Dan Gausman, age 13, of St. Paul, Minnesota for his question:
How do horns differ from antlers?
People who believe in devils insist that the wretches have hooved feet and wear horns on their heads. It's odd that they should be scared, because all the animals of this sort are strict vegetarians. Most, though not all, animals who wear horns or antlers are gentle creatures and certainly none of them ever devoured a human being.
Cattle and sheep, goats and most antelopes wear permanent horns on their heads. The deer wear branching antlers and most of them shed their handsome crowns every year. Both the horned and antlered animals are herbivores who graze or browze on vegetable food. Most of them are shy and more gentle than the meat eating carnivores. Most of them use their spiky weapons only against rivals, though the one horned rhino and the two horned domestic bull can definitely be hostile to humans.
The rhino's horn is made from outer skin fused with parallel fibers of material called keratin. The horns of cattle grow from the epidermis, the outer skin layer, and contain an assortment of different keratins. These durable protein cells are related to human hair and nails. Various keratins also are used to build the beaks and claws of birds, tortoise shells and lizard scales, hoofs and whalebone.
A horned animal sprouts two bony growths from his skull early in life. The sheaths of horn material have bony bases. They are permanent attachments and may continue to grow throughout life.
The antlers of a deer are made entirely of calcarous bony material and usually they are shed every year. In late fall, the pronged antlers of a handsome elk may be five feet long and weigh as much as 70 pounds. In mid winter, he sheds his branching crown and for a few weeks the proud stag has no antlers.
Early in the new year, two bony bumps appear on his forehead. These are his new antlers. As they grow, they are covered with velvety hair and nourished by the blood vessels in fleshy layers of skin. During this period, the stag is said to be in velvet, for his growing antlers are sheathed in soft flesh and short furry hair.
The fleshy coverings also contain nerves and the growing antlers are sensitive until they reach their full size. Then their velvety gloves dry up and peel away. The stag is ready to battle rivals who try to steal females from his family. The new bony antlers are used as weapons. The winner gets to keep and protect the herd.
Among the cattle, both cows and bulls wear permanent horns made of durable protein materials. Both the male and female reindeer wear bony antlers, but this is unusual. Among the other deer, antlers are worn only by the male and he grows a new set each year.
A young male deer sprouts only a couple of single spikes during his first year. A new prong is added each year as he grows older. Come fall, the adult stag loses his antlers a little sooner than the youngsters do. For a few weeks he cannot maintain discipline. The young rascals take advantage of this and prod him with their little spikes. Tut tut!