A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
You can reschedule your sleeping pattern by not eating 12-16 hours before you want to be awake. Upon eating after this time period, your internal clock will reset to a new day, with the time of your first meal being interpreted as "morning".
11
There's a love mattress that is specifically designed for couples who sleep on each other's arms.
12
You forget 90% of your dreams.
256
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
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.
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