How well do you know your prey? Even if you’re a veteran whitetail hunter, you’re probably not quite as familiar with the species as you think.
EDITOR’S NOTE — This story is excerpted from the book Whitetail Hunting: Top-Notch Strategies for Hunting North America’s Most Popular Big-Game Animal by Shawn Perich and Michael Furtman.
No hunter succeeds without complete knowledge of the animal he or she pursues.
If that’s true, then it is doubly true for the deer hunter, for the white-tailed deer is a complex animal, physically and behaviorally. You simply can’t get close enough to one of these secretive animals without knowing how it behaves, and why it does so.
As with all animals, two primary urges control the whitetail’s behavior. Food is first, for without that, there is no health. Sex is second, for once adequate food is acquired, the majority of a healthy, well-fed whitetail’s behavior revolves around reproduction.
Not just the actual sex act, mind you, but the whole cycle of reproducing. For the buck, that means acquiring the size and antler configuration to “out compete” his rivals and to attract does.
For the doe, it means being healthy enough to carry a fetus through the long winter, to give birth in spring and to ensure her fawns grow large enough to survive their first winter.
Ensuring success in these energy-intensive endeavors requires physical skills and finely tuned senses. Whitetails have all of that, the result of eons of evolution, during which they’ve been repeatedly tested by weather, predators and disease. The weak were found lacking, and the strong were not. The hunter must pit himself or herself against the result of natural selection over thousands of generations — quite a daunting task.
It may seem strange to begin a discussion on the whitetail’s physiology by looking first at its stomach, but it really is the stomach that in many ways influences the shape of everything else.
So how does a stomach influence a species? Consider this: If a deer must stand long enough in one spot to thoroughly chew its food until it is digestible, it also exposes itself to predators for long periods.
The whitetail’s compound stomach is comprised of four chambers: rumen, reticulum, omasum and abomasum. When it has consumed a sufficient quantity of food, it travels to a secure hiding area, brings the food back up, and chews its cud in relative leisure and safety.
By being able to digest and chew food at a later time, a deer can browse and move, making it a more difficult target to find.
The white-tailed deer selectively chooses more digestible plants, or the most digestible parts of plants, rather than consuming large quantities of less-digestible food. Deer rarely stand in one place for long, but prefer to nip and move.
Once they’ve temporarily eaten their fill and stored the food in the rumen (the stomach’s first chamber), white-tailed deer move to an area in their territory they consider safe. Here they bed down, and once they are confident that no danger awaits them, they regurgitate a ball, or bolus, of food for further chewing.
White-tailed deer have a highly specialized digestive system that permits both this feeding behavior and the ability to eat a variety of plant foods. Although they are, like cattle, considered ruminants, they are not true grazers as are cows.
Cattle can eat grass or other ruffage. This involves considerable “head down” grazing in order to consume the large volume of less-nutritious forage needed. A cow or bison with its head down all the time isn’t being particularly alert to threats. Herding behavior offsets this because as some animals graze, others stand by, chewing their cuds, and act as guards.
Whitetails can afford to be selective; the forest and its edge hold a wide variety of succulent plants, browse, fruits and nuts. True grazers, like cattle and bison, are animals of the plains where they feed on varieties of less-nutritious and less-digestible grasses.
The fact that deer can be choosy means they have a slightly different digestive system than other ruminants. The whitetails’ rumen is smaller than that of other deer, and their salivary glands are larger.
After carefully selecting their food, whitetails nip it from the main plant. Whitetails lack incisors on the upper jaw (and have no true canine teeth), so they shred food from the plant stem by grasping it between the lower incisors and the tough, bony roof of the upper jaw.
If you study browsed plants carefully, you’ll soon be able to distinguish those slightly shredded twig tips left by browsing whitetails from the cleanly cut tips made by other animals, like rabbits.
The whitetail’s selective feeding behavior is aided by its nimble lips and narrow face, which have evolved to allow them to “insert” their face and mouth into trees and shrubs, or among various ground plants, to select not only the species of choice, but the portion of the plant they desire.
After tearing off a mouthful, whitetails chew the food very briefly — only enough to swallow it — which is aided by the abundance of saliva whitetails can manufacture.
Then, as stated earlier, they move off to their bedding area to further chew and digest their food.
Knowing where deer bed, then, is an important bit of knowledge for the hunter. Deer repeatedly use the same bedding areas and routes to them. Once bedded, they are nearly impossible to find, so the hunter’s best chance is to waylay the deer on its way from a feeding area to the bedding grounds.
