Cows can sleep standing up, but they can only dream lying down.
745
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
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
"Dysania" is the state of finding it hard getting up out of bed in the morning.
33
47% of people have a nightmare at least once a month.
186