Cows can sleep standing up, but they can only dream lying down.
745
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
Sea otters hold hands while sleeping so they don’t drift away from each other.
104
The human brain is more active during sleep than during the day.
28
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
Termites work 24 hours per day and they do not sleep.
57
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23