With its stomach dictating that it be fed, almost everything else about the deer’s body is designed to facilitate that. Feet, legs, joints, bones — all are designed to get a deer quietly around the forest so that it can find the food its stomach demands, and to get it out of trouble should trouble find it.
Its fine array of senses evolved to provide it with an early-warning system, and to utilize the chemical messages left by its glandular system.
Speed and stealth for whitetails begin “where the rubber meets the road” — in their case where the keratin meets the detritus (OK — in lay terms, where the outer hoof meets the decaying material that makes up the Earth).
Hooves and Legs
The whitetail’s narrow, tapered hooves are specialized to allow minimal contact with the ground. That serves deer well in two ways: Minimal contact reduces friction, which increases speed; and narrow hooves are easier to place quietly amidst the forest floor’s noisy leaves and sticks.
In addition, whitetails are “perfect walkers,” which simply means that while walking at normal speed, the rear hooves fall exactly into the tracks of the front hooves. The advantage of this seems fairly obvious: Once the front hooves have been safely and quietly placed, the deer knows that its rear steps will be equally well placed.
The track of a whitetail hoof is like that of paired commas. Looking at a whitetail’s tracks, one would easily assume that it only has two toes per leg. If you guessed that, you’d be exactly half right, since there are two other vestigial toes farther up the back of the leg, known as dewclaws. The front legs’ dewclaws are nearer to the hoof than those of the rear. Usually dewclaws don’t show in tracks unless the deer has been walking in snow or mud, or running at high speed.
When walking, the closed, rounded point of the track faces forward. However, at full gallop, or braking down a steep embankment, deer splay their hooves wide at the front, reversing the impression. Since whitetails carry more weight on their front hooves, these are slightly larger than those of the rear, and the hooves of bucks are larger than those of same-age does.
Some research indicates that buck hooves are slightly more rounded at the tip than those of does, perhaps because the extra weight carried by mature bucks causes additional wear.
Some also believe, although studies have never proven it, that drag marks appearing between tracks in snow less than 6 inches in depth indicate the passing of a buck. In snow deeper than 6 inches, however, it is impossible for deer not to leave drag marks, so their presence reveals little about age or sex.
The hoof itself is comprised of the outer, tough horn made of keratin (our fingernails are made of the same material) and a spongy surface on the sole that provides some shock absorption and traction.
Deer hooves wear constantly and, like our own nails, are replaced as they wear, although the rate of growth varies with the season.
Their narrow feet and legs are designed for speed and maneuverability. The rear legs provide the greatest thrust, while the front legs steer with great precision.
Unlike humans, the whitetail’s front shoulders lack a collarbone assembly and are free-floating — their front legs can pivot independently of each other, allowing for those “on the dime” turns at which we marvel.
A powerful rear leg structure allows whitetails to leap over tall obstructions, even from a standing start. From a dead stop, they can clear a fence or windfall of up to 7 feet; once running, that vertical height increases to over 8 feet.
Bundling all this together is a mass of muscle and a coat of dense, hollow hair — not fur. The white-tail’s coat is a shade of color that blends in well with many surroundings.
That the darkest hair is on the top, especially along the spine, is no accident. It gives the impression of a shadow cast from above. Grayish hairs scattered through the winter coat’s shoulders and haunches also tend to act as a shadow effect, as well as serving to blend into the trunks of trees.
White patches beneath the chin and along the entire underside help to break up the deer’s own natural shadow, making it look less than three dimensional to passing predators.
But beyond just camouflage, the whitetail’s coat is designed to protect. Since it must do so both in warm weather and extreme cold, whitetails evolved two specialized coats, and therefore must molt twice a year.
The spring molt occurs in May in the North, and as early as March in Texas, and is marked by the shedding of the long winter hair. Winter coats are usually fully grown-in by mating season.
Their winter coat, the one most hunters encounter, is comprised of darker, sun-absorbing guard hairs and a second layer of woolly underfur. Unlike the summer coat, the winter coat’s individual guard hairs are hollow, increasing the amount of dead air space and insulation. So little heat escapes that snow falling on a deer doesn’t melt.
Considering that whitetails have evolved a coat that — besides keeping them protected from the elements — is designed to “protect” them from predators through camouflage, one might wonder why they have such a conspicuous white tail for which they are named.
