Today, sloths are slow-moving, tree-dwelling creatures that live in Central and South America and can grow up to 2.5 feet long. Thousands of years ago, however, some sloths walked along the ground, ...

Giant sloths with razor-sharp claws and as large as Asian bull elephants once roamed the Earth, snacking on leaves at the tops of trees with a prehensile tongue. Now, scientists have figured out why ...

The sloth family tree once sported a dizzying array of branches, body sizes and lifestyles, from small and limber tree climbers to lumbering bear-sized landlubbers. Why sloth body size was once so ...

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.

Most of us are familiar with sloths, the bear-like animals that hang from trees, live life in the slow lane, take a month to digest a meal and poop just once a week. Their closest living relatives are ...

Scientists have analyzed ancient DNA and compared more than 400 fossils from 17 natural history museums to figure out how and why extinct sloths got so big. Most of us are familiar sloths, the ...