A drawing showing a dead giant ground sloth with cut marks. We see two human hands crafting the sloth's bone. The date that humans arrived in South America has been pushed back to at least 25,000 ...

Sloths weren’t always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to 4 tons — and when startled, they brandished immense claws. For a long time, scientists believed ...

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: ...

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. For a long time, ...