In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
The average cat sleeps about 2/3 of the day.
203
Cows can sleep standing up, but they can only dream lying down.
745
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
If you hold farts in during the day, they'll just come out when you sleep.
16
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34