The Brown-throated Sloth (Bradypus variegatus), or brown-throated three-toed sloth, is a species of three-toed sloth native to Central and South America. The main difference between three-toed and two-toed sloths is their claws. All sloths have three claws on their hindlimbs, but two-toed sloths have two claws on their forelimbs, while three-toed sloths have three claws. The two-toed sloths have golden fur, no eye markings, and a lighter colored snout. The three-toed sloth has brown fur, with some species having yellow and black markings on their backs. They also have a brown snout and brown eye markings.
Sloths are the slowest land mammals and pace through the canopy at an average of 0.15 mph (0.24 km/h). They're so slow that algae can grow on their backs, creating a micro-habitat for beetles and moths. This algae can provide as camouflage, so from far away, predators like jaguars and harpy eagles might mistake them to just be part of the green scenery. Sloths are also slow so predators won't spot them. Sloths are surprisingly good swimmers and will cross a body of water to avoid predators and find more food across the river. They are about two times faster when swimming than when they're in the trees.
Sloths evolved to be so slow in the first place because of the food they eat. The leaves they eat don't have much energy or nutrition in them. Some herbivores like the giant panda spend most of their day eating energy deficient bamboo stalks to get the energy that they need daily to function. So instead of eating a lot of leaves all day, sloths slow down their pace. The few leaves they do eat will go a long way because they move so slow. Digestion of their food is slow, too. It can take more than a month for them to finish digesting a meal of leaves, which makes them smell very unpleasant.
Sloths are really good with muscle control in their arms and can keep their arms from getting tired hanging upside-down. Sloths are also the only mammals that have fur that grows away from the extremities (hands and feets). Their fur parts on the middle of their bellies. So when their hanging upside-down during a rain shower, the rain will hit their fur and just run right off. Sloths and manatees are also the only mammals that can have more or less than seven cervical vertebrae in their neck.
Every week, a sloth comes down from hanging upside-down to go to the bathroom. Some scientists think they poop at the base off the tree to mark their territory and to fertilize the tree they live in. They often squat and do what scientists call a "poo-poo dance". The time when they go down to the bathroom makes them very vulnerable to attack from predators, especially from behind. But sloths can turn their heads backwards 280° like an owl to spot predators.