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
Honeybees never sleep.
276
The human brain is more active during sleep than during the day.
28
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
You burn more calories sleeping than you do watching television.
348
47% of people have a nightmare at least once a month.
186
Bats sleep 18-20 hours per day.
5