True horns, though, are found only on cows, sheep, goats, and some of their relatives. Horns are made of bone covered by specialized hair follicles that make a substance similar to human fingernails. (See: "Special Investigation: Inside the Deadly Rhino Horn Trade.")
Antlers, on the other hand, are solid bone—an extension of the animal's skull—and are mainly found on males in the deer family. (Watch "Amazing Antlers.")
But lots of other animals sport headgear that mimics horns or antlers, too. These bumps, spears, and protrusions all serve a purpose for the animals who wear them; some brandish their "horns" to intimidate rivals, while others flaunt them to attract a mate.
Enjoy this gallery of animals with horns that would make a unicorn green with envy.
Tales of the Jersey Devil stalking the Pine Barrens have scared residents for centuries, but the winged monster's origins may lie in the region's religious disputes of the 1600s.
Menopause is rare among animals. Why do orcas go through it?
Studying fin scrapes in a closed group of orcas shows that postmenopausal mothers put energy into helping their sons, but not daughters or grandchildren.
