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
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
Bats sleep 18-20 hours per day.
5
You burn more calories sleeping than you do watching television.
348
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212