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

Researchers in Costa Rica have unearthed fossils from a mastodon and a giant sloth that lived as many as 40,000 years ago, ...

SAO PAULO (AP) — 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 ...

Sometimes it nice to just kick back and take it slow. Really slow. So what if evolution had the same mindset, and decided to ...

Most of us are familiar with sloths, the bear-like animals that hang from trees, live life in the slow lane, take a month to digest a meal and poop just once a week. Their closest living relatives are ...

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, ...

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: ...