Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
Lack of water is the #1 trigger of daytime fatigue.
148
Some people have a "natural alarm clock" allowing them to wake up when they want. This is actually caused by a burst of the stress hormone adrenocorticotropin.
15
Bats sleep 18-20 hours per day.
5
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23