A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Cows can sleep standing up, but they can only dream lying down.
745
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
"Dysania" is the state of finding it hard getting up out of bed in the morning.
33
The human brain is more active during sleep than during the day.
28
The higher someone’s I.Q. the more likely they are to be sleep deprived.
29