Flatworms, also called "planarians," are found just about everywhere there is water. There are many different species of flatworms, but Procotyla fluviatilis, one of our more common ones. They can grows up to 20 millimeters long.  
There are no male or female flatworms. They are hermaphrodites, which means when they mate, both flatworms can lay eggs.  
The fight begins neither one wants the responsibility of being the mother having to feed and protect the off-spring. They both want to be free and tend to themselves. They use their penis to fight each other. Each one trying to get their penis inside the other one. The winning of the fight is the one who gets his load of first inside the other.....  
Would you be happy with this way of reproduction?  


-- Modified on 1/27/2015 11:01:49 AM