Sloth - Ecology

Ecology

Sloths are classified as folivores as the bulk of their diet consists 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 diet. Linnaeus's two-toed sloth has recently been documented eating human faeces from open latrines. They have made extraordinary adaptations to an arboreal browsing lifestyle. Leaves, their main food source, provide very little energy or nutrition and do not digest easily. Sloths therefore have large, specialized, slow-acting stomachs with multiple compartments in which symbiotic bacteria break down the tough leaves. As much as two-thirds of a well-fed sloth's body-weight consists of the contents of its stomach, and the digestive process can take a month or more to complete.

Even so, leaves provide little energy, and sloths deal with this by a range of economy measures: they have very low metabolic rates (less than half of that expected for a mammal of their size), and maintain low body temperatures when active (30–34 °C or 86–93 °F), and still lower temperatures when resting.

Although unable to survive outside the tropical rainforests of South and Central America, within that environment sloths are outstandingly successful creatures. Four of the six living species are presently rated "least concern"; the maned three-toed sloth (Bradypus torquatus), which inhabits Brazil's dwindling Atlantic Forest, is classified as "endangered", while the island-dwelling pygmy three-toed sloth (B. pygmaeus) is critically endangered.