Long before today’s tree-dwelling sloths, a 4-ton giant roamed South America — and it may have stood and fought like a bear.

This video reveals why sloths move so slowly that algae is able to grow directly on their fur. Viewers learn how this surprising relationship helps camouflage the animals and support tiny organisms ...

It’s not considered polite to talk about it, but we all do it. Some of us are in and out so quickly that nobody would even know we were gone. Others quietly get up from the sofa, tuck a newspaper ...