A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Sleeping on the job is acceptable in Japan. It is viewed as exhaustion from working hard. Some people fake it to look committed to their job.
57
The human brain is more active during sleep than during the day.
28
Bats sleep 18-20 hours per day.
5
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
If you hold farts in during the day, they'll just come out when you sleep.
16
You forget 90% of your dreams.
256