Do All Creatures Sleep?

Scientists used e gs to monitor which stage of sleep subjects were in. They then wake them up at different stages and asked if they could remember dreaming. Dreaming is most common in rim sleep, but it also occurs in every cycle. Sleep is universal among animal life - even very primitive worms enjoy periods of slumber. Hear's what matthew walter, one of the world's top experts on sleep science says in his book, why we sleep.