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
People who sleep late have more mental stamina and can outperform early risers.
33
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
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
Those who get out of bed by 7am are more likely to be thinner and happier.
20
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The average cat sleeps about 2/3 of the day.
203