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
If you hold farts in during the day, they'll just come out when you sleep.
16
47% of people have a nightmare at least once a month.
186
You burn more calories sleeping than you do watching television.
348
Cows can sleep standing up, but they can only dream lying down.
745