White-tailed Deer

Whitetails, extremely adaptable animals, can live in a variety of habitats; the Texas Hill Country is home to about half of the state's more than 4 million deer.

A large conspicuous tail, usually ten inches or more in length, gives the white-tailed deer its common name.  This tail, which is held erect when the animal is nervous or frightened, serves as a warning "flag" to other deer nearby. Whitetails are extremely adaptable animals and can live in a variety of habitats from pine and oak woodlands to meadows and even sand hills. Wherever they live, they are considered resident animals and have restricted home ranges. Studies in Texas have shown that most white-tails spend their entire lives within a mile and a half to three miles of their birth place, traveling farther only during the breeding seasons.

Woody vegetation is a basic habitat requirement, and deer eat mostly browse (leaves, twigs, young shoots of woody plants, and vines) and forbs (weeds and other broadleaf flowering plants). They eat very little grass, and usually only when it is green and tender. Acorns also are an important food when they are available.

During the first few months of life a fawn usually remains hidden, camouflaged by its spotted coat, and does not wander far from the spot where it was born.

Deer have a very high reproductive potential, and most mature females, called does, will breed each year, giving birth seven months later. Most does, when they reach about one and a half years of age, give birth to a single fawn. From then on, if enough food is available, the doe will have twin fawns each year until she is six or seven years old.

The fawn is inactive, isolated, and bedded down for the first few days of its life, except for the short periods when the doe visits to nurse and groom it. Its white-spotted, rust-colored coat helps it blend into its surroundings, and its near lack of scent helps protect it from predators. The fawn's spotted coat is shed three or four months after birth. Twins usually bed down separately, but the doe may bring them together for the nursing periods. During the first few months the fawns usually remain hid-den and do not wander far from the spot where they were born. As they grow older, they accompany the doe for greater distances and longer periods of time, and by fall they travel everywhere with her. They remain with her until the next year, when she drives them away before giving birth again. A deer can live for about ten years in the wild if it avoids diseases, parasites, accidents, predators, and hunters. However, by the time it reaches eight or nine years of age, its teeth may be worn to the gumline and some may be missing. Old deer without adequate teeth cannot chew well, especially the less desirable food that must be eaten when range conditions are poor. In captivity under controlled conditions, a deer can live for fifteen to twenty years.

With the exception of the bison, deer were the most important animal resource in frontier America, and both Indians and pioneers were fed and clothed by it. The white-tailed deer is still the most popular big game animal for modern-day Texas hunters, and although few hunters use its hide for clothing, most of them still enjoy eating its meat, known as venison. Some are most interested in collecting the deer's antlers (the bony growths produced each year by the male deer) and hunt only those bucks with the largest "trophy" racks.

When startled or threatened, the white-tailed deer leaps into action, often lifting its tail to expose the white underside while running for safety. With hairs erect, the tail makes a conspicuous splash of white. It may serve as a warning to other deer or as a beacon to guide the fawns that may be bounding along behind a doe.

Let's take a closer look at antlers, which are grown by members of the deer family (deer, elk, moose, and caribou), and at horns, which are grown by some other mammals. Horns and antlers are both hard objects that protrude from the heads of various mammals, but the two growths are not alike. A horn has a bony center or core. From the base of it grows a covering of hardened, modified cells called keratin. (Keratin also is found in such things as hair, fingernails, beaks, claws, hooves, snakeskins, and armadillo shells.) Horns are rarely shed and usually continue to grow throughout an animal's lifetime. Both males and females may have them, but the female's usually are smaller and less impressive. Most hoofed animals – such as cattle, sheep, goats, and their wild relatives – grow horns. Pronghorn antelope also grow horns, but theirs are slightly different. They, too, have a keratin sheath covering a bony core, but a new sheath grows each year, pushing off the old one shortly after the breeding season is over. The male's horns are branched (pronged), while the female's are smaller and seldom pronged.

Unlike horns, antlers are solid bone and are grown only by members of the deer family. Normally only the males grow them; however, female reindeer and caribous are exceptions. These females generally use their antlers to push others away from the best feeding spots, especially when food is scarce. Males primarily use their antlers for fighting each other during the breeding season. Moose antlers, which measure as much as seven feet from tip to tip and weigh more than forty-five pounds, are the largest modern specimens, but the extinct Irish elk's were even bigger. Antlers from this elk, found buried in the peat bogs of Ireland, measured eleven feet from one side to the other. The impressive size of some antlers becomes even more amazing when we discover that antlers are shed each year after breeding season and must be replaced with a new set grown the following year.

