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
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
Dieters who sleep more take off more fat that those who sleep less.
159
47% of people have a nightmare at least once a month.
186
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