Ballistic penises and corkscrew vaginas - the sexual battles of ducks

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    Dec 23, 2009 5:43 PM GMT
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    http://tinyurl.com/yljgds8

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    Patricia Brennan from Yale University is trying to encourage male Muscovy ducks to launch their ballistic penises into test tubes.

    Normally, the duck keeps its penis inside-out within a sac in its body. When the time for mating arrives, the penis explodes outwards to a fully-erect 20cm, around a quarter of the animal's total body length. The whole process takes just a third of a second, and Brennan captures it all on high-speed camera. This isn't just bizarre voyeurism. Duck penises are a wonderful example of the strange things that happens when sexual conflict shapes the evolution of animal bodies.

    Many ducks form bonds between males and females that last for a mating season. But rival males often violently force themselves onto females. To gain the edge in these conflicts, drakes have evolved large corkscrew phalluses, lined with ridges and backward-pointing spines, which allow them to deposit their sperm further into the female than their rivals. These extreme penises of ducks are even more unusual because 97% of birds lack any penises whatsoever.

    But female ducks have developed countermeasures. Their vaginas are equally long and twisting, lined with dead-end pockets and spirals that curve in the opposite direction. They are organic chastity belts, evolved to limit the effectiveness of the males' lengthy genitals. Two years ago, Brennan showed that duck species whose males have the longest penises tend to have females with the most elaborate vaginas. Now, she has found further evidence that these complex genitals are the result of a long-lasting war of the sexes.

    Duck penises (and those of birds, in general) work in a different way to human ones. For a start, they are flexible when erect. Human penises stiffen thanks to an onrush of blood; for ducks, it's lymph that does the job. Finally, human males get erections before having sex but drakes evert their penis directly into the female's vagina.

    That presents a problem - to really study the mechanics of the duck penis, you can't just fluff the animal. You need to give it something to have sex with. That's where the glass tubes come in. Brennan used four different shapes: a straight tube; a counterclockwise helix that matches the spiral of the male's penis; a clockwise spiral going in the opposite direction; and a tube with a sharp 135 degree kink, that mimics the position of the first cul-de-sac pouch in the female's vagina.

    Brennan took these tubes to a commercial duck farm in California, where Muscovy drakes provide semen for artificial insemination. She watched as the handlers placed a female the same cage as a randy drake, and waited until the male mounted her. Just as he was getting ready to mate, Brennan intercepted him with one of the four oiled tubes, touching it to a pair of sensitive spots that immediately trigger the explosive erection and ejaculation.

    Her videos revealed the process of duck erection in painstaking detail, including how long it takes to evert the different parts of the penis, how fast the ejaculate is and how long it takes to retract the appendage (around 2 minutes). They showed that the drakes easily launched their penises into the straight tubes and the ones that matched the direction of their spiral. The tubes that spiralled in the wrong direction or bent at a sharp angle proved to be more challenging, and mostly stopped the males from achieving a full erection.

    So the shape of the female duck's vagina is a physical barrier that prevents the male from launching forth his ballistic penis to its fullest extent. It won't stop a drake from ejaculating (and those in Brennan's trials always did), but it does limit how far the semen is deposited along the vaginal tract.

    Not all males are hit equally hard by these defences. Those that the female actually wants to mate with have an easier time. If she's into a male, she strikes a pose that signals her receptiveness, keeping her body level and lifting her tail feathers high. She repeatedly contracts the walls of her genital tract, relaxing them for long enough for favoured suitors to achieve full penetration.

    Males who try to force themselves upon her receive no such help and have to cope with vigorous struggling. The female may not be able to resist such advances, but her convoluted vagina gives her ultimate control over where the sperm of her current partner ends up. The fact that only 3% of duck offspring are born of forced matings suggests that females are indeed winning this battle of the sexes. Clearly, it's not size that matters, but what she lets you do with it that counts.
  • Posted by a hidden member.
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    Dec 23, 2009 7:49 PM GMT
    That was a wee bit disturbing.icon_eek.gif
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    Dec 23, 2009 8:05 PM GMT
    WTF??? I don't feel so good...

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    Dec 23, 2009 8:09 PM GMT

    nonna my business. icon_surprised.gif
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    Dec 23, 2009 8:17 PM GMT
    fascinating....
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    Dec 23, 2009 8:35 PM GMT
    omg icon_eek.gif
  • Sparkycat

    Posts: 1064

    Dec 23, 2009 8:45 PM GMT
    Is that video online? Not that I want to see it. I just asking in case anyone else does.
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    Dec 23, 2009 8:49 PM GMT
    a muscly zoology nerd *swoon*
  • CarbGoggles

    Posts: 705

    Dec 23, 2009 9:05 PM GMT
    I'm going to start saying hung like a duck from now on lol.
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    Dec 23, 2009 9:20 PM GMT
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    Dec 23, 2009 9:23 PM GMT
    dustin_K_tx said876.gif




    I can't stop watching this. What's wrong with me???

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    Dec 23, 2009 9:23 PM GMT
    ^ I seriously thought that was a real scene. I was wondering how I missed that episode, then I saw the 'shop job. Good one.
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    Dec 23, 2009 9:37 PM GMT
    This is now my all time favorite Forum ever... I mean the title alone is priceless.

    Who know you could learn so much on RJ

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  • J450N

    Posts: 75

    Dec 23, 2009 10:07 PM GMT
    O.o WTF?
  • jrs1

    Posts: 4388

    Dec 23, 2009 11:24 PM GMT

    fascinating. truly.
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    Dec 23, 2009 11:52 PM GMT
    ooers interesting... Don't know if I'd ever want an explosive flaccid projectile penis but interesting none the less
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    Dec 23, 2009 11:57 PM GMT
    This article reminds me of the way bedbugs reproduce. icon_lol.gif
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    Dec 24, 2009 12:43 AM GMT
    That was something, very, can't find the rights words.
  • offshore

    Posts: 1294

    Dec 24, 2009 12:59 AM GMT
    Facinating! People who denile Evolution should try explain these away... Maybe god rally was bored out of his mind...
  • Sparkycat

    Posts: 1064

    Dec 24, 2009 4:07 AM GMT
    OMG Only if you have a strong stomach should you click on the link in the O.P.'s orignal post. I've never seen anything so bizarre in my life. But, I must say ducks are hung like horses.
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    Dec 24, 2009 4:13 AM GMT
    icon_eek.gif Good Lord I need a drink
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    Dec 24, 2009 11:48 AM GMT
    That is one cool cock. I wonder what other animals have aggressive cockage?? I know mine's like a sledge hammer.
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    Dec 24, 2009 11:52 AM GMT
    justskeevin saidThat is one cool cock. I wonder what other animals have aggressive cockage?? I know mine's like a sledge hammer.


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    Dec 24, 2009 4:15 PM GMT
    Well, according to The Straight Dope, the pig also has a corkscrew-shaped penis:

    http://www.straightdope.com/columns/read/50/does-a-pig-have-a-corkscrew-shaped-penis

    The corkscrew penis is now my favorite example of convergent evolution.
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    Dec 26, 2009 12:39 PM GMT
    Wow. Now I feel stoopit for not knowing about the Straight Dope... But I will now peruse it regularly. Thanks!