關於長頸鹿頭上的觸角

觸角 (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 giraffids have true ossicones (as opposed to horns or antlers). The base that a deer's antlers grow from is very similar to ossicones.Ossicones are similar to the horns of antelopes and cattle, save that they are derived from ossified cartilage, and that the ossicones remain covered in skin and fur, rather than horn. Antlers (such as on deer) are derived from bone tissue: when mature, the skin and fur covering of the antlers, termed "velvet," is sloughed and scraped off to expose the bone of the antlers.

Their appearance is a reliable method of identifying the sex of a giraffe : the horns of females display tufts of hair on top, whereas those of males are larger and tend to be bald on top.

2012-01-25 22:29:00 補充：
And also to control the blood pressure on it's neck when the giraffe lower it