Sloths are known for two things: being very slow and very cute. They come in both two-toed and three-toed species. Two-toed sloths are mostly nocturnal while three-toed sloths are active mostly during the day. All sloths move very slowly and only when necessary because they have only one quarter the muscle mass of other similar-sized animal species. All sloths can typically be found lounging in the treetop canopies of tropical jungle regions.