A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
When Washoe, the first chimp to use sign language, was told that her caretaker's baby had died, she signed "CRY."
20
Jumping fleas can accelerate 50 times faster than the space shuttle.
218
A group of kittens is called a "kindle".
10
The largest earthworm on record was found in South Africa and measured 22 feet.
151
Cats are one of the only animals to domesticate themselves and approach humans on their own terms.
20
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212