By Mark Kenyon
“Antler growth, mineralization, and casting is largely controlled by hormones and regulated by photoperiod (the amount of light per day).”
– QDMA’s Whitetail Report 2011
In a nut shell, there it is. Deer lose their antlers every spring because of their changing hormones, specifically testosterone and that’s all there is to it. But the process of deer growing and eventually losing their antlers is a topic of endless fascination, so I thought today we’d dive into it a little bit further.
As was just mentioned, the growth and casting of antlers is due to testosterone, which is controlled by the amount of light received per day. Testosterone levels take off in July, peak in late October/early November and then begin a downward spiral into late winter/early spring. The rise towards peak testosterone levels results in the shedding of velvet and hardening of antlers during early September, and the eventual decline of these levels then signals the final drop of a buck’s head gear.
While testosterone is the main factor controlling antler drop, several other factors can have an impact on testosterone and accordingly have an impact on the timing of bucks shedding. First and probably most well known is the fact that high levels of stress on a buck can speed up the shedding process. This stress is frequently caused by harsh weather, poor nutrition, or injury. Dominant, mature bucks are also more apt to shed early, most likely because they are more active in the rut and can enter the late winter in a poorer physical condition.
Conversely several issues, of which I was surprised to hear, can lead to a late drop. One of these factors is the presence of estrus does late in year. For whatever reason, whether it be a late rut in the south or herds with highly skewed sex ratios, when estrus does are present late in the year, bucks testosterone levels tend to stay high, which usually leads to a later antler drop. It makes sense, but it’s something I never would have thought of! Also in the same line of thought, bucks that are involved in an extreme level of fighting can produce increased levels of testosterone, resulting in an unusually strong level of mineralization and a later loss of antlers.
I’m convinced that it’s human nature to be interested or even obsessed by antlers and every time I dive deeper into the science behind them, I walk away even more fascinated. Truly a wonder of the natural world, whitetails antlers will continue to captivate us for many years to come and with this new insight, my appreciation for them only continues to grow.
The majority of this information was gleaned from the 2011 Whitetail Report produced by the QDMA and you can access the full report online by following the link below.