Physical Description

Scientific name: Odocoileus virginianus

Family: Cervidae (includes deer, elk, moose and caribou)

Subspecies: There are 38 subspecies of white-tailed deer in North America and South America. The subspecies that occurs in Illinois is Odocoileus virginianus borealis.

Distribution: The distribution of white-tailed deer covers parts of Canada, throughout much of the contiguous United States, Mexico, Central America, and in the northern part of South America. White-tailed deer are found throughout Illinois.

Physical Description: Due to the abundance of food and the generally mild winters, deer in Illinois do not need to migrate and they are typically in good physical condition. This leads to strong yearly reproductive and survival rates—females often have multiple fawns and most of the adult deer survive the winter.

Deer vary in size depending upon the region. This is related to soil fertility, which provides the nutrient base for the plant communities that deer feed on.

Average Height: 3–4 feet tall at the shoulder

Average Weight: female 100–150 pounds, male 150–250 pounds

Coat

Hair is reddish-brown to tan; in winter it turns to grayish-brown.

Throat, belly, inner rump, insides of the legs, and underside of the tail are white.

In Illinois, molt from winter to summer coat generally occurs in April and back to winter coat in September. The summer coat has finer hairs for better cooling, but less protection from insects. The winter coat consists of brittle, hollow guard hairs that contain air which provides insulation and buoyancy for swimming.

Two images of deer next to each other. The deer on the left has reddish fur in the summer, and the deer on the right has grey-brown fur in the winter.
The female on the left has the classic summer coat while the female on the right has the thicker, gray-brown winter coat.

Fawns are completely covered with hair when they are born. Their reddish coat has 250–350 white spots that creates a mottled pattern that blends with their surroundings, providing camouflage from predators. At 3–5 months of age they develop a coat similar to the adult winter coat.

Antlers

Adult male with antlers.
Photo: Chris Young

Antlers are solid bone formations, not hollow like horns. They develop from the skin-covered pedicle on the frontal bone of deer’s skull.

Antler growth is regulated by the melatonin hormone which is controlled by day length. Antlers begin developing in early spring and typically shed between late December and mid-March.

Antler shape, size, and composition is an expression of the genes received from the male’s parents, as well as nutrition and his age.

For additional information, refer to Nutritional Requirements of White-Tailed Deer in Missouri.

Growth

Two photos of deer. The top photo is of a male deer's antlers which are still covered in velvet. The bottom image is of a male fawn that has two protrusions called buttons on its head where its antlers will grow.
Top photo: Male in velvet. Bottom photo: This male fawn has buttons where the antlers will come in.
Photo: courtesy of Illinois Department of Natural Resources

During the active growth phase, antlers have a rich blood supply and are covered with short, bristly hairs known as velvet.

Growing antlers are composed primarily of proteins along with calcium, phosphorus, and smaller amounts of other minerals.

Antlers become larger and heavier each year starting with buttons on a male fawn at 4–5 months and developing to the full rack developed by 6½ years.

The rack of a deer more than 6½ years of age usually loses its symmetry. Instead of the standard branched beam, it may develop many small tines.

Shedding

By late summer, blood flow to the antlers ceases causing the velvet to start drying out. Males begin rubbing off the sloughing velvet, polishing the hardened antlers in the process. Hardened antlers have low water and protein content, weakening the connection between the antler and skull which leads to shedding the antler. Most antler shedding occurs between late December and mid-March. Shed antlers usually do not last long because rodents gnaw on them for their mineral content, and weather softens the antler, returning the nutrients to the forest floor.

Deformed Antlers

Non-typical antler growth may be a result of genetics or injury. When genetically related, abnormal branching often occurs on both antlers. Antlers are most vulnerable to injuries during the growth stage. Deformation caused by injury can be permanent or temporary. Occasionally, antlers of some deer appear palmated —filled in between the tines like a moose—which is an inherited trait.

Male deer with a deformed antler sits in a soybean field.
Male with a deformed antler.
Photo: courtesy of Illinois Department of Natural Resources

Antlered Females

The uncommon females with antlers are of two types: those with velvet-covered antlers and a female reproductive tract able to bear young; and those with polished antlers that are male pseudo-hermaphrodites and have the external genitalia of a female but internally possesses male organs. Females that lack the ability to regulate the hormone testosterone may grow antlers.

Collecting Shed Antlers

Video about collecting antler sheds in Illinois (2:04 minutes).

Go to the Illinois Hunting Digest for current rules on collecting shed antlers.

Senses

Smell

Studies have shown that deer can detect human scent on underbrush for days and that cautious males react negatively to the scent, often remaining wary of the area for weeks. Deer can detect odors over 100 times better than people because they have millions more nasal receptors that helps them distinguish between odors.

Hearing

A deer’s ears can move independently to focus on sounds. Deer have better high-frequency hearing than humans but poorer low-frequency hearing.

Sight

  • Large eyes on the sides of the head allow deer to see ahead and behind without moving their heads, giving them approximately a 310˚ field of vision.
  • Their eyes are highly sensitive to light, and they can see well during the day and at night.
  • While white-tailed deer generally see in shades of gray, they are able to distinguish shades of blue, yellow, and green, but are less able to distinguish in the orange and red wavelengths.
  • Deer hunters wear blaze orange and blaze pink because both colors stand out to people, but deer are unable to see these colors.
  • A tissue (tapetum) in a deer’s eye enhances vision in low-light conditions. When a light is shone in their eyes, the captured light is reflected back through the retina making the eyes shine.

Vocalizations

Deer make a range of vocalizations, including, but not limited to:

Bleats—Fawns bleat like lambs.

Blows—Males and females may blow or whistle.

Grunts—Males often call during the mating season.

Snorts—Alerts the herd of an approaching threat.

Snort-wheeze—Classic noise males make during the breeding season.

Glands

Odors from the skin glands provide a means of communication between deer.
Photo: Graphic courtesy of Sarah Marjanovic

Forehead: Glands located on the foreheads of deer leave a scent behind when they rub on vegetation. All deer use these secretory glands during the rutting season, but dominant males make the most use of them.

Preorbital: These glands are located in the forward corner of the eye, and gland secretions serve to cleanse the eye.

Nasal: Scientists are uncertain as to its purpose other than lubricating the nose.

Preputial: This gland is located inside the penis sheath and consists of greatly enlarged sebaceous glands.

Tarsal: Located inside the hind leg at the hock, or crook, of the leg, this gland plays an important role in communication, social dominance, and reproductive activities and is considered the most important gland. Deer urinate with their legs together, rubbing while urinating over the glands. Males use this behavior to display social dominance. Incidentally, removal of the tarsal or metatarsal glands upon killing a deer is unnecessary because all functions cease once the deer is dead. By cutting these glands, the knife can become contaminated and spread scent throughout the rest of the carcass and spoil the meat.

Metatarsal: This gland is located on the outside of the hind leg, above the toes of the deer, and is ringed with white hair. The role they play is uncertain.

Interdigital: The interdigital glands, found between the toes on each foot, are used by deer as an aid in tracking other deer. As the hoof is carried through vegetation or placed on the ground, scent from a waxy secretion is left where the deer has walked. This can be used as a means for does to track their young or for bucks trailing does during rut. Dominant males have higher concentrations of certain compounds in their gland’s secretions than subordinate males, thus informing other deer of their social status.