White-tailed deer are the largest wild mammal in Illinois. They are browsing herbivores that roam the woods, sometimes entering yards and fields.
The nurturing females are called does. The young babies, called fawns, have bodies covered in spots to camouflage themselves. Those spots mimic drops of sunlight dancing through the leaves. The males, called bucks, are the only mammal living in Illinois that grows antlers.
Antlers vs. horns
Antlers are bones with a branching-out shape. Antlers are shed and regrown annually. Horns are never branched, and they are permanent. In some species, like bison, the horns never stop growing. Antlers and horns usually only grow on the male of the species, but that is not always the case. For example, female reindeer, also known as caribou, also grow antlers.
Antlers are the fastest growing bone material known. In just 120 days a mature buck can grow more than 200 inches of antler! Let’s follow this remarkable cycle of the white-tailed buck.
As antlers grow, they are covered in velvet. This fuzzy, soft outer layer not only protects the bone as it is growing, but it is covered in blood vessels that supply the antlers with all the nutrients they need to grow. During this growth period, the antlers are spongy. Antlers have a main beam and tines, or points, that grow off them.
A young buck, or yearling, will venture out on his own after about a year and a half. A yearling will have small antlers with few tines. Each year, as long as the buck has proper nutrition, his antlers will grow more tines until he is about 6 years old. Then the tines will just grow a little heavier. Antlers will start to decline if the buck is lucky enough to reach old age, which is 8 or 9 years old.
By August, a buck’s antlers are fully developed and have hardened into solid bone. The velvet dries up and starts to fall off. The buck is now ready to start sending messages. He will leave signals to mark his territory and attract a mate.
One signal is called a rub. A buck will scratch his antlers across small trees or shrubs, shredding the bark. They may also chew or lick some vegetation. Glands in their forehead will leave a scent on these rubs.
Another signal is called a scrape. These are made with their feet, not their antlers. The buck will paw at the earth, leaving a bare patch about 1 foot to 3 feet in diameter. He will urinate over his scrape and also leave a rub nearby.
Flight and flaunt
Bucks hang out in small bachelor groups until it is almost time to mate. Then they separate and become enemies. They will grunt loudly and fight each other to see who is dominant. Sometimes antlers get locked together and the bucks push one another. Or they may repeatedly separate and crash antlers into each other. The rattling sound of the antlers will attract other males to the scene. One buck will emerge the champion, and he will strut his stuff.
Words to know
Bachelor: Juvenile male animals that are still immature.
Gland: An organ that secretes chemical substances.
Herbivore: An animal that feeds on plants.
The time that bucks and does mate is called rutting season, or the rut. In Illinois, the rut usually peaks in mid-November. Most of the year, deer are active at dusk and night. During the rut they are actively searching for mates all day long. A receptive female will urinate on the scrape if she likes the buck. Then he will track her scent. Several does may mate with the same dominant buck.
Shed, then repeat
When rutting season is over, bucks no longer need their antlers. Bucks most often shed their antlers between the end of February through March. It is the growth of new antlers in their heads that literally pushes the old antlers out of the way, just like our adult teeth push up the baby teeth’s roots and loosen them. Then the cycle begins again with the velvety growth period.
Finding a shed antler can be a treat! But remember to leave it where you found it. In the forest preserves, it is illegal to collect anything. Plus, antlers are a favorite snack for mice, providing them with calcium and other important minerals. And it isn’t nice to take someone else’s food.
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