A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
Bats sleep 18-20 hours per day.
5
The strangers in your dreams are actually people that you've seen in real life.
50
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
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
You can reschedule your sleeping pattern by not eating 12-16 hours before you want to be awake. Upon eating after this time period, your internal clock will reset to a new day, with the time of your first meal being interpreted as "morning".
11
Termites work 24 hours per day and they do not sleep.
57