Cows can sleep standing up, but they can only dream lying down.
745
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
Honeybees never sleep.
276
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
Bats sleep 18-20 hours per day.
5
The average cat sleeps about 2/3 of the day.
203