A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
You burn more calories sleeping than you do watching television.
348
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15