Birds exhibit unihemispheric sleep, a fascinating compromise between rest and survival. One half of their brain remains alert ...

Have you heard the saying about “sleeping with one eye open”? It’s a bit of metaphoric advice about staying vigilant—and a way to describe very light restless sleep. But sleeping with eyes open is ...

Cats do some pretty weird things. If you share your home with one, you could probably list a few. Sometimes, their behaviors give their owners a good chuckle, like when they sleep in cardboard boxes, ...

Animals have evolved to sleep in extreme ways — for example, taking micro naps during parenting, sleeping on the wing during ...