Facts About Antler Growth

Deer hunters are always fascinated by antlers, but what amazes me most is how some bucks can grow such large racks in a single summer.  Antler tissue is the fastest normal growing tissue known to man.  Considering that most antlers begin developing in late March and early April in most parts of the country and are finished growing by mid-August, that means that a 170-inch Boone & Crockett whitetail will grow more than an inch of bone every day.

During April, the first month of antler growth, the antlers grow very little, usually only a few inches.  In May the days continue to lengthen and antler growth accelerates, with most of that growth occurring during June and July.  Which means that at this time of year, you can practically watch a rack growing larger before your eyes!

How does antler growth happen?

Pedicles are the two circular areas on a buck’s skull.  The pedicles begin developing on buck fawns while still in the womb.  The pedicles finish developing after the buck fawn is born.  These pedicles serve as foundations for that buck’s future antlers.

Recently I read an interesting fact regarding pedicles.  In the Whitetail Report 2010, published by the Quality Deer Management Association, it’s stated that “transplanting material from a buck’s pedicle to other skeletal regions results in growth of antler tissue in the transplanted area.”  Translation:  If you transplanted a piece of pedicle onto a mouse’s forehead, that mouse would soon start growing an antler.  Kind of a neat idea, I think.

Antlers begin growing as a result of lengthening days, or photoperiodism.  Longer days increase the whitetail’s urge to feed, thus promoting growth.  As antlers begin to emerge from the whitetail’s pedicles, they’re covered with velvet, which is a hairy skin containing a network of blood vessels.  The blood vessels nourish the growing bone.  The blood in the velvet is what makes antlers appear dark brown, if not black, in summer.

How much or how fast antlers grow is dependent on two things, age and nutrition.  Obviously, a mature buck 3 ½ years old living in prime habitat will experience accelerated antler growth.  However, that same 3 ½ year old buck in poor habitat will grow a much smaller set of antlers.  Genetics also play a role, of course, but I’ve always believed (and many researchers agree) that genetics are the smallest part of the equation, simply because most areas of the country already have good genetics. 

It’s important to remember that antler growth is a secondary concern.  Throughout spring and summer, most of the food consumed by whitetails will contribute to their physical development.  Only after a deer’s physical needs are met will the surplus nutrients benefit antler growth.  And only after a whitetail reaches full maturity and all of its nutritional needs are met will those existing genetics shine through.

Just as curious as what triggers antler growth is what makes that growth stop. 

In late July or early August, bucks receive a natural boost in their testosterone levels.  It’s nature’s way of alerting them to the coming fall breeding season.  This spike in testosterone levels results in less blood flow to the antlers, which means that the antlers gradually stop growing.  Typically antlers stop growing approximately 30 days before the velvet is actually shed.  During these 30 days, bucks use minerals from their skeleton to harden their antlers.

Exactly when antlers stop growing is unknown, but it’s believed to occur no later than the second week of August, and typically around the end of July.  In other words, chances are good that the bucks you see now will be about the same size come archery season.  Once again, photoperiodism is the key factor. 

In spring, longer days and more sunlight spur whitetails to shed their winter coats and begin the growing process.  In fall, shorter days and less sunlight cause whitetails to shed their summer coats – and velvet.  In late August, many bucks begin shedding their velvet.  By mid-September, almost all of the bucks will have done likewise.

It’s also common for bucks to eat the nutrient-rich velvet after it’s off their antlers.  The whole shedding process, even for bucks with large antlers, usually lasts only a few minutes.