Imagine a sloth. You probably picture a medium-sized, tree-dwelling creature hanging from a branch. Today's sloths—commonly featured on children's backpacks, stationery and lunch boxes—are slow-moving ...

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 ...

Here’s what heaven looks like to a sloth: Hanging out in a rain forest, rarely coming down from the verdant canopy where they are safe from predators; moving slowly, basking in the sun and eating just ...