A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Termites work 24 hours per day and they do not sleep.
57
Honeybees never sleep.
276
The human brain is more active during sleep than during the day.
28
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
Cows can sleep standing up, but they can only dream lying down.
745