This “flag” serves an important purpose. Its evolution was no accident. Although deer survival depends largely upon being unseen in the forest, they are social animals that need to keep track of each other. Thus they evolved a tail that meets both needs.
When lowered, the tail presents only minimal white to the searching eyes of a predator, and so doesn’t adversely impact camouflage. Raised, however, it becomes a white beacon to other deer, serving as a warning that danger is present, allowing fleeing deer to easily follow each other.
Since the tail is raised only when danger is imminent, and only when the whitetail is exercising its speed and agility in an escape (which are its last, best defense), it is probably no disadvantage that predators can also see the flag. However, whitetails don’t always raise this flag when escaping. A deer that is trying to sneak away often pins its tail tightly to its rump.
The tail also serves as a silent early-warning system. When a whitetail is suspicious of a noise or object, it erects its rump hair and pumps its tail up and down. Since deer usually turn to face the possible threat, this silent warning is usually only viewed by other deer to its rear. Once the danger is identified and located, the tail becomes fully erect. Now every deer within eyesight is silently warned.
If the noise or intruder is eventually deemed to be non-threatening, the cautious whitetail will flick its tail side-to-side once, relax, and go on about its business. This flick lets other deer know that “the coast is clear.”
When you live life as food for something else, much of what you do is designed to avoid ending up on something else’s menu while you find something to put on yours. To that end, white-tailed deer have evolved remarkably acute senses.
The whitetail’s sense of smell may just be the most important when it comes to avoiding predators communicating with other deer.
Although studies have never quantified just how much better the whitetail’s sense of smell is than our own, there is unanimous agreement among scientists and hunters that it far outstrips our own meager scenting abilities. Not only can deer differentiate between species through just the use of scent (even the best of us would have a hard time scenting a wolf, but even if we did catch a whiff, would you know what it is you’re smelling?), they seem to be able to determine the age of an odor. In other words, wolf scent that is old, though it registers on the deer’s “smell-o-meter,” causes a far different behavioral reaction than one that is fresh.
When it comes to warning deer of danger, the sense of smell is the ultimate judge. Hearing a noise, the deer will look in that direction. Seeing what is making that noise may cause the deer to stare intently. But even when taken together, the deer still may not be able to identify the intruder or be inclined to flee.
One good whiff, however, is enough to finally pass judgment. And, of course, a deer needn’t see a human, wolf or cougar to know that it needs to disappear. Seeing a predator simply isn’t required when you can smell it.
Scent is also an important communication tool, especially for fawns and does trying to keep track of each other, as a means of finding a prospective mate, and for detecting invisible, chemical sign-posts that tell bucks about each other’s rank and territory. And as mentioned earlier, deer can scent-track each other, a useful tool in following other deer to safety or food.
Finally, like us, deer follow their noses to food. Whitetails do one thing that especially enhances their sense of smell. They wet their nose with their tongue so that scent molecules increase in dampness as they enter the nostrils. Molecules so humidified tend to cling better to olfactory cells.
It makes great evolutionary sense that an animal that lives in the woods, where the distance one can see is limited, would develop other means of interpreting signals. The sense of smell fills that role. But deer have at least one other tool that aides them when visibility is limited — an acute sense of hearing.
You and I have eyesight that perceives depth of field, or distance. Our hearing, however, does not, built as we are with immobile ears set on either side of our head. The whitetail’s ears sit atop the head, and can move independently of each other. It isn’t uncommon to see a deer with one of these large “audible scoops” facing one direction, with the other pointing off somewhere else. Whitetails may even keep one ear forward and another rearward while at full gallop, so that they might hear if they’re being pursued from behind, while they simultaneously listen for trouble ahead.
By being able to direct their ears, whitetails not only hear better than we do, they can determine the direction and distance from which a sound emanates. If it reaches the left ear first, then whatever made the sound is nearer to that side, and through comparing the minute difference in time it takes the sound to reach the other ear, deer can effectively triangulate to get a fix on the source.
While humans tend to turn toward a sound, deer may just turn an ear toward it. By doing so, they can amplify the noise. For gathering sound waves, whitetails have four times more ear surface area than do humans. In addition, they can hear sounds that we can’t, particularly at the higher frequencies. White-tailed deer can hear sounds in the 20 to 20,000 Hertz range; humans, from 500 to 12,000 Hz. The deer’s hearing isn’t supreme in the animal world, though. Dogs can hear better, being able to discern sounds in a range that begins lower (15 Hz) and ends higher (44,000 Hz).
