We were lucky enough to get some fun video footage of two flatworms mating (a spot voyeuristic perhaps) on one of our recent snorkeling trips in Salt Rock.... an act that is literally called "penis fencing" and can last up to an hour in some species! 

In case you missed our previous article on Unusual mating habits in the ocean, Flatworms are hermaphrodites, by default both male and female. Unable to have a logical conversation about the matter, the flatworms solve the problem in the only way they know how: by trying to stab the other with their penis and the first to inseminate the other wins. If you look closely in this little clip, you can actually see this unusual battle taking place. That odd little appendage just below the Flatworm's head is yes, his penis (or hers, you decide)