The mammal known to spend most of its life hanging upside down in rainforest trees is the sloth. Its body is specially adapted for a suspended life in the tropical forests of Central and South America.
Sloths have long, curved claws that hook securely around branches, allowing them to eat, sleep, and move while hanging. Their limbs are better suited to grasping and suspension than to walking. On the ground, most sloths can only drag themselves slowly, so they remain in the canopy whenever possible.
Their famously slow movements are an energy-saving adaptation. Sloths mainly eat leaves, which provide limited nutrition, and their low metabolic rate helps them survive on this diet. Their coarse fur can also support algae, giving some individuals a greenish tint that helps camouflage them among leaves.
The word “sloth” covers several living species in two groups: three-toed sloths and two-toed sloths. Despite the names, both groups have three toes on each hind foot; the distinction refers to the number of digits on the forelimbs.