Sloths once roamed the Americas, ranging from tiny, cat-sized animals that lived in trees all the way up to massive ground sloths that may have weighed up to six tons. The only species we know and ...

Sloths, the world's slowest mammals, have evolved over 64 million years into a species that thrives throughout Central America and northern South America, but climate change and human sprawl could be ...

There are degrees of slothfulness, it turns out, even when it comes to sloths. And three-toed sloths may be the most slothful of them all: A species of the animal has a field metabolic rate that is ...