Did you know crocodile dung was one of the earliest forms of birth control?
Ancient Egyptians used a pessary made of dried crocodile dung as a contraceptive. The substance contained spermicidal properties similar to those used on condoms.
How they discovered its contraceptive properties is a whole other issue. Was it just a lucky guess or did they actually go through a "trial and error" experiment with anything they could think of?
So now you know.