I’ll tell you the story of Henry Morgan…

2 May 2007

Male Argentine Duck, Oxyura vittata, with extruded 32.5 cm long phallus.


I wasn’t even aware that I actually knew any dirty limericks, but when I saw this PLoS One paper one popped from the depths of my subconscious like a roach emerging from beneath a rock:

I’ll tell you the tale of Dead Eye Mick
The only man with a corkscrew ‘intromittent organ’

He spent his life in a desperate hunt
For a woman who had a corkscrew ‘introreceptive organ’

When he found her he dropped down dead
The corkscrew
introreceptive organ’ had a left hand thread.

(unredacted version here – ADULT CONTENT WARNING!)

Actually the version I remembered was about Jolly Jacques…who was born with… well, you get the idea. Imagine my surprise/relief when I found the same limerick on Bora’s post about spiraling swine phalli (although his version is ‘Clarence Cool/Who was born with a spiral tool).

Anyway…if you’re the type to follow such things, you’ll no doubt recall Dr. Kevin McCracken, the man who was born with (sorry), who lead a team that published their discovery of a duck with a ‘almost half a metre long’ phallus (pictured above) as a brief communication in Nature [pdf].

Ducks are unusual among birds in having long phalli (footnote), in fact most birds don’t have phalli at all but copulate by means of a ‘cloacal kiss’. This endowment is possibly linked to their rather raucous (and from a human-perspective sometimes down-right nasty) mating habits which include forced copulation (rape) and group forced copulation (gang rape).

In their new paper, Patricia Brennan and coauthors (including McCracken) take a fresh perspective on the situation by examining the reproductive anatomy of female water-fowl…which, while less ‘in-your-face’ is no less remarkable.

In marked contrast to the traditional ho-hum ‘short, narrow muscular duct’ view of bird vaginae, they found a remarkable array of anatomical innovation in female ducks. These include dead-ends and a clockwise spiral that runs against the counter-clockwise spiraling phallus of the male!!!

These morphological novelties apparently provide females some leverage against well-equipped, but undesirable males. The acknowledgement of so-called ‘female choice’ has revolutionized our view sexual selection. The game is not simply an ‘inseminating contest’ between randy males, but a complex interplay among and between males and females with various coordinated and competing interests.

In fact the authors propose that the impressive phallus-length of male ducks may not be primarily a response to competition between males as has been largely assumed. Instead, they suggest the evolution of absurdly long duck-phalli may driven by the anatomical elaborations of the females…i.e. it’s the females driving morphological evolution not the males.

The new report has gotten a well deserved flurry of press, both in the blogosphere and a great Times article by Carl Zimmer, the man who was born with… Sorry, just trying to make up for missing National Poetry Month.

If you just can’t get enough of non-mammal intromittent organs may I suggest Darren’s recent post on turtle members?

1 – I’m avoiding using the term ‘penis’ not for decorum but due to the likelihood that the phallus of ducks is not homologus with mammal penes.


5 Responses to “I’ll tell you the story of Henry Morgan…”

  1. Oh, yeah, that’s the same limerick! And I also blogged about the duck a few months ago as well as last night.

  2. Laelaps Says:

    […] out yet (I’ll write a new post when I do) but if you’re looking for more on the topic Neil has a great analysis of the paper and Bora (as always) is the link-master to seemingly everyone who […]

  3. laelaps Says:

    Nice write-up Neil; I yet to actually read the paper (thank you for the link) but I’ll definitely post my thoughts when I get the chance. Like you mentioned in your initial comment, very often there is a phallus-centric view of sex selection and competition among males is often seen as the driving mechanism for some morphological change related to mating, but in fact females hold a lot of power to change males over time, which (at least at the moment) seems to make more sense to me with the lock & key genitals model. It’s hard for me to figure out how the males developed such elaborate genitals and the females just happened to go along with it, but in other cases it may very well have been sperm competition; we’d have to look at each species individually. Anyway, I have yet to read the paper but the female-driven sex selection sounds credible for certain species (it may not for others), but thank you for writing such a concise and funny summary.

  4. laelaps Says:

    Hi again Neil, I’ve read the paper and posted a few thoughts about it over on my blog; there’s certainly more questions than answers!


  5. […] 2007, the internet was ablaze with duck genitals. Brennan’s paper, Coevolution of Male and Female Genital Morphology […]

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