You forget 90% of your dreams.
256
Honeybees never sleep.
276
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
Bats sleep 18-20 hours per day.
5
The strangers in your dreams are actually people that you've seen in real life.
50
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23