Decoding Scent-Post Rubs
September 22, 2010
Scent-post rubs serve as communication centers for a lot of deer. During the fall, every mature buck in the area will visit an active scent-post rub at one time or another.
Oftentimes you'll find a "community scrape" located close to a scent-post rub. Some biologists believe that the scent deposited by bucks comes primarily from secretions in their forehead glands. They also believe this gland secretion is the source of the dark streaks on their foreheads. I'm no scientist (a Tennessee hillbilly could never even be a first cousin to a biologist or a scientist); however, I'm not sure about how much the forehead glands have to do with the scent on rubs and the darkening on a buck's forehead.
My family used to do taxidermy work, and I've caped out my share of bucks over the years. However, I've never cut into a pocket on a buck's head that contained anything, liquid or otherwise, that was dark brown or black. It would take a very dark liquid to account for the dark stains on a mature buck's forehead.
SCENT AND THE BREEDING RITUAL
Forehead glands may very well be a reality, but I personally believe that the dark streaks on a buck's forehead and the scent that bucks deposit on their rubs come primarily from the tarsal glands on their hind legs. You don't have to watch mature bucks for long before you see them rubbing their heads on their tarsal glands. This action transfers the same scent to a deer's forehead that is deposited in scrapes when a buck rub-urinates.
Usually the most dominant buck has the darkest forehead. This makes sense to me because the tarsal glands on mature bucks become more active during the breeding season, as these bucks frequently urinate over them into scrapes. The hair around the tarsal glands also becomes darker and darker as this process takes place. And it is no small coincidence that does close to or actually in estrus have the same response when they interact with a scrape as they do when they come in contact with a scent-post rub.
When a deer interacts with a scent-post rub, it will not only rub its forehead on the tree, it will also smell and lick the spot. The bottom line is this: Wherever the scent that is placed on scent-post rubs comes from, it definitely has a purpose in the breeding ritual of white-tailed deer.
RELATED: Understanding Different Types of Whitetail Rubs
Biologists have long believed that scent-communication rubs suppress the breeding urge of younger bucks. This makes sense. Of course, a fresh scent-post rub with the rank smell of a dominant old buck would suppress the breeding urge of a younger buck! That youngster would quickly realize that a mature buck was in the area, and he would be afraid to chase any local does. If a 1 1/2- or 2 1/2-year-old buck showed any aggression whatsoever toward the older, dominant buck in the area, it could be detrimental to his health, if not fatal. On the other hand, if no mature or older-age-class bucks were in the area making scent-post rubs and scrapes, a younger buck would try to do quite a bit of the breeding.
DOES AND SCENT-POST RUBS
It has long been believed by many whitetail experts that the presence of scent-post rubs can help speed up a doe's estrous cycle. I believe this to be true. When a doe close to reaching her cycle interacts with a scent-post rub or scrape, it may cause her to come into full estrus a little sooner than normal. This became evident to me by something my hunting partner, the late Lanny Mauldin, witnessed back in the '90s when we were hunting together on public ground in southern Illinois.
While we were scouting, we came across a very significant rub on a pine tree. The rub was larger than my calf and the bark had been rubbed smooth. The ground around the rub and the rub itself showed recent use. I advised Lanny to set up near that rub, and he did.
Later on, when we met at noon after the first morning's hunt, he had something very interesting to tell me.
The rub had been visited by several deer. The first two were 1 1/2-year-old bucks that showed quite a bit of interest. They spent a lot of time rubbing their heads on the rub.
They also licked it several times before they wandered off.
Around midmorning, two does showed up. Apparently they were either in estrus or very close to coming into it. The does' interaction with and reaction to the rub were spectacular. Both licked the tree and rubbed their foreheads on it. However, one of the does must have been much further along in her estrous cycle than the other.
According to Lanny, she would smell and lick the rub. Then she would make a high-pitched noise that he described as a squeal. She worked herself into a frenzy as she smelled and licked the rub.
"She jumped up in the air and danced around on her hind feet," Lanny told me. "She also ran around in circles each time she licked the rub. At one point, she backed her rear end up to the tree and rubbed her genital area all over it."
