Among the greatest mysteries of the tropical rainforest are the pooping habits of sloths. Really. Those furry, slow-moving tree dwellers almost never descend from the safety of the tree tops—except ...

Meet the world’s first sloth detective dog, Keysha. Meet the world’s first sloth detective dog, Keysha —trained to sniff out sloth poop and empower the world’s first ever sloth census!

Valentino is a baby Linnaeus’s two-toed sloth. At five months old, he weighs about as much as a cantaloupe (and only moves slightly more). Everything he does, little that may be, is beyond adorable.

Ancient sloths lived in trees, on mountains, in deserts, boreal forests and open savannahs. These differences in habitat are primarily what drove the wide difference in size between sloth species.

While humans wouldn’t be very happy to find that organisms were growing on their skin, particularly fungi, algae, and insects, it works out pretty well for sloths. Sloths may be hosting entire ...

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