Cows can sleep standing up, but they can only dream lying down.
745
A new baby usually deprives each of it's parents around 350-400 hours of sleep in the first year. That is one entire nights sleep per week, per parent.
194
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
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
Bats sleep 18-20 hours per day.
5
Some people have a "natural alarm clock" allowing them to wake up when they want. This is actually caused by a burst of the stress hormone adrenocorticotropin.
15