Cows can sleep standing up, but they can only dream lying down.
745
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
The average cat sleeps about 2/3 of the day.
203
The human brain is more active during sleep than during the day.
28