Those who get out of bed by 7am are more likely to be thinner and happier.
20
Cows can sleep standing up, but they can only dream lying down.
745
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
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
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