Cows can sleep standing up, but they can only dream lying down.
745
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
The strangers in your dreams are actually people that you've seen in real life.
50
You forget 90% of your dreams.
256
The average cat sleeps about 2/3 of the day.
203
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149