Ossicones are
horn-like (or
antler-like) protuberances on the heads of
giraffes, male
okapis, and their extinct relatives, such as
Sivatherium, and the
climacoceratids, such as
Climacoceras. Only giraffes and okapis have true ossicones (as opposed to horns or antlers). The base that a deer's antlers grow from is very similar to an ossicone.