Despite excellent hearing, sudden loud noises may confuse the whitetail’s ability to detect the source or direction of the sound. As some hunters can attest, deer sometimes stand around even after a loud gunshot, apparently unable to find the source. Most research indicates that deer move around less, or are more nervous, on windy days, most likely because they are uncomfortable with their diminished hearing.
The third major sense, vision, is the whitetail’s least acute. It isn’t that their eyesight is poor. It just isn’t quite as superb as are their hearing and scenting abilities.
White-tailed deer eyes are adapted to see well both in low light (even in darkness) as well as under the bright light of day. Their pupils contract into a narrow slit, unlike ours, which form a circular opening. This slit concentrates light in a narrow band against the back of the eye, or retina, which contains the light-sensing receptors clustered in a horizontal band. Combined with the actual placement in the skull, deer have a remarkable 270-degree field of view. The only place they can’t see is behind them. Our field of view is limited to 180 degrees.
Inside their eye, whitetails (and other animals designed to see in low light) have a membrane that you and I lack — the tapetum lucidum. It is this membrane that reflects the light of your car’s headlights. It also allows light to reflect through their eye’s light receptors twice, increasing their ability to see in the dark.
Do whitetails see color? That debate still rages. In order to see color as we know it, an animal must have the right kind of photoreceptors. Our eyes have two kinds — cones, which give us daylight and color vision, and rods, which enable vision in low light, but in shades of gray, like a black-and-white movie.
Deer definitely have rods, but studies conflict on whether or not they have cones. Two studies insist that there are cones on the whitetail’s retina, and seem to indicate that whitetails see some color, especially in the yellow and blue ranges. These studies also indicate that if deer do see color, they are least sensitive to long wavelengths — those in the red-orange range.
However, another study that used electron microscopes found that whitetails do not have color-sensing cones. Some studies also indicate that whitetails see well in the ultraviolet range, which is invisible to humans.
Whatever the case, deer are remarkably adept at seeing motion. The slightest movement by a hunter or other whitetail will focus the deer’s unwavering attention. Deer can stand unblinking for what seems like an eternity, trying to get you to move again.
Often they’ll lower their head for a second, trying to fool you into thinking that they are no longer observing you. Within seconds, however, they snap their head back up. If you’ve moved so much as an inch, they’ll note the difference and vanish in a flurry of bounds and snorts.
The whitetail’s array of senses is imposing. It is very difficult for any living thing to sneak up on them, although obviously this occurs or predators would have vanished long ago, and human hunters would have long since given up. And although we’ve discussed their senses separately, they work in concert.
A deer may hear a sound first, then turn to watch for movement. If it can’t see it, it may move downwind to see if it can catch a whiff. One or another of the senses will eventually determine whether or not the deer can remain safely, or warn it to move off.
Whitetails spend most of their lives in groups, a habit that improves their chances of survival. With many eyes and ears on alert, the deer can easily detect an approaching intruder. When one deer senses trouble, it quickly communicates alarm to other group members. Understanding how whitetails communicate can help you predict their behavior — upping your odds of taking a deer.
Sounds Made by Deer
Compared to other animals, white-tailed deer aren’t particularly vocal. That shouldn’t be surprising, since sound doesn’t carry well in the woods, and animals that are prey species are better off not advertising their presence by making a lot of noise.
That said, whitetails do make an array of sounds, all of which are designed to communicate with each other. Sounds are made by both sexes and at all ages.
Of course, females and fawns regularly communicate through a series of grunts, whines and bleats. Doe-fawn calls are seldom useful to hunters, although a fawn bleat or bawl can sometimes lure a doe into view.
Of most importance to hunters are the sounds deer make during the autumn mating season. Both bucks and does emit agonistic calls — sounds designed to imply aggressiveness. A single low grunt is used by both sexes year-round to let other deer know that they aren’t at all happy about sharing food, or that the other deer is too near or unwelcome.
As the encounter becomes more intense, the aggressor deer may add a series of snorts. This “grunt-snort” call is most fully developed in rutting bucks, particularly between mature bucks that are of near-equal stature physically and socially.
The most threatening sound a rutting, dominant buck can make is the “grunt-snort-wheeze” designed to let his rival know that he won’t tolerate his presence. If the competitor doesn’t respond to this call by leaving, a dominance battle may erupt.
