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
Bats sleep 18-20 hours per day.
5
47% of people have a nightmare at least once a month.
186
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
The human brain is more active during sleep than during the day.
28
If you hold farts in during the day, they'll just come out when you sleep.
16
The average cat sleeps about 2/3 of the day.
203