You burn more calories sleeping than you do watching television.
348
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
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
The average cat sleeps about 2/3 of the day.
203