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 average person falls asleep in seven minutes.
115
The higher someone’s I.Q. the more likely they are to be sleep deprived.
29
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
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
People who sleep late have more mental stamina and can outperform early risers.
33