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Not Your Typical Antlers

By Jim Heffelfinger

Antlers were probably important to humans as tools ever since we learned to walk upright. Maybe human bipedalism actually developed so early hominids could walk around and gather shed antlers. Okay, that’s a stretch, but the archaeological record clearly shows antlers were very useful as awls, punches, arrowhead chippers, and other tools because of their useful shape, density, and hardness. Their frequent use in religious and ceremonial settings shows that they have captivated humans long before hunters wore scent-locking, perspiration-wicking, anti-UV, photo-silkscreened camouflage.

The diversity of sizes, textures, and shapes of antlers in nearly all members of the deer family give ample opportunity for wonder and amazement. No two sets of antlers are exactly alike, but each species has a basic shape that most individuals in a population resemble. I never tire at looking at any antlers, but when a set of antlers deviate from this typical pattern things get interesting. These abnormalities we call “nontypical” elicit a lot of interest and discussion about the causes and reasons for such deviations from what the buck intended to grow. Around many gas stations or sporting goods stores, one might hear discussions about kicker points, drop tines, cheaters, forks, crab claws, webbing or palmation, double brows, double drops, cactus bucks, and triple beams. Some affectionately refer to these nontypical growths or formations as “trash,” but that seems a little harsh for something so amazing. I recently heard someone use the term “goodies” (now that’s more like it). Despite the four by four purists, most people love the looks of a rack with a little character…or a lot of character. It is the oddities that capture our interest the most. If all bucks looked the same, they would be about as interesting as does.

Because of the persistent and widespread interest in nontypical antlers, there has been some research into the causes of abnormal antlers. From close observation and work with captive deer, we know some, but not all, of the many factors that can cause nontypical antlers. Genetics, age, nutrition, injury, parasites, disease, hormones, and magnetic/electronic forces all come into play. Let’s take a look at each one in turn and highlight what we do know about these factors.

Genetics

Many odd points and abnormalities are the result of the animal’s genotype, or genetic blueprint. Antler characteristics are inherited from the buck’s parents. A nontypical buck will frequently produce a disproportionate number of offspring with nontypical points. Also, females contribute half the genetic blueprint for antler qualities to their offspring. As a result, females that had nontypical fathers may consistently produce buck fawns that grow up to be nontypicals even when fathered by different bucks.

Genetically-programmed antler oddities can be seen year after year in an individual. A buck may have a small bump on the outside of his back forks at 2.5 years old, then a 2-inch kicker point in the same spot the next year and a 4-inch kicker on both rear forks at 4.5 years old. Palmated antlers that are “webbed” like a moose are a good example of a characteristic that is thought to be genetically inherited. Biologists in Utah even reported observing 14 mule deer bucks in the 1950s that had no antlers at all. They felt that this was a genetic abnormality because all bucks came from one localized area.

Age

We all know how age affects antler size; young bucks are still allocating nutrient resources to body growth and not antler development. It follows then that young bucks are not going to show many nontypical characteristics because that requires robust antler growth. Bucks rarely start expressing kicker points and drop tines before they are three years old. There can also be an interaction between age and genetics. This phenomenon is termed epigenetic effects whereby a gene is not expressed until later in life. In many cases, we may not be able to tell if a young buck has genetics for nontypical growth anymore than we can tell if a young boy has the genetics for a bald head.

Nutrition

In any given year, a buck only has enough energy for growing large antlers if he satisfies his own body maintenance requirements first. In poor years or on over-populated ranges, deer do not have the luxury of growing large racks because they barely have enough nutrients to maintain their body condition. Good nutrition maximizes antler growth, which means the buck can physically express his genetic traits. Regardless of the cause of the abnormality, good nutrition is necessary to provide the building materials.

Injury

Physical injury or trauma to either the velvet antlers or a major skeletal structure can result in nontypical antlers. Injury probably accounts for most of the very freakish heads. Any injury to the velvet antler may damage the cartilage-like structure of the growing antler and affect the blood flow and deposition of calcium and phosphates.

