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 ...

Add Yahoo as a preferred source to see more of our stories on Google. Ancient sloths lived in trees, on mountains, in deserts, boreal forests and open savannahs. These differences in habitat are ...

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 ...