47% of people have a nightmare at least once a month.
186
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
The strangers in your dreams are actually people that you've seen in real life.
50
You forget 90% of your dreams.
256
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Honeybees never sleep.
276