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Nature Notes: White-Tailed Deer, part two

Ed Robinson
March 28, 2015

A mature whitetail buck is a fascinating creature, the subject of a great deal of research, many hours of television programs and millions of printed words in scientific and sporting publications. Much of the focus is upon the headgear a buck develops each year, his antlers or “rack.”

whitetail buck looks at camera

Whitetail buck with long spikes (Ed Robinson photo)

The antlers are made of mineral-rich bone, and their production is a wonder of biology. At the top of a buck’s head, between the ears, are two special attachment points called “pedicles.” A male fawn will generally develop two small lumps on top of these pedicles by his first autumn. In early spring, as the buck finds better nutrition, these pedicles begin to form cartilage covered by a soft, blood-rich skin called “velvet.” Over the course of several months, the antlers grow and take shape, with the cartilage gradually turning into bone. If the pedicle or the soft antlers in velvet are damaged, the resulting rack will often become misshapen or even separate from the pedicle. Every rack is unique, and will generally grow and branch out with each passing year until a buck reaches his physical peak at six to eight years, with some sporting massive antlers that are the stuff of dreams for hunters. The biological demand upon a buck to grow these antlers is considerable, so nutrition and health play a major role in their final size and mass, along with the buck’s genetics.

In early fall, when the antlers are fully formed, blood stops flowing to them and the velvet begins to dry out. At this time of year, it is common to see bucks walking around with strips of velvet hanging from their rack, and they spend considerable time rubbing their antlers on trees and shrubs to remove the velvet. The antlers will take on a range of colors, depending upon the type of vegetation used for this rubbing. The antlers, once cleaned and hardened, become an important factor in the autumn breeding season.

Approximately 1 in 10,000 non-male deer will also develop small antlers, most of them does, a few of them hermaphrodites. An unusual doe over 200 pounds was harvested in Maine last autumn with a sizable eight-point rack.

Most of the year, whitetails are placid and secretive animals, but when the days shorten in late October or early November, everything changes. The breeding season, or “rut”, brings increases in hormone levels for males and females, with resultant changes in behavior. Bucks become far more active at all hours of the day, as they range far and wide for does, sometimes travelling 20 miles or more in a day, using their nose to find the right female. A doe in heat can attract multiple bucks, and the competition to breed can result in serious physical battles as bucks try to show dominance. Observers have reported fights lasting an hour or more, until one buck is exhausted, injured, even killed. After several weeks of this behavior, the does are happy to be left alone, and bucks have little time to rest and rebuild their energy reserves before full winter weather arrives.

In winter, after all does have been bred, bucks begin to shed their antlers. Because the antlers are rich in calcium and other minerals, they are eagerly sought out for nibbling by mice, squirrels and other rodents (deer have also been observed chewing and licking shed antlers). Collectors search far and wide for these shed antlers, both for display purposes, and to sell to Asian markets where antlers are valued for their reputed aphrodisiac qualities.

Whitetails have several methods for communication among themselves, using sounds, body language, scents and sight. Like humans, deer make sounds that are unique to each animal, allowing mothers to find their offspring when other deer are nearby. Fawns make a high-pitched bleat to locate their mothers, or to appeal for help when threatened. Adult deer use a range of grunts and wheezes to signal dominance, irritation, uncertainty, danger or an interest in breeding. Close observation of whitetails over time will reveal a wide variety of body positions that reflect their attitudes, from relaxed grazing in a meadow, to an erect neck and head with ears turned toward a noise of concern, to the stomping of front feet indicating a readiness to flee.

Deer have several scent glands located on their foreheads, the inside of their hind legs and between the hooves on their feet.  Secretions from these glands are deposited on tree limbs, or on the ground, sometimes mixed with urine that contains hormones and pheromones. With their keen sense of smell, deer are constantly searching for these scents to see what other deer have been in the area, while staying alert to odors left by predators, including humans. In the fall, bucks will “rub” their antlers to scar or remove the bark on tree trunks, leaving highly visible marks as a signal to other deer, while depositing personal scents. In the run up to the rut, deer will dig out large patches of earth with their hooves, and mark these “scrapes” with urine and scents to attract other deer.

Members of the deer family have long served as an important source of protein, hides and tools for Native Americans, and later settlers from Europe. By the Depression years, growing human populations and unregulated hunting had reduced the deer population to crisis levels. Thanks to the efforts of conservation and sporting groups, deer numbers have made a remarkable recovery across the country, with recent population estimates as high as 30 million. With changes in farming and timber practices, and the reduction in predators such as the wolf and cougar, many parts of the country are now experiencing deer numbers at nuisance levels. In areas like national parks and suburban neighborhoods where hunting is limited, too many deer can have severe impacts on native plants, forest regeneration and other animals that depend upon the same foods. Deer also play a role in the life cycle of the deer tick that we all detest.

Click here for part one of the series about deer.

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