For years, scientists could only guess when wild animals were asleep. Now, miniaturized versions of sleep lab equipment are revealing the extreme and somewhat quirky ways animals snooze while flying, ...

Studying ancient sea creatures’ snoozing habits could shed light on the origins of sleep.

Scientists already knew that the pair of shallow coastal ocean dwellers keep very different schedules of downtime: The ...

Ever wonder how animals sleep in the wild? It's not always as you may think. From sloths who hang upside down from trees to dolphins sleeping with one eye open, the animal kingdom is full of quirky ...

Most animals don’t keep the same schedule we do. While we try to squeeze in eight hours and call it a good night, many animals snooze through more than half the day—and some barely stay awake at all.