Bats sleep 18-20 hours per day.
5
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
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
44% of kids watch television before they go to sleep.
106
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
47% of people have a nightmare at least once a month.
186
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23