The average cat sleeps about 2/3 of the day.
203
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
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
People who sleep late have more mental stamina and can outperform early risers.
33
Bats sleep 18-20 hours per day.
5
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