The human brain is more active during sleep than during the day.
28
Bats sleep 18-20 hours per day.
5
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
Sleeping on the job is acceptable in Japan. It is viewed as exhaustion from working hard. Some people fake it to look committed to their job.
57
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