Humans rely on eyesight and memory to distinguish other folks, but a whitetail’s world of communication is performed primarily through the work of glands and scents.
Scent pheromones and their distinct odors are instinctively utilized by whitetails to convey a realm of communication related to dominant hierarchy and sexual interactions.
They are crucial for other social relations — particularly with females raising their offspring. These scents are produced by several different glands, and serve deer of all ages and both sexes.
The most-common glands, by far, are the tarsal glands located inside the rear legs of a buck or doe. Tarsals are believed to be the prime calling cards for whitetails to distinguish themselves and identify one another.
The scent released from the tarsals might enable whitetails to distinguish not only the sex of a particular deer but the age, as well.
During the prerut, bucks really begin to put their tarsal glands to work — especially at scrape sites. After working the classic overhanging licking branch and pawing the ground with their front hooves, bucks will perform what is known as rub-urination. Here, a buck will bring the tarsal glands of both legs together and urinate on them while simultaneously rubbing its rear legs and hindquarters, stimulating the tarsals and depositing scent on the ground.
Though we might never fully understand this unique behavior, it is believed that rub-urination allows bucks to establish dominance. Mature bucks use tarsal rub-urination to pronounce their presence, and do so more often than younger bucks.
Whitetails of all classes — young, old, female and male — will periodically perform rub-urination on their tarsals throughout the year. Yet this activity really kicks in with the prerut.
Observations afield strongly indicate that the most-assertive and aggressive bucks are usually pungent, with a strong tarsal odor produced by the tarsal rub-urination process, and have some of the darkest-stained glands.
One reason for this smelly distinction is that these dominant bucks are constantly working the tarsals.
Biologically, when bucks perform rub-urination, there is a composition with bacteria and the urine, and it is believed that lipids are released during rub-urinations. These factors might contribute to the distinct odor.
Finally, genetics and testosterone levels could also play a significant role in why one buck’s tarsals are darkened more than another’s.
The next glands in the whitetails’ arsenal of communication are the interdigital glands, located between the hooves of the front and rear legs.
These glands, like the tarsals, are also major contributors to distributing scent for rutting bucks that paw the ground to make scrapes.
Being that each deer scent could be individually distinguished, scent released from the interdigital glands helps deer to follow or locate one another — especially rutting bucks in pursuit of females.
These glands allow whitetails to form scent travel routes, helping them establish their basic home ranges. This is crucial for herd socialization and for does rearing young. These glands are believed to be the foremost way whitetails track one another.
In addition, another major gland for the whitetail is the forehead gland. Like the interdigital glands, these glands serve rutting bucks, depositing scent through tree rubs and the marking of overhanging branches.
The scent from the forehead glands of dominant bucks is vital for the mating process, and is believed by some biologists to trigger females into heat. The forehead glands are actually seated between a buck’s eyes and antler bases.
The next gland on the whitetails’ palette is the pre-orbital gland. Located near the eye pit toward the nose, the pre-orbital is controversial and might not actually contribute to prerut scraping behaviors.
Although this gland might be used on an overhanging branch during a buck’s scrape, most experts believe the gland serves other purposes related to buck aggression, and is most likely a tear duct. There is still a lot about this gland we just don’t know.
The whitetails’ salivary glands do not produce scent, but it is theorized that when bucks lick overhanging branches or tree rubs, some type of communication is being received or reinforced. The behavior is similar to when bucks periodically lick their tarsals glands.
However, whether salivary glands contribute to scent communication is really unknown.
Studies in recent years into whitetails working overhanging licking branches at scrape sites have indicated that the nasal gland might contribute to scent communication, as well as provide lubricating moisture for the airway, particularly with cold dry air. These glands do help in locating other deer, and are vital for scent messaging.
Other areas of note are the metatarsals on the outside of the hind legs, but they are not really glands. Their purpose remains a mystery, but some biologists believe they are used with aggression and could be related to the instinct of flight with what is called exteroceptive sensory — picking up on external stimulus sources, possibly allowing deer to detect vibrations.
This is purely speculative in relation to this poorly understood “gland” that is more of a duct than a gland.
All male deer possess a preputial gland that is internal to a buck’s penal sheath. Its primary function is lubrication for this genital area.
Biologists from the University of Georgia, namely Karl Miller, think this gland might produce pheromones contributing to a buck’s rutting odor.
All these glands are vital for whitetails to survive, yet deer also use their other physical attributes in combination with scent communication. Simply, the nose and eyes work to pinpoint scrape sites and previously rubbed trees, while organs like the vomeronasal — through lip curling — work to instinctively determine if a doe is in estrus.
Overall, the whitetails’ world of scent communication is complex, but by learning the role of each gland the sportsman will not only appreciate the creature hunted but gain a better understanding when examining sign, traveling routes and all the signpost activity left by whitetails.