The horns of the Giraffidae are unlike those of any other mammal. They are present at birth as cartilaginous knobs, which rapidly ossify and grow slowly throughout life. They consist of a bony core that at first is separate from, but later fuses with, the skull. In Giraffa they arise over the anterior part of the parietal bones behind the eyes, the forward base growing over the frontoparietal suture. In Okapia they arise on the frontals above the orbit.
Horns occur in both sexes, but growth is less vigorous in the female.
Giraffa also bears a median horn on the forepart of the frontal bones and the back of the nasal bones that develops to a greater or lesser extent and is identical in its mode of growth with the posterior horns. The skull of Giraffa is characterized by large pneumatic sinuses above the nasal bones and cranium. These are developed to a much lesser extent in Okapia and do not extend back over the cranium. The low-crowned molars are characteristically rugose in giraffids, being unlike those of all other mammals, in which the enamel is always smooth. The upper molars lack inner accessory columns.