Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
You burn more calories sleeping than you do watching television.
348
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
The human brain is more active during sleep than during the day.
28
Cows can sleep standing up, but they can only dream lying down.
745
Bats sleep 18-20 hours per day.
5
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23