You burn more calories sleeping than you do watching television.
348
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
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
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
Honeybees never sleep.
276
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149