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The Whitetail’s Glands & Scent Communication

March 29, 2009
By Tommy Kirkland
From a physical human aspect, we rely on eyesight and memory to distinguish other folks along with the spoken language. Yet for the white-tailed deer, their world of communication is quite different and is performed primarily through the work of glands and scent…



Scent pheromones are instinctively utilized by whitetails to convey a realm of communication related to dominant hierarchy and sexual interactions. They are crucial for other social interactions – particularly with females raising their offspring. These scents are produced by several different glands located on the animal’s body and serve deer of all ages and sex.

The most common glands by far are the tarsal glands, which are located inside the rear legs of a buck or doe. Tarsals are believed to be the prime calling card for whitetails to distinguish themselves – identifying one another. The scent released from the tarsals may enable whitetails to distinguish not only the sex of a particular deer, but the age as well.

During the pre-rut, 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 the front hooves, bucks will then perform what is known as “rub-urination”. Here a buck will bring the tarsal glands of both legs together and urinate upon the glands while simultaneously rubbing his rear legs and hindquarters – stimulating the tarsals and depositing scent upon the ground.

Though we may never fully understand this unique behavior, it is believed that “rub-urination” upon the tarsal glands allows deer to identify one another. Dominant bucks use tarsal rub-urination to pronounce their presence – particularly in the pre-rut. Whitetails of all classes – young, old, female, and male will periodically perform rub-urination on their tarsals throughout the year.

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 fat lipids are released during rub-urinations. These factors may contribute to the distinct smelly odor. Finally genetics and testosterone levels could also play a significant role in why one buck’s tarsals are darkened more so than another bucks.

The next set of glands in the whitetails’ arsenal of communication are the interdigital glands - located between the hooves of both the front and rear legs. The glands, like the tarsals, are also a major contributor to distributing scent for rutting bucks that paw the ground through scrape behaviors.

Being that each deer scent is 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 to establish their basic home ranges. This is crucial for herd socialization and for parenting females rearing young. These glands are believed to be the foremost way whitetails track one another.

In addition, another major gland for the whitetail are the forehead glands. 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 base.

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 may not actually contribute to pre-rut scraping behaviors. Although this gland may 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.

The whitetails’ salivary glands inside the mouth may help bucks spread scent at overhanging licking branches for scrape marking. Bucks after slamming the forehead glands and antlers into a rubbed tree will also periodically lick the shredded tree – utilizing the salivary glands to an unknown extent.

Recent studies into whitetails working overhanging licking branches at scrape sites are now beginning to conclude that the nasal gland – in the nasal passages of a deer’s nose contributes to scent communication as well as provide a lubricating moisture for the airway – particularly with cold dry air.

Other glands that deer have are the metatarsals on the outside of the hind legs – yet 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, particularly Dr. Karl Miller, think this gland may 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 work to instinctively determine if a doe is in estrus. Overall, the whitetails’ world of scent communication is complex; yet by learning the role of each gland, the sportsman will not only appreciate the creature hunted, but gains a better understanding when examining sign, traveling routes, and all the signpost activity left by whitetails as they traverse the land.



Fact Box

Whitetails of all classes – young, old, female, and male will periodically perform rub-urination on their tarsals throughout the year.

 
 

 

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