Imagine a sloth. You probably picture a medium-sized, tree-dwelling creature hanging from a branch. Today's sloths—commonly featured on children's backpacks, stationery and lunch boxes—are slow-moving ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Modern sloths hang ...

Credit: flickr You wouldn’t expect it from an animal that barely moves, but sloths are excellent swimmers. They use a sort of doggy paddle and can hold their breath for up to 40 minutes. Water ...