A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
The higher someone’s I.Q. the more likely they are to be sleep deprived.
29
Cows can sleep standing up, but they can only dream lying down.
745
Honeybees never sleep.
276
If you hold farts in during the day, they'll just come out when you sleep.
16
Bats sleep 18-20 hours per day.
5
Lack of water is the #1 trigger of daytime fatigue.
148