Antlers: The Process from Start to Finish

The young hunter had a grinning smile as he handed me the antlers from the buck he harvested with his bow. The antlers were covered in velvet with a couple of odd tines. The time of 60 days had passed, so it was ready to be officially scored for the Pope and Young record book.

As I started measuring this great trophy, the young man’s questions started coming: “What causes the nontypical points? What makes the antlers grow so fast? When does the velvet fall off? What makes deer shed their antlers?” and many others.

On pondering his questions, I thought the best way to answer them would be by explaining to him (and those of you reading this article) what antlers are made of, and how they grow from start to finish.

The Start

Antlers are one of the most sought-after materials for hunters and outdoorsmen. Tagging a buck with a large set of antlers or finding sheds in the offseason is a treat for any of us who pursue these elusive critters.

These antlers are very fascinating and are one of the fastest-growing materials known to man. Deer antlers, which are actually bones that exist outside the body, can grow up to a quarter-inch per day, and up to one inch per day on large elk and caribou. They start as a fuzzy, velvet-skin growth, grow very rapidly, lose the velvet, become hard antlers, and in a few months, they fall off! And next year, it happens all over again!

So, let’s look at the process.

In my part of the country, most fawns are born primarily in early to mid-June. A few months after a buck fawn’s birth, his antlers start to develop due to increasing testosterone — growing from the tips, outside-in, developing a soft, fuzzy outer skin coating that we call velvet. This velvet is very vascular, coursing with blood cells that carry nutrients to the antlers. This is coupled with nerve endings that energize rapid growth of the cartilage that, as the season progresses, is slowly replaced by bone material. Antlers take approximately 100 days to complete their growth.

During this time of year, deer are starting to graze/browse heavily to put the weight back on that they lost over the prior winter. Bucks especially need large quantities of nutrition to build not only their body weight, but to grow their headgear.

Calcium and phosphorus are the main nutrients that are required to develop and grow antlers. These nutrients are needed in such great quantities, that grazing and browsing alone cannot supply it.

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Researchers have found that due to the great need of these nutrients, calcium is taken from other bones in a buck’s body to supplement the antler growth. The calcium is taken from non-weight-bearing bones such as ribs and shoulder blades, causing the buck to go into an osteoporotic state — a weakening of the bones due to loss of calcium. The deer family is one of the only animals known to go through this process, and these bones are replenished to a normal state as the season progresses.

These nutritional needs are not only important during the spring and summer, but also after the rut. If a buck can replenish and store the nutrition he lost during the breeding season to build back body weight, it will greatly contribute to good spring antler development.

As the summer progresses, bucks will continue to put on weight and grow antler material at a very fast rate. During this period of antler growth, their testosterone levels are very low; however, as fall approaches, these testosterone levels (and other nutrient levels) increase, causing rapid final mineralization and thus hardening of the antlers to bone.

We normally see this transition in late August and early September. Here in North Dakota, we are fortunate to have an early archery season that affords hunters the opportunity to kill a buck in velvet. These velvet bucks can look like giants and are very impressive, due to the velvet giving their antlers a thick, heavy appearance.

As the testosterone increases, the velvet begins to lose vascularity, which causes it to dry out and rubbed off — typically within 24 to 48 hours. I’ve personally seen a buck in full velvet walk into a brushy, treed area, only to re-enter the field minutes later completely clean of his velvet. Crazy, right?

I was fortunate to take a buck in Montana that was in the mid-stage of rubbing off his velvet. This buck was in a grassy, rolling hills area with few trees. I shot him after stalking within 30 yards. Apparently, the grassy terrain was not conducive to him quickly removing his velvet.

Just a note, bucks do not rub off their velvet due to an “itch” or “irritation.” When the rubbing occurs, the velvet is dried and dead, therefore it has no nerve endings or feeling. This activity is suggested to come from the photoperiod shortening, thus triggering the first stages of rubbing and marking areas.

Hard Antlers

Now that the antlers are hard bone, bucks will continue to build their bodies in anticipation of the rut. Their testosterone levels will continue to increase, as they establish hierarchy and dominance in preparation for fights with any potential breeding competitors.

Fluctuations in testosterone levels throughout the year are regulated by the changes in the amount of daylight (photoperiod). These testosterone levels typically peak in early through mid-November, bringing a frenzy of rutting activity to the landscape. The trigger of the rut is not weather-related, but rather light-related. Weather may determine the time of day that most rutting activity occurs; however, it only influences the timing of this rut activity to a minimal degree.

