November 04, 2010
Finding a shed antler is always special.
My daughters and I make shed hunting a family experience.
Although my two little girls still have no clue that all of the antlers they've "found" were actually artificially placed, the well-spent time in the woods is a way to introduce them to hunting. Recently, when I asked if they liked looking for Easter eggs or antler sheds better, both agreed that finding shed antlers was cooler.
Without a doubt, each and every antler you find is a unique treasure that brings wonderment and speculation, such as: Is the buck still alive? Is he 21⁄2 or 31⁄2 years old? Does he still hang out in these woods? Will he be the dominant buck next year? Questions like these are exciting, but exactly what do you know about antlers and the shedding process?
Just like my daughters, primitive man gave respect and reverence to the antlers and deer he hunted. Bowhunter Magazine Conservation Editor Dr. Dave Samuel explains it best in his book, Know Hunting. "The best hunters would breed more; they (and their families) would eat more protein and hence survive better. In other words, the best hunters, and the hunters who killed the biggest animals (i.e., trophy hunters), would survive and would evolve."
Antihunters (and even some hunters) claim too many hunters focus only on trophy animals (big antlers). They argue that hunters kill off all the best animals and, by taking out all the top-end bucks, are reducing the genetic vigor of the herd. Let me make this point perfectly clear: Within all the biological studies on whitetail breeding dynamics and genetics, no proof exists to support this assertion.
A common question hunters ask is, "What causes an antler to drop?" Deer researcher John Ozoga found that providing bucks supplemental feed will delay their antler drop by more than a month from late December to mid-February. In fact, providing supplemental feed caused some bucks to carry their antlers into March. Ozoga concluded that nutrition and dominance rank within the herd most likely determine the time a buck will drop his antlers.
Research also has shown that bucks can cast their antlers earlier than normal if they suffer inadequate nutrition entering or following the rut, as well as in a prolonged rut.
Dr. Harry Jacobson at Mississippi State University (MSU) determined the majority of bucks will drop both of their antlers within days of each other, and many times, within days of the same date from year to year. He documented the annual antler drop of 24 bucks in his pen. On average, these bucks varied 4.4 days in annual casting dates, with one buck being 17 days apart. Some believe bucks possess an individual antler cycle that is centered on each buck's birth date.
Another MSU study showed that yearling spike bucks dropped their antlers sooner than yearling forked-antlered bucks. The primary reason for this was probably because the spikes were more nutritionally stressed and thus, shed earlier. This study also showed no relationship between antler mass and time of shedding, which is contrary to other studies that showed that as bucks grow older and gain antler mass, they shed their headgear earlier. Many biologists believe this occurs because many older, dominant bucks use a high amount of energy just to maintain a high dominance rank, especially during the rut.
Although antler shedding may seem pretty cut-and-dry in relation to nutrition, the effects of latitude seem to vary the results of antler shedding. For example, northern deer generally have a shorter and more intense rut. Biologists know the farther north a deer lives from the equator, the narrower the window of antler growth and rut. Because of this compressed timeframe, dominant bucks in the North generally drop their antlers before lower-ranking bucks. The exact cause of this is not fully understood, but most likely results from a rise in testosterone followed by a rapid decline due to a constricted rut. From a survival viewpoint, this makes sense, because bucks in harsh environments must cease all rutting activity if they intend to make it through the winter.
Contrary to northern deer, dominant deer in the South seem to shed their antlers later than subordinate bucks. University of Georgia deer researchers believe the longer and less intense rut, plus the more temperate climate, allows many southern bucks to be in better physical condition than some of their northern cousins. This advantage allows dominant southern bucks to sustain higher levels of testosterone over lower-ranking bucks, thus helping maintain their rank in the male hierarchy by keeping their racks.
The exact physiological cue of antler shedding in deer is complex. In short, decreasing day length signals the testes to lower the levels of testosterone which, in turn, causes the antlers to shed. Antlers are shed when a thin layer of tissue called the abscission layer disconnects the antler from the pedicle. This absorption of bone-to-bone between antler and pedicle is the fastest deterioration of living tissue in the animal kingdom.
Wildlife biologist Kip Adams from the Quality Deer Management Association (www.qdma.com) states, "The final color an antler becomes partly deals with the total time it took the buck to shed his velvet. If the velvet took a long time to shed, the existing blood most likely stained the antler and made it darker. Conversely, if a buck quickly sheds his velvet, the antler would be lighter in color." Most likely, the amount of moisture in the air, combined with oxidation during velvet shedding, determines the antler's final color.
Others believe if a buck lives in an open environment, his
antlers will be more bleached -- due to the sun -- than a buck that lives in a thick swamp or pine plantation. Still others believe an antler's color is a product of genetics or the species of tree a buck is rubbing. What-ever the actual reason for an antler's color, Adams points out, "Even within the same environment, you'll always have light, medium, and dark antlers."
Antlers are actually secondary male sexual characteristics, and the fastest-growing bone in the world. If you're regularly finding bucks that drop their antlers early, chances are the area is nutritionally stressed and needs some help. But remember, early casting by dominant bucks in the North is more common than in the South.
Although many variables such as nutritional and social stress, age, disease, and parasites can affect antler drop, many times it is a bodily injury. More often than not, rear leg injuries cause a deformed antler on the opposite side of the injury, whereas front leg injuries can produce a malformed antler on either side.
Sometimes a deer's antlers may not be shed and remain in velvet. This is generally the case with hermaphrodites (does with
antlers). This condition is caused by excessive testosterone or the absence of ovaries. One study showed that 1 in 20,000 does grow antlers. With bucks, dysfunctional testes with no testosterone can cause permanent velvet.
Whenever I give a deer seminar, it always amazes me how many hunters get the following question incorrect: "Which antler characteristic always increases throughout the life of a buck: the number of points, inside spread, or antler beam circumference (ABC), measured one inch above the burr?" If you said ABC, you are correct. Even during a nutritionally deprived year, when the number of points or inside spread can be severely compromised, the antler base must form over the previous year's pedicle, thus increasing in size or circumference. In fact, research has proven that next to a deer's teeth, the ABC is the best indicator of its age. Therefore, finding sheds and measuring the ABC can give you valuable information on the age structure of your bucks.