Pangolins have large keratin scales covering their skin and are the only mammals with this adaptation. They are found in tropical regions of Africa and Asia. Pangolins are nocturnal animals, and use their well-developed sense of smell to find insects. Pangolins spend most of the daytime sleeping, curled up into a ball. Pangolins were classified with various other orders, for example Xenarthra, which includes the ordinary anteaters, sloths, and the similar-looking armadillos.
The physical appearance of pangolins is marked by large, hardened, plate-like scales. The scales, which are soft on newborn pangolins but harden as the animal matures, are made of keratin, the same material of which human fingernails and tetrapod claws are made. The scales are razor-sharp, providing extra defence. Pangolins can also emit a noxious smelling acid from glands near the anus. (Wiki.)