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 ...

Athena was a sloth who lived at the National Zoo in Washington, and, according to the zoo, was a much beloved creature who had showed that sloths need not be slothful. Instead, she had been spirited ...