The Sloth is a slow-moving mammal that lives in the trees of tropical forests of South and Central America. There are three-toed sloths, among which is the ai, and the two-toed sloths, among which is the unau. Sloths are usually about 16 to 29 inches long. The flat, short head has big eyes, a snub nose, and primitive ears. The body is covered with short, grayish-brown hair. The tail is small in three-toed sloths and absent or vestigial in two-toed sloths.