A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The higher someone’s I.Q. the more likely they are to be sleep deprived.
29
"Dysania" is the state of finding it hard getting up out of bed in the morning.
33
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
Bats sleep 18-20 hours per day.
5
The human brain is more active during sleep than during the day.
28