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
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
You burn more calories sleeping than you do watching television.
348
Bats sleep 18-20 hours per day.
5
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
A new baby usually deprives each of it's parents around 350-400 hours of sleep in the first year. That is one entire nights sleep per week, per parent.
194
People who sleep late have more mental stamina and can outperform early risers.
33
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193