Some young sloths are so inept that they will frequently grab their own arms and legs instead of tree branches and fall out of trees.
Sloths move so slow that it is common for algae to grow in their fur. They are also host ‘nests’ for beetles and moths.
Sloths’ claws serve as their only natural defense. A cornered sloth may swipe at its attackers in an effort to scare them away or wound them. Despite sloths’ apparent defenselessness, predators do not pose special problems: sloths blend in with the trees and, moving only slowly, do not attract attention. Only during their infrequent visits to ground level do they become vulnerable. The main predators of sloths are the jaguar, the harpy eagle, and humans. The majority of recorded sloth deaths in Costa Rica are due to contact with electrical lines and poachers. Their claws also provide a further unexpected deterrent to human hunters; when hanging upside-down in a tree, they are held in place by the claws themselves and often do not fall down even if shot from below.