As Lanny watched, the two does hung around for 45 minutes, carrying on the entire time.
There is no doubt in my mind that this scent-communication rub helped speed up that one doe's estrous cycle and increased her desire to breed.
USING SCENT-POST RUBS TO YOUR ADVANTAGE
Most of the time a scent-post rub can be distinguished from a common rub because its surface will be slick or smooth from constant use. When bucks start rubbing their forehead on saplings or small trees for communication purposes, they eventually rub the rough surface right off of those trees.
Scent-post rubs are usually 4 inches in diameter or larger. They are frequently found on trees with aromatic properties such as cedars or pines -- sometimes even telephone poles or railroad-tie fence posts. I believe the creosote in the poles is an attraction to bucks.
Often these rubs will have a scrape develop nearby. A lot of the scent-post rubs that I've studied were made on trees with distinct bows in them, and bucks will always rub on the inside of those bends.
During your scouting trips, be on the lookout for scent-post rubs. I believe they are just as productive to hunt over as active scrapes because they serve basically the same purpose.
If none exist in your hunting area, there may not be a mature buck around. Many times these rubs are not associated with trails or travel corridors. Therefore, they can be difficult to find. There seems to be no rhyme or reason why they are located in the spots they are in.
"Breeding scrapes" will be made where the buck believes they are most productive.
However, I believe the availability of just the right tree has more to do with the location of a scent-post rub than with the locations of scrapes and other buck sign.
Do not let the lack of trails or other visual sign discourage you from hunting close to a scent-post rub. Bucks will many times approach these types of rubs from all directions, and a distinguishable trail may or may not develop. Do keep in mind that some scent-post rubs can become stale and unused. So make sure the rub shows signs of frequent and recent use before you decide to hunt over it.
I know it is common advice not to hunt right on top of a rub or scrape. Most writers will advise you to hunt on the trail leading to this type of buck sign. However, since a rutting buck might approach a scent-post rub from any direction, I feel that you should set up within shooting distance of the rub. Do not hunt a scent-post rub if the wind is wrong for it. Make sure your scent is blowing into the area that is most void of deer movement before you enter your stand. Move in and set up quickly on a scent-post rub that has been freshly worked. You never know how long the buck will stay in the area.
Just about any time you read an article about rubs, that article will invariably have something in it about "boundary rubs." Do rubs mark the boundary of a buck's territory?
In a way, they absolutely do because a buck will not rub outside the boundaries of the area he is living in at the time. Therefore, velvet-shedding rubs, mock-combat rubs and scent-communication rubs do mark a buck's boundary in a sense.
However, I think it is quite silly to use the term "boundary rub." In my opinion, bucks do not make rubs to intentionally mark any distinct boundaries. They simply make rubs inside their core living areas for the three reasons we have already discussed: 1) to announce their presence to other deer in the community; 2) to intimidate other younger or less dominant bucks; and 3) to attract receptive does.
Some writers like to talk about another type of rub that they refer to as a "visual rub." Are rubs easily seen in the woods and does this visibility aid bucks in finding them? You bet!
With the exception of a deer's flag, there are not many items that are brighter in the woods. Do bucks rub trees for visual purposes or is it just an added bonus because rubbing removes the bark and reveals the light wood underneath? I believe the answer is the latter.
In fact, I think that all of the various types of rubs we have discussed in this two-part series are visual. Certainly bucks use the high visibility of rubs to their advantage. I've seen places where a buck has crossed an open field and rubbed saplings in the woods on the other side as soon as he enters the trail. Will he use this visual clue to help him go straight across the field and into the woods on this trail? Yes, he will. Did he make this rub specifically for that purpose? I doubt it. However, I can say that I have sometimes used this situation to my advantage, and you probably have, too.
On occasion, I've cut down a rubbed sapling and rubbed another one a few yards away at a more desirable location closer to my tree stand. Several times this has worked for me like a charm. Yes, almost all rubs definitely are visual, but I don't consider the term "visual rub" to be a separate classification of rubs.
Studying rubs and using them to your advantage while hunting big bucks can be an exciting proposition. I hope this series has enlightened you and given you some food for thought about this interesting but complicated topic.