The human brain is more active during sleep than during the day.
28
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
The average cat sleeps about 2/3 of the day.
203
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
Honeybees never sleep.
276