Antlers vs. Horns: What's the Difference?

The words "horn" and "antler" are sometimes used interchangeably for species that sport decorative headgear. However, horns are not just antlers on a different animal, or vice versa. While there are certainly similarities between the two, horns and antlers have distinct differences, from how they look to which animal sports them to when they grow.

Learn what distinguishes horns from antlers and which species have each.

What Are Antlers?

A common mistake people make is assuming deer have horns. But along with moose and elk, deer are members of the Cervidae family, the only class of mammals to grow antlers. With the exception of caribou or reindeer, only males grow antlers, and they primarily use them to compete with other males during mating season.

Antlers are grown every spring and shed every winter. It takes a lot of energy to grow antlers. Investing this energy while staying healthy enough to compete shows females that this is a male with great genes.

Cervids have pedicels, bony structures that support the antlers as they grow. In the spring, testicular and pituitary hormones get the growing process started. Antlers are covered with velvet, a kind of skin tissue that carries blood and nutrients to the antlers during development.

According to Animal Diversity Web, the spongy outer bone is gradually replaced by compact bone as the antlers stop growing. When the antlers are done growing, the velvet dies. The animal sheds this layer by scraping its antlers on brush and trees—an action that also stains, shines, and sharpens the rack. This final result looks really impressive to competing males and females.

In winter, when the growth hormones quit pumping, the pedicel loses calcium, which weakens the connection between the pedicel and the antler. At that point, off come the antlers.

What Are Horns?

Horns are found on members of the Bovidae family, which includes cows, sheep, goats, water buffalo, antelopes, and gazelles. Horns can appear on both males and females depending on the species, and the size and shape of horns vary wildly from one animal to the next.

Unlike antlers, horns are never branched nor shed. In many species, they never stop growing throughout an animal's life. The only scenario in which a bovid loses its horns is if they are broken off. The continuous growth of their horns is useful because they become worn with use.

Horns have a bony core that is covered with a sheath of keratin, the same stuff that makes up our hair and fingernails. The bony core of a horn is not exactly part of the skull but rather fused to the skull with connective tissue.

Similar to how cervids use their antlers, bovid males use horns in fights and displays of strength during breeding season. In species where females also sport horns, they're usually smaller and built more as a defensive tool than an offensive weapon.

Antlers and Horns as Trophies

The majestic antlers of an arctic caribou and the curling horns of wild sheep are prized trophies to game hunters. Within the animal rights argument is a concern about trophy hunting targeting younger males; they develop large horns or antlers before the age when the headgear can facilitate successful mating.

While proponents of hunting cite overpopulation and a lack of natural predators for certain species such as deer and bighorn sheep, killing these younger, stronger males can have negative consequences for the future of wild populations.