A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Lack of water is the #1 trigger of daytime fatigue.
148
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
The higher someone’s I.Q. the more likely they are to be sleep deprived.
29
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
The strangers in your dreams are actually people that you've seen in real life.
50