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
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
The average cat sleeps about 2/3 of the day.
203
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
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