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

Their prehistoric ancestors were huge — up to 4 tons — and when startled, they brandished immense claws. For a long time, scientists believed the first humans to arrive in the Americas soon ...

Research from several sites is starting to suggest that people came to the Americas earlier than once thought.

Sloths weren’t always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to 4 tons — and when ...

Their prehistoric ancestors were huge — up to 4 tons (3.6 metric tons) — and when startled, they brandished immense claws. For a long time, scientists believed the first humans to arrive in ...

Their prehistoric ancestors were huge — up to 4 tons (3.6 metric tons) — and when startled, they brandished immense claws.