A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
22
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
47% of people have a nightmare at least once a month.
186
Termites work 24 hours per day and they do not sleep.
57
People who sleep late have more mental stamina and can outperform early risers.
33
Sea otters hold hands while sleeping so they don’t drift away from each other.
104