Nicks and cuts in the velvet antlers can produce points and odd formations. This has led some to suggest that the awe-inspiring double drop tine might be caused by bucks trying to slip through a fence and getting the underside of their beams caught (and nicked) on a fence strand. This is an interesting observation, but it appears that drop tines are mostly of a genetic origin. Bucks in velvet do a pretty good job of protecting their antlers because they are sensitive during that phase of the antler cycle.

There are reports of game keepers in early Europe who would jump-shoot red deer with bird shot when they were in velvet. The intent was not to kill the deer, but to pepper the growing antlers with lead pellets to cause nontypical points to proliferate.

Besides direct trauma to the growing antler, injuries to a large skeletal structure such as a broken leg bone often causes a misshapen rack the next antler cycle. If the front leg is injured, either side of the rack may be affected. However, if the rear leg is injured the opposite side of the rack is usually misshapen. Some have written this off to coincidence, however, there is a significant amount of evidence from several species of deer showing this contralateral (opposite-side) effect is real. Studies by Texas Parks & Wildlife Department in the late 1960s showed that amputation of a rear leg stunted the opposite side of the rack in all 6 experimental animals.

Injury to the pedicle (base) itself nearly always causes nontypicals. Extensive trauma to the pedicle before growth begins or soon after is the source for many very strange racks. Bucks with two mainbeams on one side are usually the result of this type of injury.

If one pedicle is injured severely, that side or both sides will be malformed during the next antler cycle. In addition, the nerves may “remember” the injury and reproduce nontypical antlers for several years. This “trophic memory” only occurs when the injury is substantial and occurs in the early stages of antler growth when there is a high density of nerve connections in the growing antler tissue. We can add this incredible phenomenon to our list of antler mysteries we don’t fully understand.

“Acorn points” are a common injury-based oddity seen each fall. This is a swelling in the middle or near the tip of a hardened antler tine. Acorn points are caused when the buck bumps the growing tip of the tine on something hard. The velvet on the tip is injured and, in the process of repairing itself, deposits more antler material at that location.

If an antler tine breaks completely while still in the velvet phase it may stay attached to the rack via the velvet skin and re-fuse with it leaving a pendulous (hanging) tine that usually has a large rounded tip.

Researchers working with sika, roe, fallow, and red deer, have also succeeded in making antlers grow out of abnormal places on the buck’s skull. By grafting cells from a buck’s pedicle (base) to another place on the frontal bone (forehead), researchers have been able to produce deer with a third antler growing out of their head between their eyes. All 3 antlers undergo the normal sequence of growth, velvet shedding, and casting (drop off). One experiment involved grafting pedicle cells on to the leg of a European roe buck. Incredibly, a small antler grew on the leg, lost its velvet and was later cast normally! Few people would argue that this buck would belong in the nontypical category of Boone & Crockett!

Trauma to the frontal bone of the skull can induce antler growth in not only bucks, but also in does. In 1894, W. Blasius reported that a female European roe deer grew a 4-inch antler after a piece of window glass was accidentally driven into her scalp. Injuries to a buck’s eye orbit will sometimes produce a third antler growing from the injured bone.

Hormones

The proper production of a variety of hormones is necessary to produce antlers. Seasonal fluctuations of male hormones (androgens) occur because the pituitary gland at the base of the brain detects changes in day length through the optic nerve. As the days get longer in the spring or shorter in the fall, the pituitary gland responds by regulating levels of some hormones differently.

After a full summer of growth, a substantial increase of testosterone, associated with the approach of rut, causes blood vessels in the velvet to dry up. Once dry, the velvet is stripped off in a short period of time.

The hardened antlers then remain firmly attached to the pedicles throughout rut until a post-rut drop in testosterone weakens their attachment and they fall free. The antler cycle is incredibly complicated and involves an intricate coordination between several androgens (not just testosterone) and compounds that act as an antler-growth stimulus regulated by the pituitary gland. Researchers have successfully produced 2 complete sets of antlers in one year by duplicating the day length sequence of two annual cycles in a 12-month period. They have also conditioned deer to grow antlers throughout the winter and shed them in the spring when most deer are just starting their annual development.

