Cervids are the only mammals habing antlers.
Antlers are bony outgrowths of the frontal bones of male deer.
The caribou and its domestic counterpart, the reindeer, are exceptions, in that the females have smaller antlers. The Chinese water deer has no antlers at all. Mechanical breakdown of plant fiber is facilitated by chewing the cud. This specialized form of digestion is known as rumination. They have well developed hindquarters and are built for leaping, they also have a distinctive hunched posture.