Sloths are mammals classified in the families Megalonychidae (two-toed sloths) and Bradypodidae (three-toed sloths), including six extant species. They are named after the capital sin of sloth because they seem slow and lazy at first glance; however, their usual idleness is due to metabolic adaptations for conserving energy. Aside from their surprising speed during emergency flights from predators, other notable traits of sloths include their strong body and their ability to host symbiotic algae on their furs.Sloths make good habitats for other organisms, and a single sloth may be home to moths, beetles, cockroaches, fungi, ciliates, and algae.Sloths are classified as folivores, as the bulk of their diets consist of buds, tender shoots, and leaves, mainly of Cecropia trees. Some two-toed sloths have been documented as eating insects, small reptiles, and birds as a small supplement to their diets. Linnaeus’s two-toed sloth has recently been documented eating human faeces from open latrines.Sloth fur exhibits specialized functions: the outer hairs grow in a direction opposite from that of other mammals. In most mammals, hairs grow toward the extremities, but because sloths spend so much time with their legs above their bodies, their hairs grow away from the extremities to provide protection from the elements while the sloth hangs upside down. In most conditions, the fur hosts two species of symbiotic algae, which provide camouflage. Because of the algae, sloth fur is a small ecosystem of its own, hosting many species of non-parasitic insects. Sloths have short, flat heads, big eyes; short snouts, long legs, and tiny ears. Some species have stubby tails (6–7 cm long). Altogether, sloths’ bodies usually are between 50 and 60 cm long.