Sloths weren't always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to 4 tons (3.6 metric tons ...

Huge tunnels under southern Brazil and northern Argentina were potentially made by giant, Ice Age sloths for refuge and rest ...

Sloths weren't always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to 4 tons (3.6 metric tons) — and when startled, they brandished immense claws.Video above: ...

It's so nice to know where we come from, how we migrated, not only when we got here but how we got here and how we were living. Scientists mostly agree that the first humans in the Americas arrived ...