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 burn more calories sleeping than you do watching television.
348
The average cat sleeps about 2/3 of the day.
203
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
The strangers in your dreams are actually people that you've seen in real life.
50