A spike buck – one that grows antlers with no forks or points – is usually genetically inferior to the fork-antlered buck and will seldom catch up in terms of body weight or antler development.

To understand just how antlers develop, let's follow the growth cycle of a normal, well-fed, male white-tailed deer. As we join him during the breeding season, his antlers are fully developed – the hard, polished weapons of a lusty warrior competing with other bucks for available females. The antlers are solid calcium, so no bleeding occurs if one of the points (tines) is broken during combat. When you consider the impact on the tines as the bucks clash together and thrash around, it is surprising they are broken so seldom. Breeding hormones keep the antlers firmly attached to the head; however, as the breeding sea-son draws to a close, production of this hormone stops. The bone at the antler base (pedicel) then begins to erode or wear away, and the antlers drop off. Shedding takes place from mid-January to mid-April, but most mature bucks in good physical condition have dropped their antlers by the end of February. Young bucks usually are a little slower. Once a buck is full-grown he will normally establish a pattern of dropping his antlers at the same time each year.

When the antlers are shed, a slight amount of blood oozes from the spots where they were attached. Scabs quickly form over the raw pedicels, and before long only scars remain to mark where the antlers were. Once the pedicels are healed, new antler buds form, and the buck begins growing next year's rack. This growth is initiated by the buck's pituitary gland, which is stimulated by increasing hours of daylight. Growth is extremely rapid and requires a tremendous amount of food. If the buck is able to find enough high-quality, protein-rich browse to satisfy his increased appetite and antler-growing needs, he can produce a full rack in about three months.

Since young deer, like teenagers, are still growing and developing their bodies, the majority of their nutritional energy is directed toward body development, and only the leftover energy goes to antler development. For this reason, a young buck's antlers are small and may have only one fork. Mature bucks need less nutritional energy to maintain their bodies, so they have more energy available for antler growth. They can produce a large rack with many points, or tines, each year. Deer that grow antlers with no forks or points are called spike bucks.

From the time the new antlers be gin growing from the pedicels until they reach their full size, they are covered with a soft skin called "velvet." Tiny blood vessels in the velvet bring food and minerals to the growing antlers. If you were able to touch this velvet, it would feel very warm because of all the blood flowing through it. This velvet covering also may help keep the deer cooler in the summer by bringing some of the animal's body heat to the surface where it can escape. An antler in velvet is soft, tender, easily injured, and will bleed if cut. Bucks make every effort to protect their growing antlers; a serious injury could produce a deformed set. Once the three-month, rapid-growth period is over, the antlers begin to harden (mineralize) beneath the velvet.

By September the fully developed antlers have hardened, and the buck's body starts getting ready for the breeding season. His complex hormone balance changes, and the blood supply to the antlers is cut off. The unnourished velvet dies and begins peeling away from the hardened antlers. As the buck rubs his antlers on trees and brush, he eventually rubs off all the velvet, but until this is accomplished, it is not unusual to see bucks running around with shreds of dried velvet hanging from their antlers. Once more, majestic, polished antlers adorn the buck's head when the breeding season starts. Then, if the buck is not harvested during the hunting season, he will again shed his antlers, just as he did the year before.

By this point you may be wondering what happens to all those antlers the bucks are shedding each year and why you haven't found any lying around in the woods. Once antlers are shed, they don't last long in the wild. Since they are storehouses for mineral salts so prized by rodents, they quickly become food for mice, rats, squirrels, and porcupines. As these animals nibble away, the antler's calcium and phosphorus provide nourishment, and the gnawing action it-self helps keep the rodent's teeth worn down. Those antlers not eaten are bleached, softened, and weathered away by the sun and rain until they become part of the soil. Their minerals may one day provide the nourishment for a plant that will be eaten by a buck and in turn provide nourishment for his growing antlers. So go the cycles of nature.

Additional Information:

Ilo Hiller
1990 – White-tailed Deer: Introducing Mammals to Young Naturalists. The Louise Lindsey Merrick Texas Environment Series, No. 10, pp. 15-20. Texas A&M University Press, College Station.