A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Dieters who sleep more take off more fat that those who sleep less.
159
Honeybees never sleep.
276
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
You forget 90% of your dreams.
256
Cows can sleep standing up, but they can only dream lying down.
745
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15