Narrator Tom Hiddleston teases "remarkable creatures and epic clashes for survival" in a sneak peek at 'Prehistoric Planet: ...

Sloth in prison -- The Great Basin now and then -- A zoologically impoverished world -- Dating an ass -- A stable of ground sloths -- Extinct mammals, dangerous plants, and the early peoples of the ...

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, ...