How do sloths move so slowly without running out of energy?

Sloths are famous for moving at a crawl, but that slowness is part of their survival strategy. They eat leaves, which are tough to digest and provide relatively little energy, so their bodies burn fuel slowly. A low metabolic rate helps them survive on a limited diet in tropical forests. Their slow movement also makes them harder for predators to notice. The downside is that they can be vulnerable on the ground, where they move much less safely than in trees.