Antler Growth

Posted on July 19, 2016

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“Antlers are an extravagance of nature rivaled only by such other biological

luxuries as flowers, butterfly wings, and peacock tails. The antlers of deer

are so improbable that if they had not evolved in the first place, they would

never have been conceived even in the wildest fantasies of the most

                  imaginative biologists.”         –         Richard Goss

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The imagination of most huntsmen is often besieged by fanciful thoughts of multi-branched, deeply pal-mated, coarse and widely spread antlers. In fact, we are all quite fascinated with this hardened bone. We plot, scheme and scout vigorously in an attempt to boldly rob a fine stag of his regal accouterments. The annual cycle of antler growth, hardening, velvet peel, casting and regrowth is a phenomenon unequaled in all of nature. Scientists and doctors have long marveled at the incredible rate of growth (1/4 inch per day), and the time involved in the full development of these appendages (approx. 100 days) regardless of their size. In order for us to fully appreciate the finished product of the magnificent, shiny ornaments adorning the male whitetail head, we should have an understanding of the unique process involved in growing such captivating features.

The Pedicle

 

This is where it begins: before a deer can successfully grow antlers he must first develop pedicles. Pedicle development occurs during the first four-to-six months of a buck fawn’s life. As the juvenile’s testicles mature, a sufficient amount of testosterone is produced to prompt pedicle enlargement. During the spring prior to his first birthday, a buck will start to grow his first real antlers. With each subsequent year, the pedicles continue to enlarge, facilitating a bigger antler base, which in turn promotes the possibility of larger antlers.

 

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Once a buck casts or sheds his antlers during the winter months the pedicle immediately begins to scab over. The swollen ring around the pedicle heals inward towards the center and forms a shiny surface. The timing of this process is relevant to the amount of stress incurred by individual bucks leading up to when it occurs. (I believe that under ideal conditions, a buck is genetically predisposed to cast his antlers annually within the same time period. I am currently involved in a research project to substantiate this belief.)

 

Regeneration

 

On or about March 20th, mature bucks in the Northeast begin growing new antlers. This coincides with the vernal equinox, a time when daylight once again increases. As is the case with most whitetail events, light, or photoperiodism, initiates changes. According to noted wildlife biologist John Ozoga,

 

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The seasonal secretion of hormones responsible for antler growth is controlled by the pineal gland, a pea-sized organ located deep within the mid-portion of the brain. The major pineal hormone is considered to be melatonin, which suppresses the production of luteinizing hormone by the pituitary gland. High levels of luteinizing hormone suppress production of testosterone by the testes. Changes in light signals received through the eye send electrical messages to the pineal gland, thereby controlling melatonin production and, indirectly, testosterone production. As nights get longer, melatonin production increases. Hence, the pineal gland plays an important role in translating seasonal changes in day length into physiological and developmental events. The male sex hormone testosterone is the primary hormone that controls antler growth, but numerous other hormones are also involved.

The first six weeks of antler growth is relatively slow, but development accelerates at a dramatic pace once the calendar turns to the month of May. Most of a buck’s antler growth is accomplished during the months of June & July, calcifying or hardening by mid-August.

Growth of antlers occurs at the tip and as they elongate a covering known as velvet encases them. This covering contains sensory nerves on the outside, which serves to minimize antler damage during the growing stage while inside, blood vessels supply all the necessary nutrients to the developing tissue. Because of the large blood supply required, the surface temperature of growing antlers is quite warm to the touch.

 

Nutrition

 

It is often said by dietitians, “you are what you eat”. No other phrase could more adequately depict the end result of maximum realized antler growth for bucks. Despite an individual buck’s genetic disposition, without proper nutrition in sufficient quantity, his antlers will never grow to reach their maximum potential.

 

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Antlers are made of protein as they grow in velvet, but solid mineral replaces the protein later. Obviously, because antlers are nothing more than regenerated bone, dietary concerns necessary for skeletal growth would also be a factor to antlers as well. Antler growth places a great nutritional strain on the animal. According to Robert Brown, head of the Department of Wildlife at Texas A&M, “During antler mineralization, most of the calcium and phosphorus in the antlers comes from the other bones of the skeleton, not directly from the diet.” It has been suggested that the same nutrient requirements necessary for growing antlers would equal that of a nursing doe with fawns.

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What is known about the specific minerals required in a buck’s diet that facilitates optimum antler growth is speculative at best. What we do know is that the earlier spring green-up begins and deer migrate from their winter yards, the sooner they can begin replenishing lost body-weight. It must be understood, when rations are in short supply, body growth will always take precedence over antler growth.  Although temperature and rainfall have no affect on the antler cycle, a damp spring promotes lush forage, which accelerates weight increase while simultaneously enhancing antler development. Bucks have the instinctive ability to choose certain food sources that are both palatable and preferable to them providing all of the digestible energy needed for antler growth.

 

Conclusion

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 Like leaves that suddenly burst forth each spring upon naked limbs of trees, antlers, in similar fashion, will also once again emerge. Although little thought is given to the process necessary to produce them, when fully grown and polished, these forms of annual growth and development fascinate us. Perhaps now, when the next opportunity arises to gaze upon a magnificent buck bedecked in his royal autumn attire, our fixation will hold a greater sense of appreciation for the crown adorning his mantle.

 

All images and text on this site are copyright protected and the property of R.G. Bernier

© 2016 R.G. Bernier Nature Photography – All rights reserved.

 

 

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Posted in: Whitetail Deer