Whitetail Tips

Why Bucks Make Rubs

WHY DO BUCKS MAKE RUBS?
by
Peter Fiduccia "The Deer Doctor

Let’s take an in depth look about why and what a rub actually represents to deer. Finding a rub certainly alerts one to the fact that a buck or bucks are present in the area. Rubs can also help a hunter determine the travel routes a buck is taking to and from bedding and feeding areas.

Some say that a buck rubs his antlers to remove the velvet. Frankly, that is a misnomer. Rubs are
not primarily made to remove the velvet. Over my 45 years of videotaping, observing and hunting whitetails, I have discovered what most seasoned hunting veterans and biologists know, and that is, most velvet falls off a buck’s antlers by itself. Most times the velvet hangs off the antlers and is annoying or disturbs a buck’s view. So, he rubs it off as quickly as possible on any available shrub or tree.

But these are minor points when it comes to understanding the significant importance that rubs represent to deer and to hunters. Being as well-versed about all aspects of rubs and what they really mean to deer will not only make you a better deer hunter, it will improve your hunting success ten-fold. In a deer’s world a rub is a very important social
“sign post” to both the local herd and, equally important, to transient bucks. Rubs of the season are used by ALL bucks that come in contact with them to express their individuality, social status (where they rate on the pecking order ladder), age class, current rutting condition and much more. This is true of both bucks and does. Female deer will often visit rubs to leave their calling cards as well. I will discuss more about this later.
 

An individual buck uses a wide variety of visual signs, aural signs, and pheromone odors at a rub site to express his status and individuality to other deer. The pheromones he deposits on a rub come from a wide variety of glands and organs including scent from his saliva, urine, feces, an organ in the roof of his mouth, his penal sheath, preorbital gland and more. Other deer smelling the rub will detect all they need to know about him and especially where he ranks in the male pecking order.
  

Between the time the velvet is removed until the onset of the rut, a buck actually does very little rubbing. Once a buck’s adrenalin begins to kick in, however, and the rut isn’t far off, he begins to rub his antlers in earnest – not to primarily strengthen this neck muscles, but rather to leave a visual and olfactory sign post to all other deer.

While it was once believed that rubs are made by all age classes of bucks – it is now known that a majority of rubs seen in the woods are made by bucks 2.5 years old and older. But be aware that nothing about behavior in the world of whitetails is written in stone. That means not every rub you find was made by a 2.5 year old buck or by a more mature buck--but the odds are good that most rubs are made by bucks 2.5 years old or older.

A buck spotting a newly made rub is naturally drawn to it in order to discover who made it and to leave his scents on the rub as well. It is an instinctive behavioral trait.

When a buck makes a rub, he does so by purposefully acting out several behavioral mannerisms. First, he approaches the intended tree and stops several yards away and urinates. The urine flows over his tarsal glands and mixes with the odor emitting from them as it falls to the ground. When he finishes urinating, the buck squats slightly and squeezes his rump muscles causing pressure on his pre-pucial gland (which is an exocrine gland located within the penal sheath) which then emits a fluid unique to that buck.

Next, he approaches the tree and before doing any rubbing at all – he sniffs the tree several times and then licks the area repeatedly. By doing so, he deposits scent from his salivary glands located inside his mouth . These glands contain enzymes to help in digestion. The enzymes in the saliva also contribute to the scent left on the tree the buck is about to rub. The same glands are used when a buck makes a scrapes and deposits salivary gland scent on overhanging branches and licking sticks. 

By licking the tree the buck not only deposits scent from his salivary glands but also from a diamond-shaped organ in the roof of his mouth called the vomeronasal organ. This organ
serves some of the same purposes as the nose. It is used primarily to take in estrus odors and
precisely evaluate the status of a doe via the odor from her urine. The buck does this by making a lip curl, or Flehmen gesture. The buck will curl its upper lip and suck air into its mouth so that the odor it is sniffing makes contact with the vomeronasal organ. Analysis of urine through the vomeronasal organ may help to synchronize the breeding readiness between bucks and does, and ensure that both sexes are in peak breeding condition at the same time.

Then a buck rubs his forehead skin hard against the tree several times. Again, he does this to deposit scent from his forehead glands (which are located in front and behind the antlers). These glands get considerably larger and emit more secretions during the rut. The more mature a buck is and the higher he ranks within the social status the more glandular secretions he will produce.

The forehead glands secrete an oily substance which darkens the area on the frontal lobe portion between the antlers--which is darker and more noticeable on mature bucks. The purpose of the forehead gland is two-fold. Some biologists feel it is mostly used for marking purposes when making rubs on trees. The oily secretion from the forehead glands contain a particular olfactory genetic calling card that indicates social status and hierarchy amongst the other bucks and does. Typically, a buck higher in the pecking order will make rubs with more frequency to announce his presence and stature. The forehead gland is just another gland a buck uses to leave his individual scent on a rub or overhanging branch at a scrape.

As you can see by now, a rub is “alive” with a variety of pheromone odors left by each gland. But a buck is not finished leaving glandular pheromone scent markings on a rub – not yet. Finally, he will actively rub with his preorbital, or
lachrymal, glands that are tear ducts located in the front of the deer’s eyes. These are sebaceous and sudoriferous glands located at the rim of the preorbital. The sebaceous glands produce a fatty substance called sebum that lubricate the area and keeps it from drying out. The sudoriferous glands produce scent or pheromone.

I have seen countless bucks rub trees, brush, branches and other vegetation while angling their heads in order to make sure their preorbital gland made contact with what they were rubbing. I can only assume that they did this with purpose in order to leave a pheromone at the spot they rubbed with their preorbital gland. I have noticed this on numerous occasions when seeing a buck make a rub. I have also seen it when a buck makes a scrape and then carefully rubs, licks, chews, and passes his preorbital glands on an overhanging branch.

So there you have it – the real facts about what a rub actually represents in the world of the whitetail. It is most definitely a visual and scent-laden sign post to communicate a variety of messages to other bucks and does.  

That is why it is worth the time to make a mock rub. It is a significant strategy that when made correctly, will attract both bucks and does (mostly bucks) through their instinctive behaviors. Once a passing deer sees and smells a rub that has an odor that is not its own – it is naturally drawn to it. Remember that the scents you use on the mock rub must be used sparingly. If you use too much scent, it will smell unnatural and either make the buck act cautiously as he approaches or even turn him away from it and walk off.