Three-toed sloths have a reputation for being some of the sleepiest of all animals, largely due to a single study, which found that captive sloths snooze for 16 hours a day. That certainly seems like a sweet deal to me, but it seems that the sloth’s somnolent reputation has been exaggerated.  

A new study – the first ever to record brain activity in a wild sleeping animal – reveals that wild sloths are far less lethargic than their captive cousins. In their natural habitat, three-toed sloths sleep for only 9.6 hours a day, not much more than an average first-year university student.

For something so routine, the function and evolutionary origins of sleep are still fairly enigmatic. One approach