Penis Fencing

To borrow from the great comedic folk duo, Flight of the Chonchords “Yeah, you sexy hermaphrodite lady-man-lady, with your sexy lady bits, and your sexy man bits too, even you must be into you-oo-oo.” Hermaphroditism is common in marine invertebrates and the, flatworms are no exception.  Certain species of flatworm engage in a behavior called penis fencing.  Both swordsmen in this sexual fight are equipped with two-headed dagger-like penises.  The champion is the individual that inseminates the other by jabbing them.  The sperm is absorbed through the skin, and makes its way to the ovaries. The loser is fertilized and stuck with a bunch of crying little flatworms demanding energy and time.

Losers and winners are not always the case in hermamphrodites.  Often both are winners in which a mutual exhange of sperm occurs.

Dr. M (1720 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, created to facilitate research to address fundamental questions in evolutionary science. He has conducted deep-sea research for 11 years and published over 40 papers in the area. He has participated in dozens of expeditions taking him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses mainly on marine systems and particularly the biology of body size, biodiversity, and energy flow. He focuses often on deep-sea systems as a natural test of the consequences of energy limitation on biological systems. He is the author and chief editor of Deep-Sea News, a popular deep-sea themed blog, rated the number one ocean blog on the web and winner of numerous awards. Craig’s popular writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.

3 comments on “Penis Fencing
  1. Is there really a ‘loser’ or a ‘winner’? Or is this all just our perception of the interaction between two animals? I posted about this very clip earlier in the week and have provided a re-sound-tracked version of the penis fencing footage. I think it tells a different story, and suggests a different narrative.

  2. Pingback: In Penis Fencing Everyone Wins | Nakedcircus

  3. jebyrnes thanks so much for your redone video, with that music it really gives it a whole different look the whole mating fencing thing. Thanks to you both for such and interesting blog and site.

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