Although not often heard by hunters, another whitetail call made during the autumn, especially during the rut, is the “tending grunt.” This low, guttural sound is emitted by a buck courting a doe in heat, or while he is tracking her.
Some hunters confuse this mating grunting with the whitetail’s alarm call. Often called a “buck snort” this wheezing whistle is actually made by both bucks and does. Caused by the sudden expelling of air through the nasal passage, it serves as a warning to all other deer nearby that danger lurks. When deer are suddenly startled, this sound is singular and explosive; when they have detected trouble from a distance, warning is often given in a series of lengthier snorts.
Sometimes just a barely perceptible movement of an ear is all a deer needs to communicate. Other times it’s just a twitch of a muscle — and danger is understood.
Deer in groups may stomp their feet when alarmed to warn others. But foot-stomping can be heard for only a short distance.
The most-used communication tool may be a deer’s tail. A casual side-to-side motion — wagging similar to that of horses or cattle — with no hair standing erect signals no danger. If the tail begins a sharp side-to-side motion with the tail horizontal or upright and hairs are erect, you know that the deer is sending out signals of mild alarm.
If nothing else confirms that feeling, the deer may go back to what it was doing and not take flight.
But once the deer is convinced the danger is real, it will hold the tail upright, waving it back and forth, exposing the white hair underneath. This signals a high state of alarm, and any deer within sight of it will quickly leave the area.
Other Silent Messages
Glands — those mysterious chemical-producing organs found in the oddest of locations — exert tremendous control over the seasonal routine of the whitetail.
Located primarily in, or just below, the skin, glands serve as generators of chemical communication for whitetails, enhancing the role of the deer’s already important sense of smell.
Each gland emits its own unique scent, known as a “pheromone.” Think of pheromones as the alphabet of an olfactory language, a language that allows deer to tell each other things about their readiness to mate, to recognize each other, to establish dominance or territory, and to warn others of impending danger. All of these important signals are transmitted without a sound, and are readable by passing deer long after the messenger has disappeared.
In a forest environment, where sound carries poorly and members of the species rarely congregate in large numbers, an eloquent language of odors seems like an immense advantage. It is.
The roles of some glands aren’t fully understood because they have only recently been discovered. However, we do know, or suspect, that the following glands function in certain ways”
• Found just in front of the eye, the preorbital gland is a hairless, shallow slit-like pocket. Witnessing a deer scent-mark a twig with this gland brings on an involuntary twinge in the human observer, for it almost appears that the deer is poking a stick into its eye.
Bucks frequently rub the preorbital gland on twigs that overhang buck scrapes. Researchers don’t know what message is conveyed by the scent emitted from this gland, but it certainly is of importance to whitetails, for passing whitetails definitely stop to check the odor left at these sites.
Not only do rutting bucks frequently use this gland on overhead twigs, they flare it during displays of dominance, as do does when they are nursing their fawns.
• Forehead glands are thought to be used for scent marking. During autumn, whitetails of both sexes rub their foreheads on branches, depositing this gland’s scent.
• Interdigital glands are found on all four feet in folds between the whitetail’s toes. Although the purpose of this scent-making gland is unknown, it must, at the very least, serve as a means of leaving a scent trail. Such a trail would alert deer to the passing of one of their kind, an important message year-round, but especially during breeding season.
• Located about 6 inches above the hoof, the metatarsal gland is marked by a white tuft of hair on the outside of both rear legs. Interestingly, this gland is far larger in northern subspecies of whitetails. In black-tailed deer this gland has been proven to emit an odor that warns other deer of danger. Studies have failed to confirm that the whitetail uses this gland for the same purpose.
• The tarsal gland is large and significant, located on the inside of the whitetail’s leg at the tarsal joint. It is marked by a raised tuft of long hairs. Like a large brush, this tuft becomes “painted” with the pheromones released from within, as well as with urine, which the deer deposits on this gland through a behavior called “rub urination” or “scent urination.”
In this technique, deer of both sexes hunch up slightly and urinate on the inside of their rear legs. As the breeding season progresses, the tarsal gland of mature bucks becomes stained from the frequent rub urination, and the odor of it is detectable even by humans. The tarsal gland is generally considered by hunters to be the most important of the “communication” glands.
Whitetail Hunting is an exquisitely photographed book that offers more insight into deer behavior than any book on the market. Each hardcover copy retails for $21.95, and can be ordered by visiting www.michaelfurtman.com or www.shawnperich.com.