally and sometimes represent injury during growth. An upset in the hormone system is one factor which is probably responsible for unusual cases of antlerless bucks or for females having antlers. In some cases, antlerless bucks are the result of hereditary factors. Hunters count all of the points, including the snag on both beams, in arriving at the total number of points on a trophy set of antlers.

In summer, both sexes are reddish brown to tan above (often called the "red" coat); the color pattern of the winter coat is similar to the summer one but is grayish to grayish brown (often called the "blue" coat). Fawns are reddish, brown or reddish yellow spotted with white. They gradually lose their spots and acquire uniform coloration between 3 and 5 months of age.

The sex of a deer cannot be determined by its track, because there is no constant difference between the size and shape of buck and doe hoofs. During the breeding season, the necks of males swell to approximately twice their nonbreeding size, reaching a maximum in mid-November. The factors causing this enlargement are not fully understood.

Deer are in the prime of life between 2 1/2 and 7 1/2 years of age. Some may live for about 15 years in the wild and up to 25 years in captivity.

The tarsal glands, marked by a tuft of long, coarse hair on the inside of each hind leg at the ankle, or hock, produce an oily secretion with a pronounced ammoniacal smell. Another set of glands, the metatarsals, occurs on the outside of each hind leg between the ankle and hoof. They give off an oily substance with a pungent, musky odor which scents and possibly serves to identify the resting spots of the deer. Pedal glands, lying between the two main toes on each foot, secrete a strong and offensive odor throughout the year. This secretion is conducted to the hoofs by long hairs and doubtless scents the tracks of the animal. Small preorbital glands lie just in front of each eye. They probably scent twigs and branches where the deer feeds.

REPRODUCTION

Bucks are capable of mating successfully from September through February and possibly later, but the peak of the mating or rutting season is in November. Pregnancy lasts 6 1/2-7 months; the young are born most often in late May or early June. A doe usually has twins, but sometimes has a single offspring or triplets.

At birth, each fawn weighs between four and seven pounds (1.8 and 3.1 kg). Its eyes are open and it can stand feebly. The fawns begin to follow the doe when about 3 to 4 weeks old and start to eat their first solid foods. Weaning may begin about this time although some fawns nurse until they are 6 months old. The young continue to accompany the female until they are old enough to breed. About one-half of the young females in Missouri become sexually mature at 6 to 8 months of age and consequently breed in the year of their birth. Other females and young males breed first at 1 1/2 years of age.

DIET

Deer are browsing animals, feeding chiefly on the leaves, twigs and fruits of trees and shrubs, and the foliage of herbaceous plants. They also take seeds, fungi, mosses, lichens, succulent grasses, farm crops and sometimes small amounts of animal food like snails and fish.

Whitetails show a definite selection of plants and seemingly take first those that are most nutritious and palatable. This selectivity can have serious effects. In ranges having concentrations of deer, overbrowsing occurs. The results are a lower level of nutrition of the herd and elimination of these desirable foods from the range.

Deer require water in some form daily. They frequent any mineral licks in the vicinity, especially in spring.

DEFENSES/ENEMIES

Whitetail deer have excellent eyesight, have good hearing due to their large years and also rely upon the sense of smell in detecting danger. Stationary objects are easily overlooked by them, but they readily detect any that are in motion. Their hearing is also very good due to the large ears that they can rotate in any direction. The whitetail deer can run up to 35 mph (56 kph) for short distances.

Whitetail deer have several distinct strategies for avoiding predators. They specializes in detecting danger by means of large ears, acute snese of smell and excellent vision. Males can quickly detect and visually track another animal as far as 600 meters. Once danger is detected, they may choose to hide, or move into cover and cautiously outmaneuver the predator. Another strategy whitetails use is they may bound off and then trot away, stopping frequently to gain information on the disturbance. This initial bounding, combined with release of metatarsal scent that inhibits feeding, is highly advantageous in that, by alarming others, it causes other whitetail deer to bound off as well, reducing the conspicuousness of the deer who bounded off first. This strategy would also trigger group formation. Finally, when a predator closes in, whitetail deer initiate evasive maneuvers based on sudden unpredictable changes in direction and on placing obstacles between itself and the predator. This strategy, however, does not work against group-hunting predators.

Whitetail deer are excellent swimmers but hardly ever use this means of escape. Whitetail deer bucks will use their antlers as protection from predators. Whitetail deer will also protect themselves by rearing up and slashing out with their front hooves. The fawn's survival strategy is based on its protective coloration, its ability to remain motionless as danger approaches, and its small amount of scent which makes finding it difficult for predators.

Major predators on whitetail deer are mountain lions, which are deer eating machines, coyotes, golden eagles, feral dogs, bears and bobcats.

