Three-toed Sloth

Three-toed Sloth

The three-toed sloths are tree-living mammals from South and Central America. They are the only members of the genus Bradypus and the family Bradypodidae. There are four living species of three-toed sloths. These are the Brown-throated Sloth, the Maned Sloth, the Pale-throated Sloth, and the Pygmy Three-toed Sloth.

Although similar to the somewhat larger and generally faster moving two-toed sloths, the two genera are placed in different families. Recent phylogenetic analyses support the morphological data from the 1970s and 1980s that the two genera are not closely related and that each adopted their arboreal lifestyles independently. It is unclear what ground-dwelling sloth taxa the three-toed sloths evolved from; the two-toed sloths appear to nest phylogenetically within one of the divisions of Caribbean megalonychids, and thus probably either descended from them or are part of a clade that invaded the Caribbean multiple times. Both types of sloth tend to occupy the same forests: in most areas, a particular single species of three-toed sloths and a single species of the larger two-toed type will jointly predominate. Famously slow-moving, the sloth travels at a top speed of 0.24 kilometres per hour (0.15 mph).

Although they are quite slow in trees, three-toed sloths are agile swimmers. The offspring cling to their mother's bellies for around 9 months or so. They cannot walk on all four limbs, and so they must use their front arms and claws to drag themselves across the rain forest floor. They do not have a mating season and breed year round.

The three-toed sloth is arboreal (tree-dwelling), with a body adapted to hang by its limbs. It lives high in the canopy but descends once a week to defecate on the forest floor. Its long, coarse, grayish-brown fur often appears greenish, not due to pigment but to algae growing on it. The sloth’s greenish color and its sluggish habits provide an effective camouflage: hanging quietly, the sloth resembles a bundle of leaves. Large curved claws help the sloth to keep a strong grip on tree branches.