When a male gentoo penguin "falls in love" with a female penguin, he searches the entire beach to find the perfect pebble to present to her.
25
Rattlesnake mating sessions have been known to last more than 22 hours.
232
When Washoe, the first chimp to use sign language, was told that her caretaker's baby had died, she signed "CRY."
20
Female kangaroos have three vaginas.
2
The first known contraceptive was crocodile dung, used by Egyptians in 2000 B.C.
79