The shape and surface topography of the scales change with wear. The coloration of the scales is dark brown, dark olive brown, pale olive, yellow brown, or yellowish. The hairs of the scaleless areas are whitish, pale brown to russet, or blackish, and the skin is grayish with a bluish or pinkish tinge in some areas. Three or four hairs are present at the base of each scale in the Asiatic species, but there are no hairs at the base of the scales in the African species. The scaly covering somewhat resembles a pine or fir cone.
Males are usually larger than females.
The head is small and pointed, and the small eyes are protected by heavy, thick eyelids. The oblong or cone-shaped skull is smooth. The lower jaw is a simple bladelike bone. There are no teeth. In the African species the pinna of the ear is not present, whereas in the Asiatic species the projecting part of the ear, or at least a thickened ridge, is present.