Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
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
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
Bats sleep 18-20 hours per day.
5