How do sloths sleep upside down without letting go?

Sloths are really, really good at hanging upside down. They practically make it seem effortless! Why is that? Do they love it? Is the world just more fun from that angle? We asked zoologist Lucy Cooke to help us figure it out.Got a question that’s clawing at your brain? Send it to us at BrainsOn.org/contact, and hang in there - we’ll help you find the answer.