Deer vary in color shadings from area to area.
They also vary with the season. All whitetails shed twice a year. In the
spring, they get a new coat that is a bright reddish-brown, the hair solid
and thin. As cold weather approaches in the fall this hair is replaced
by the winter coat, which shades from bluish to a grayish-brown. The winter
hair is long, kinky, and filled with air pockets providing excellent insulation.
I have often seen deer whose bodies lost so little heat that snow and
sleet did not melt on their backs but remained encrusted on the hair.
Despite regional differences, deer are colored
basically alike. They have a jet-black nose with two white bands behind
it. The face is brown, the eyes circled with white. The insides of the
ears, beneath the chin and the large throat patch are pure white. The
body is darkest down the middle of the back, shading lighter till it abruptly
reaches the white stomach. The upper portion of the legs on the outside
are brown and the insides are white. The top side of the tail is brown
with some having various amounts of black at the tip. The underside of
the tail and rear portion of the deer is a sparkling white. Like the pronghorn
antelope, the whitetail can erect and flare its rump hairs when alarmed.
However, bucks do not flaunt their tails as commonly as do the does. It
is thought that does do this to guide their young as they flee from danger
through the dark night or deep forest. When the deer clasps its tail down
tightly and keeps the rump hairs bent inwardly, it is almost impossible
to see any of the telltale white. Halfway between the toes and the heel of the
foot on the outside of the hind leg, the deer has a metatarsal gland.
Of the three deer found in the United States, the whitetail has the smallest
metatarsal gland. The size of this gland is often used as a means of identification
if only the legs are available. Supposedly this gland also gives off a
musk; its purpose is not well understood. At the deer's hock on the inside
of the leg is the tarsal gland. This gland plays a very important sexual
role. In addition to giving off a strong musk, which is attractive to
other deer, both bucks and does bend their legs together and Curve their
bodies so that they urinate on the hair tufts covering the glands. In
front of the deer's eye is the lachrymal or preorbital gland. This gland
is used to mark bushes and over hanging limbs by bucks which also plays
a pivotal part in the sexual life of a whitetail. Skeletal System: Buck deer have antlers for the main purpose of
fighting other bucks during the breeding season. Recent research shows
that the antlers may also be an erotic stimulant. Most bucks lose their
antlers during the months of December or January. They have nothing but
the antler bases, called pedicels, on their heads until April. During
this month, these bases start to swell with the growth of new cells. Horns
that are not shed, such as those on mountain sheep, have a center core
filled with blood cells which foster growth. Antlers of the deer are solid
and nourished externally by a network of blood vessels called "velvet."
Musculature System: Fat Deposits: Fat levels in deer depend on nutritional
and social conditions, and sex, age, and season. Fat is stored first in
the bone marrow, then deposited around the kidneys intestines, and stomach
cavity, in that order. Mobilization of fat reserves should follow in reverse
order. Fat that infiltrates bone marrow changes the color and texture
of the marrow, making it possible visually to estimate the grade of fat
present. Femur marrow generally is used for fat analyses. According to
the study of Stockle et al. (1978), measurement of bone marrow fat can
be improved using the ''Hobart Percentage Fat Indicator." Marrow
fat itself was not found to be a reliable indicator of physical condition
in deer. Circulatory System: Heart. Whitetail Deer, like most mammals, have
a four chamber heart which circulates blood through the circulatory system.
It transfers oxygen and nutriants throughout the body and carries away
carbon monoxide and waste materials for disposal. Lungs. The Whitetail's Lungs perform the same
function as in all mammals, transfering oxygen into and carbon monoxide
out of the blood circulated through the alveoli. Spleen. The spleen is an important producer of
blood cells--primarily Lymphocytes. Erythrocytes can be stored in large
amounts. The spleen of deer belongs to the blood-storing type, which is
characteristic of endurance runners. Therefore, spleens of animals that
die minutes after being wounded will be of much lower weight than spleens
of animals that die instantly. The members of the deer family are ruminants,
having a four-compartmented stomach, which allows the deer to feed very
rapidly, chewing its food just enough to swallow it. This partially chewed
food goes into the storage section of the stomach known as the rumen.
A feeding deer is at a disadvantage because while feeding it cannot be
alert to danger. Not having to masticate its food thoroughly, the deer
can fill its paunch rapidly and then retire to a safe place to do the
job properly. When the deer is ready, it regurgitates a ball of partially
chewed food about the size of an orange and re-chews it, then re-swallows
the food, which now enters the second section of the stomach, the reticulum.
From there, it goes into the omasurn, then through the abomasum into the
intestines where digestion is completed. Deer do not have a gall bladder on their livers.
This allows them to eat vegetation that would kill domestic animals. Deer are ruminants, meaning they are equipped
with a four-chambered stomach. An interesting characteristic about the
ruminant's stomach is that it allows the animal to gather a lot of food
at once, then chew, and digest it later. The four chambered stomach is
needed to process the large quantities of low nutrient food the deer eat.
Depending on the type and abundance of food,
the deer can fill its stomach in about one or two hours. When a deer eats,
food is moved by the tongue to the back of the mouth, where it is chewed
just enough to swallow. The food then passes down the gullet into the
stomach. After the deer has filled its paunch, it lies
down in a secluded place to chew its cud. After chewing its cud for awhile,
the deer re-swallows the food, which then passes to the second portion
of the stomach, the reticulum. The reticulum has a lining that looks like
a honeycomb. The reticulum holds the food in a clump, which can grow to
the size of a softball. The main function of the reticulum is to filter
out any foreign material. After about sixteen hours, the food passes to
the third chamber, the omasum, where intensive digestion and absorption
take place. The omasum's lining has forty flaps of varying heights, which
absorb most of the water from the food. The last compartment, the abomasum, has a very
smooth, slippery lining with about a dozen elongated folds. The abomasum
produces acid to break down the food pieces for easier absorption of nutrients.
Deer Anatamy
Evolutionists believe the ancestors of the deer originally had five toes
on each of their feet. Through evolution, the first toe corresponding
to our thumb disappeared entirely. The second and fifth toes diminished
in size and moved to the rear where they now function as dewclaws. The
third and fourth toes became enlarged and form the main hooves as we know
them today. Actually, the deer walks on its toenails instead of its toes.
This type of foot is very efficient for fast movement over well-packed
earth. Between the center hooves is the interdigital gland, which gives
off a yellow, waxy substance that marks the ground as the deer walks.
This enables the animals to track one another, particularly the doe to
follow a straying fawn. Of course, it also enables predators to track
the deer. 
Digestive System:
The four sections of a deer's stomach are the rumen, the reticulum, the
omasum, and the abomasum. First, the food goes into the rumen which stores
8 to 9 quarts of unchewed food and acts as a fermentation vat. Most of
the digestion occurs in this area of the stomach. Deer depend on billions
of microorganisms that live in its stomach. These microorganisms
break down the fibers, cellulose, and other basic plant components, and
convert them into materials that can be used by the deer's digestive system.
The lining of the rumen has small spaghetti-like fringes called papillae,
which vary in length from 3/8 to 1/2 inch. Over 40 percent of a deer's
energy is derived from the acids absorbed through the papillae and the
walls of the rumen.
The food eventually passes through 67 feet of intestines, where most of
the liquid is absorbed, leaving an impacted mass of undigested particles.
These particles are passed out as excrement. A deer goes to the bathroom"
an average of 13 times every 24 hours. Usually 65 percent of the food
will be used by the animal, and 5 percent is lost as methane gas, 5 percent
as urine, and 25 percent as feces.