Young fawns that are castrated shortly after birth, do not develop pedicles because they never produce necessary testosterone required for this first step in antler development. A buck that is castrated while in velvet will never polish or shed his antlers because he lacks the necessary rise in testosterone to trigger the drying of the velvet. The buck then continues to grow more antler material in the next antler cycle, but never sheds its antlers until he finally carries a grotesque mass of velvet antlers. These bucks are sometimes referred to as “cactus bucks.” There are other more complex causes for a buck to stay in velvet perpetually. One such cause just now being investigated involves what may be plant compounds or environmental contaminants that chemically castrate the buck by interfering with the hormonal cycle.

Bucks that are castrated while in the hardened antler stage will drop their antlers within a few weeks because of the sharply falling testosterone level. Bucks castrated after they drop their hardened antlers, will grow new antlers the next year, but they will never be polished or shed because of the lack of sufficient hormone levels.

Tumors have been known to affect the hormonal environment and thereby produce antler abnormalities such as antlered does or cactus bucks. Viruses such as Epizootic Hemorrhagic Disease (EHD) can also cause hemorrhaging in the testicles or other effects that disrupt the proper production and circulation of male hormones that regulate antler growth.

Parasites and Disease

Besides disease-caused hormonal imbalances, various parasites and viruses can play a minor role in the occurrence of nontypical antlers by directly affecting the growing antlers. Epizootic Hemorrhagic Disease can result in incomplete hardening of the antler tips because of damage to the velvet’s blood vessels before antler growth is complete. The disease strikes deer in late July, early August which corresponds to the last stages of antler growth.

In elk, the brainworm (Elaeophora schneideri) clogs the carotid arteries that supply blood to the head and results in gnarly and malformed antlers. Ticks are common on velvet antlers, although in some cases, even blood sucking parasites can cause malformed antlers if they disturb the velvet and disrupt the flow of minerals to the growing antler.

Magnetic Fields, Electric Currents, and other Hocus Pocus

It has been observed that applying a strong magnetic field to developing antlers can produce bizarre antler shapes. This is more of an interesting side-light than anything of practical value to the casual deer enthusiast. The application of a constant, low-level DC current to the growing antler tips can drastically alter the shape and direction the antlers grow. Electric current generally reduces the length of the tines, but increases the number of odd and abnormal points.

There are many possible causes of antlers growing in strange and wonderful ways, but injuries and genetics account for a vast majority of those observed in the field. Oddities and freaks are normally not tolerated by nature; natural selection quickly removes them from the gene pool. However, an enormous nontypical freak is certainly not at a disadvantage when it comes to battling for dominance. Early in the antler growing season when dominance hierarchies are worked out, other members of the buck bachelor groups would probably give a large, crazy-antlered buck wide berth. The process of natural selection has worked remarkably well throughout evolution in weeding out the “trash.” But, when I see a big gnarly buck in the field with lots of “goodies” all over his antlers, I’m glad for the exceptions.

Jim Heffelfinger is a Certified Wildlife Biologist who has worked as a biologist for the federal government, state wildlife agencies, universities, and in the private sector in Wisconsin, North Dakota, Mississippi, Texas, New Mexico, and Arizona. Jim has authored or coauthored more than 100 magazine articles, scientific papers, and book chapters in national and regional publications. He has also written TV scripts for the Mule Deer, Coues Whitetail, and Pronghorn episodes of “Leupold’s Big Game Profiles” which are now airing on the Outdoor Channel. He is an adjunct professor at the University of Arizona, Professional Member of the Boone & Crockett Club, and currently works as Regional Game Specialist for the Arizona Game and Fish Department.

For more information on antler growth, genetics, hybrids, and other fascinating topics, order an autographed copy of Jim’s new book “Deer of the Southwest” from www.deernut.com.

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