Musk deer can refer to any one, or all seven, of the species that make up Moschus, the only extant genus of the family Moschidae. Musk deer are more primitive than cervids, or true deer, because they lack antlers and facial glands, and possess only a single pair of teats, a gall bladder, a caudal gland, a pair of tusk-like teeth and—of particular economic importance to humans—a musk gland.