Wordology, Ossicone

Ossicones are the nubs that stick out on the heads of Giraffes and male Okapi. They remain covered in skin and fur and are never shed, unlike other antlers and horns. Ossicones consist of cartilage that has turned to bone. In a young animal, ossicones are porous, with clusters of bony tissue interrupted by blood vessels and folded skin. As the animal ages its ossicones grow denser and more compact.

Both male and female giraffes have a pair of these hair-covered horns, but males use these to roughhouse with each other as they are growing up. As males mature, other calcium deposits can form near these horns, making it appear they have up to five horns.