I was driving to New Glasgow on the weekend when a deer ran across the highway near Mount William. It was a young buck and he was sporting a small set of antlers which were covered with velvet. While many people refer to antlers as horns they are actually two different materials. Antlers, which are grown by animals such as deer, moose and caribou, have a very interesting biology. Antlers are actually bone, while horn is a form of skin, something like our fingernails.
Most horns, such as those found on cattle, have an inner core of bone covered by horn and are not shed every year. They also continue to grow as long as the animal lives. While both males and females of horned species of animals grow horns, in antlered animals only the males normally grow antlers. The exception is caribou, where both sexes grow antlers, and the occasional whitetail doe which may grow a set of antlers. The growth of antlers takes place over a short period from late March to the end of August. During their growth antlers begin as small bumps on the head covered with skin which is fed by many blood vessels. This skin is covered with very fine short hair which looks like velvet, hence the name.
The antlers grow very rapidly but declining day length late in the summer will trigger the blood supply to the velvet to shut off and the bone begins to harden. At this time the bucks rub their antlers against small trees to remove the velvet and, if you spend some time in the woods in September, you will usually find trees with the bark removed and strings of velvet hanging off them. Antlers serve an important function during the breeding season as male deer, moose and caribou use their antlers to fight other males for breeding rights.
Since the males with the largest antlers are usually those in the best condition they normally win any contests for females and will pass on their genes to future generations. Antler size is more a factor of nutrition rather than age. Male whitetail deer usually grow only a single spike or forked antlers their first year. The size will increase in following years but will begin to decline as the animal ages and its condition declines.
Male deer and moose will keep their antlers until late December when declining testosterone levels cause the antlers to drop off. Hunting for shed antlers is a popular pastime in the spring but finding them is a challenge as they donÔÇÖt last long. Squirrels, mice, porcupines and other animals seek out shed antlers for their calcium and other minerals.
Antlers are one of the fastest growing animal tissues, especially when you consider that a bull moose can grow a rack of antlers almost six feet wide in a few months, only to lose them and grown another set the next year. Researchers are interested in how this happens and how it possibly could be applied to human organs.
Don MacLean is an outdoor writer and biologist who lives in Pictou County.