You forget 90% of your dreams.
256
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Bats sleep 18-20 hours per day.
5
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
A new baby usually deprives each of it's parents around 350-400 hours of sleep in the first year. That is one entire nights sleep per week, per parent.
194
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