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 ...

The researchers found that three-toed sloths can harbor more phoretic moths than their two-toed counterparts because of greater concentrations of inorganic nitrogen and higher algal biomass in their ...

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. But ...