What is distinctive about each of the following: horns of bovids, antlers of the deer family, and horns of rhinos? Describe the growth cycle of antlers. What is velvet? Why is it called velvet?
Horns of Bovids- hollow sheeths of keratinized epidermis with a bone core; not shed or branched and grow continuously, found in both sexes.
Antlers- they are branched an composed of solid bone when fully mature, grow in the Spring where they develop beneath velvet. Only males have antlers except in Caraibou. They shed them after breeding season.
Rhino Horns- Hair-like keratinized filaments that arise from dermal papillae, cemented together but unattached to the skull.
Velvet is covering of highly vascular soft skin, called velvet because it is soft.
Horns of Bovids are attached to the skull. During annual spring growth, antlers develop beneath their velvet, When growth of antlers is complete just before the fall breeding season, blood vessels constrict and a stag removes the velvet by rubbing its antlers against trees. Antlers are shed after the breeding season. New buds appear a few months later to herald the next set of antlers. For several years each new set of antlers is larger and more elaborate than the previous set.