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

While it’s clear that tree-dwelling lifestyles necessitate small bodies, scientists weren’t sure why ground sloths specifically demonstrated such vast size diversity. To investigate this ...

the size of sloths hardly changed at all for about 20 million years, irrespective of their preferred method of locomotion. Then something earth-shattering occurred. A giant wound opened up between ...

Sloths weren’t always the slow, tree-hugging creatures we know today. For millions of years, they came in a wild variety of ...

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.

Giant sloths with razor-sharp claws and as large ... And, because the scientists were particularly interested in how sloths got their size, they estimated their weights by taking fossil measurements.

Giant sloths used to roam all over North America ... and whether they were climbers or walkers. Since sloth size was a major question, they measured museum fossils to estimate the sloth weight.

By analyzing fossil DNA and environmental data, researchers discovered their size was closely linked to climate changes. Ancient sloths lived in trees, mountains, deserts, boreal forests, and open ...