RANGE

In primitive times, there was an estimated population of 40 million white-tailed deer in the 2 million square miles (3,200,000 square km) of original range north of Mexico. The most populated regions were the Mississippi Valley and what is now the eastern United States. With settlement and conquest of the continent by Europeans, the deer population was greatly reduced. Between 1875 and 1915, deer were at their lowest level. Restocking and redistribution were begun around the turn of the century and, with added protection, the deer began to increase.

Coincident with the original population decline, the range also was altered. Because of destruction of large sections of the native forests and clearing for agriculture, considerable territory was lost in the east and center of the primitive range; but new areas to the north and northwest were made habitable by the favorable variety of plant growth which often followed clearing.

HABITAT

Habitat and home. Deer live primarily in timbered areas, selecting the borders or edges more than dense, uniform stands. One of the main reasons for this habitat preference is that the variety of foods deer like grows best along the margins of timbered areas or in clearings in the timber. Another reason, especially true in the more agricultural sections of the country, is that the deer can utilize the forage offered by agricultural crops adjacent to timbered lands and still have the sanctuary and other attractions of the timber itself.

They have no permanent structure for a home.

DAILY LIFE

White-tailed deer tend to have an average annual home range from 1/2-1 1/2 square miles (.8-2.4 square km). Some individuals, particularly bucks during the rut, may cover a larger area. Local movements of deer are related primarily to the seasonal changes in food sources or cover. When acorns are not abundant in their summer area, some deer may shift to localities where they are available in fall and winter.

Deer usually spend the day in concealing cover and rarely move about, but toward evening come out to feed and drink. On bright moon-light nights they may feed all night, but on dark nights they are more active in the evening and again early in the morning. During winter when food is scarce, they may feed longer hours and even during the day. In stormy, windy weather they are restless; they browse more than usual and often change their bed spot several times a day.

The location of the bed spot depends largely upon the weather. On sunny, warm days, some shady place is selected; on cloudy, windy or cool days, a sunny spot or one protected from the wind is picked out.

Bucks commonly fight each other during the rut. Only rarely, however, do their antlers become entangled permanently. When this happens, the bucks are unable to feed properly and die of weakness and starvation.

DISEASES

Ticks, lice, and nasal bots are parasites commonly found on and in whitetaildeer. Most deer commonly harbor light infestations of ticks and nasal blots, but not at levels high enough to present a health problem to the deer. Likewise, internal parasites, especially stomach worms, are common but are not at sufficient levels to cause clinical symptoms. However, the concentration of individuals at feeding sites increases the potential for disease transmission. Because disease-causing organisms can be transmitted through the soil, supplemental feed should not be placed on the ground. Some type of trough should be used and, ideally, the feeding site should be relocated every year or two. Evidence of exposure to bluetongue and epizootic hemorrhagic disease (EHD) has been documented in whitetiai deer. The most common disease agent among deer appears to be warts.

Today the major news headlines is about Chronic Wasting Disease, often referred to as CWD. CWD is a disease unique to North America. On our continent, it has been found in wild deer and or elk in Colorado, Wyoming, Nebraska, South Dakota, Wisconsin and Saskatchewan. In captive deer and or elk, it has been found in Colorado, Montana, South Dakota, Oklahoma, Kansas, Nebraska, New Mexico, Saskatchewan and Alberta.. CWD appears to be a prion disease that attacks the central nervous system and causes fatal damage to the brain of white-tailed deer, mule deer and Rocky Mountain elk. CWD is similar to, but significantly different from, scrapie (documented in domestic sheep for over 400 years), Bovine Spongiform Encephalopathy (BSE and often referred to as mad cow disease) and variant Creutzfeldt-Jakob disease found in humans. All of these diseases attack the central nervous system and cause small holes to form in the brains of infected animals.

There is currently no scientific evidence that CWD has or can spread to humans, either through contact with infected animals or by eating the meat of infected animals. The Center for Disease Control has conducted an exhaustive study of CWD and human risk and has stated: “The risk of infection with the CWD agent among hunters is extremely small, if it exists at all”. However, as we are still learning about this disease, state wildlife agencies recommend that hunters take precautions to limit risks. First and foremost, do not harvest any animal that appears sick or is acting strange. Note the animal’s location and contact the state personnel. Avoid cutting or puncturing the spinal cords or brains of animals taken in the areas where CWD occurs. Do not use house-hold utensils to field dress or process your deer. Wear rubber or latex gloves when handling any harvested animal. You should also make sure about your states current regulations regarding the importation of deer or elk meat from outside your state. Some states are also considering testing all or some of the animals taken during the hunt season for CWD.

In the later stages of infection, deer and elk infected with CWD will show signs of progressive weight loss, listlessness, excessive salivation and urination, increased water intake, depression and, eventually, death. Animals can be infected with CWD for months or years before outward signs of infection are evident.

Missouri Conservation Commission 1981

 

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