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
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
Termites work 24 hours per day and they do not sleep.
57
Bats sleep 18-20 hours per day.
5
Lack of water is the #1 trigger of daytime fatigue.
148
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149