Sloths are famous for moving slowly, but that extreme pace has unexpected biological consequences. Because they spend so much time nearly motionless, algae can grow directly in their fur, turning the ...

Sloths look slow in a way that almost doesn’t feel real, but their sluggish movement isn’t a flaw or a weakness. Every part of their body is built around saving energy, avoiding danger, and surviving ...

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

Fans of the movie franchise Zootopia know that sloths make the perfect DMV (Department of Mammal Vehicles) workers.

It’s not considered polite to talk about it, but we all do it. Some of us are in and out so quickly that nobody would even know we were gone. Others quietly get up from the sofa, tuck a newspaper ...