One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212
The human brain is more active during sleep than during the day.
28
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
You burn more calories sleeping than you do watching television.
348
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Lack of water is the #1 trigger of daytime fatigue.
148