Horns are hard, bony structures that protrude from the heads of certain animals, primarily found in species like cattle, sheep, and goats. They are made of a core of bone covered by a sheath of keratin, the same material found in human nails and hair. Horns can serve various purposes, including defense against predators, competition for mates, and social signaling within species. Unlike antlers, which are shed and regrown annually, horns are permanent and continue to grow throughout an animal's life. They come in various shapes and sizes, depending on the species, and can be used in various cultural practices, such as in traditional ceremonies or as tools.