The Finish

As December rolls upon us, the rutting activity decreases, and by mid-December, a buck’s testosterone levels start to drop rapidly. This triggers cells to re-absorb the bone at the pedicle, causing the antlers to fall off.

Mature bucks normally shed their antlers earlier than younger bucks. Antler shedding may also be dependent on nutritional conditions. Non-stressed, healthy bucks are known to carry their antlers later into the winter. Or, as we have seen recently, bucks impacted by EHD may hold their antlers all season because of incomplete testosterone changes.

After these antlers have dropped to the forest/prairie floor, the remaining pedicles become “scabbed over,” rather than “healed over,” and the process of growing antlers is finished…until it all starts again.

Deer, elk, and caribou are the only known animals to continuously regrow bone tissue, and the tissue between the pedicle (living) and antler (dead) is the only known connection between living and dead tissue in mammals.

Nontypical/Deformed Antlers

When speaking about deformed or true nontypical antlers, I feel there is a difference — even though they are the same on a measuring/scoring basis. Deformed antlers are from an injury/disease, whereas nontypical points can be from age or genetics, and often have matches on both antlers.

Deformed/nontypical antlers can be caused by genetics, age, injuries, and remnants of diseases such as EHD.

Genetics from both the buck and the doe he bred will contribute to nontypical antlers. Studies show that does will carry their father’s traits. A doe that is an offspring of a nontypical buck will birth a larger portion of nontypical bucks — even though she was bred by a typical buck — thus passing on her father’s antler genetics. Researchers have also shown that deer with a greater diverse gene pool, meaning more breeding bucks in an area, contribute to more points on a yearling buck’s headgear.

As a buck ages, he may tend to develop nontypical antler characteristics more prominently than in his younger years. This may reflect his genetic traits as he grows older.

We have recognized that if a buck injures an antler during the growing season, the nerve-endings may become damaged, and a nontypical point may grow at that location. In many known cases, because of the damaged nerves, a nontypical point will grow in the same location the following year, which is attributed to “genetic memory.” This may answer the question of why a young buck has a nontypical point or a deformed point.

If during this growing period, a buck injures a rear leg, it can have a direct correlation of a deformed antler — usually on the opposite side of the injured leg. A front-leg injury will have a correlation of a deformed antler that is usually on the same side as the injured leg.

It is not known why this happens or the actual cause. Some speculations suggest a possible balance-stabilization correction, or maybe a right-brain/left-brain correlation. Either way, pay attention to the deer that you and others kill, and you will most likely find this to be true.

EHD has created questions in recent years about antler growth, and if it is a contributor to odd antler formations. This is a viral disease caused by biting midges that create a fever, weakness, edema, and internal bleeding. Deer can survive EHD; however, side effects from the fever and high internal body temps may cause atrophy of a buck’s testicles and inhibit testosterone development.

Due to this lack of testosterone, bucks may not shed their velvet, or their antlers. In years during an EHD outbreak, I’ve witnessed several bucks still in velvet well into November and December. EHD will also cause antlers to be very brittle and can break off when trying to drag or move a buck.

Residual effects of EHD can also impact the shedding of antlers. A buck may not lose his antlers due to low testosterone. Subsequently, during the next growing season, antler material may grow around the base of the still-attached antler — forming the “cactus” look.

Other antler oddities may be seen as well. One year, following an EHD breakout, I photographed a couple of bucks that grew what appeared to be sacks of blood that hung down by each antler. The anticipation was these sacks would harden into a “club.” But as the summer progressed, the sacks dried up and fell off. According to a biologist, this was likely due to inadequate testosterone development.

This is not an entire list of what may cause deformed or nontypical antlers, but it gives us a good idea what to look for as we go afield this hunting season.

As we can see, these magnificent animals we pursue every year are much more fascinating than just the crown of antlers they carry. They are real marvels of nature, performing natural processes unknown to any other species.

Once summer fades, we will be heading to our favorite deer-hunting spots or exploring new ones. The antlers will be complete, and the velvet will be rubbed off. We’ll see bucks move from alfalfa fields to grasses to herbs to forbs, in preparation of their annual rutting rituals.

If you are fortunate enough to put a tag on a buck’s antlers in the coming years, please take a little time to reflect and be thankful for the opportunity.

The author has been an outdoor writer throughout his hunting career, and is an Official Measurer for Pope and Young, Longhunter’s Society (muzzleloader), and the North Dakota Big Game Record Book. He has been bowhunting for over 40 years and lives in Mandan, ND, with his wife, Judy.