The extinct mammals were about five times larger than a grizzly bear–and filled caves with their poop.

A new fossil and DNA analysis traces how dozens of sloth species responded to climate shifts and humans. Just two small tree-dwelling sloths remain today.

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 ...

An analysis of the sloth family tree suggests three different groups of the animals evolved to gigantic sizes in response to ...

A gigantic woolly mountain rat has finally been captured on camera deep in New Guinea’s remote forests.