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Why Men Don't Have Sensory Whiskers and Spiny Genitals 226

Posted by samzenpus
from the we'd-need-different-pants dept.
sciencehabit writes "Most male mammals wield a penis covered with spines made of keratin, the same material that forms fingernails, to sweep out competitors' sperm and irritate a female into ovulating. Even chimpanzees, our closest relatives, have penile spines. So why don't men? A new study suggests that this feature disappeared due to a chunk of DNA that went missing after our evolutionary divergence from chimps. The researchers have identified another DNA deletion that may have contributed to humans' bigger brains."
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Why Men Don't Have Sensory Whiskers and Spiny Genitals

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  • ...because I refrain from sex with porcupines and hedgehogs. And I didn't even have to RTFA.

    You mean like these 2 Russians [mosnews.com]

    Anton, 32, and Yevgeny, 30, residents of St. Petersburg, were spending their vacation in the United States with a group of friends, Life.ru website reports.

    At some point in their journey, the two got hold of a booklet listing the weirdest US laws. Since they were in Florida, their attention was drawn to a Florida law prohibiting sex with porcupines.

    After a good deal of whiskey, the Russians felt curious about what might have prompted the law, and went in search of the animal.

    Within one hour, a porcupine was found, and Anton and Yevgeny were drunk and brave enough to take off their pants and approach it.

    The next morning, both were standing at the Cedars Sinai clinic in Los Angeles, where amazed doctors plucked porcupine needles from their penises.

  • Occam's Razor (Score:5, Interesting)

    by argStyopa (232550) on Thursday March 10, 2011 @01:52PM (#35445570) Journal

    ...because women, generally, don't want them? They by & large run the reproductive sweepstakes, even back in the "me big strong caveman, me conk woman on head" days when "consent" was a little more broadly interpreted.

    And which came first, male lack of spines, or female concealed ovulation?

    When analyzing the genetic record, how can one 'sort out' the distinction between DNA changes that have happened due to mutation, compared to the changes induced by broad and consistent female choice?

  • Re:Occam's Razor (Score:2, Interesting)

    by Anonymous Coward on Thursday March 10, 2011 @03:06PM (#35446586)

    That's all fine and dandy, but considering that presumably, females of other species don't want them, either, why do they still exist there?

  • by deimios666 (1040904) on Thursday March 10, 2011 @03:17PM (#35446750)

    Still in the genepool only very diluted: https://secure.wikimedia.org/wikipedia/en/wiki/Hirsuties_coronae_glandis [wikimedia.org]

  • by smellsofbikes (890263) on Thursday March 10, 2011 @03:50PM (#35447132) Journal

    First off, human males *do* have a mechanism to sweep out sperm from other males, consisting of the most visually obvious part of the male penis and protracted mechanical movement. We lost spikes, we evolved something else to do the same function. Secondly, there are many other mammals that have different methods for accomplishing the same thing: male squirrels have something like superglue that forms a plug after coitus, to prevent other males gaining access afterwards. (And female squirrels have claws and quite a bit of expertise in removing those same plugs, as you'd expect in any good arms race.) Likewise, many male lizards and insects avoid the problem by just staying connected until the female is ready to lay her eggs, which puts a whole lot of stress on the female during that period: they both get eaten pretty often.

    But if you really want to get weird, go look at insects like bedbugs, where males practice traumatic insemination: they don't go looking for an orifice, they make one, and let the female's body figure out what to do with the results. Or bees, where the barbs aren't there to stimulate ovulation but to make sure the penis breaks off and acts as a plug that can't be removed.

    And the next step weirder is hermaphrodites, where mating is a contest in which both wish to inseminate the other without getting inseminated, so mating strategies get seriously complicated. (The phrase 'penis fencing' has been used.)

    Anyone who is curious about this should read the brilliant book Promiscuity: the evolutionary history of sperm competition [amazon.com] by Tim Birkhead. It will make you relieved to be human.

  • Re:Huh? (Score:5, Interesting)

    by tloh (451585) on Thursday March 10, 2011 @04:10PM (#35447318)

    What, you mean these spines on my penis aren't normal?.

    Let's hope it stays that way. from the article:

    "The interesting question - which for some reason the scientists didn't want to answer - is whether we could use a gene therapy to replace that deleted regulatory DNA. Basically, we'd add an activation switch to the whisker/spine sequence, flip it to "full blast," and start growing new body parts."

    I for one, do not think man should have his hands in his genes fiddling with himself. But then again, this is slashdot afterall, so...............

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