By Tracie Hornung

This is the time of year when reindeer antlers might bring to mind those silly fabric antlers humans wear to holiday parties or attach to their dog’s heads. (Why they think a dog might enjoy this, I can’t answer.)

Caribou, also known as reindeer. Courtesy U.S. Fish & Wildlife Service

But some facts show that real reindeer antlers are pretty amazing.

But before we discuss antlers, let’s get our terminology cleared up. Reindeer and caribou are essentially the same. Here in the Western Hemisphere  they’re commonly known as caribou; in Europe, reindeer. But even though we’re in the West, in light of the holiday season, let’s refer to them as reindeer.

Reindeer are members of the family Cervidae, including deer, elk and moose, and they are widely distributed across the Arctic and Subarctic. A small, endangered population in northern Idaho and northeastern Washington is the southernmost group in North America.

Reindeer are the only cervid in which the females also have antlers. And male reindeer have the largest antlers relative to body size among deer. In some subspecies the bull reindeers’ antlers are the second largest of any deer, after the moose, and can range up to 39 inches in width and 53 inches in length.

Antlers grow from bony supporting structures called pedicels. Secretions from the pituitary gland initiate the growth of antlers, and growth is rapid — up to almost an inch per day.  As they grow, they’re covered with skin and soft hair called velvet, which carries blood vessels and nerves.

As antlers reach the end of their growth, the centers become filled with coarse, spongy bone and marrow spaces. The velvet dies and wears off, helped along by the reindeer’s rubbing and thrashing its antlers against trees and other vegetation.

In winter, hormone stimulation to the male reindeer’s antlers wanes as daylight shortens.  (Female reindeer don’t lose their antlers until calving time; spring or summer.) Without hormone stimulation the pedicel loses calcium, weakening the point of connection between it and the antler, and eventually the antler breaks off.

But Mother Nature sees to it that nothing goes to waste: Fallen antlers are eaten by rodents and other animals — a rich source of calcium and minerals for them.

For the difference between antlers and horns see the University of Michigan’s Animal Diversity Web site.

Here’s a unique way to save reindeer lives:
Glowing reindeer antlers deter car wrecks