The human brain is more active during sleep than during the day.
28
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
You forget 90% of your dreams.
256
Honeybees never sleep.
276
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