Animal-sex Friday

It's Friday, and you know what that means. Yes, blogger Scicurious (who brought us the whale threesome) has another post about animal sex research.

This time, it's about chicken sperm. Specifically, whether roosters alter the quality of their sperm depending on how many other roosters they think have been, uh, laying with their hen—and what social status the hen, herself, has.


Believe it or not, studies in various species have shown that males in more dominant roles often produce a LOWER quality and quantity of sperm than those in subordinate roles. This is presumably because the dominant males don't have to compete as much as the subordinates, they get first pick of the females. But this hasn't been tested before, because the animals being studied understandably get annoyed when you try to get between them and their chosen female to get a sample of the semen.

In this case they decided to try again, using chickens. But not your normal chickens, these were Swedish fowl that live in social groups of up to 16 animals. The males form a dominance hierarchy for access to the females. The most dominant males are obviously going to get first crack at the hens, but the hens will often have multiple matings, and sperm competition is intense. Not only do the females go multiple times, the males can ejaculate up to 40 times within a few hours, which often results in quantity over quality, as the sperm quality decreases over time.

They took males of high and low status, and put them through randomized mating trials over several females, ALSO of high and low status. They took the ejaculate and measured the number of sperm, as well as the velocity, or how good their little swimmers were doing.

And the result? Well, you'll have to go read it. There are graphs that are integral to the story, and I don't want to spoil it. Suffice to say, chicken sperm is a lot more interesting than I would have previously guessed.

Image: Some rights reserved by quinn.anya



  1. Not once in my lifetime did i ever think i would find myself analyzing multiple graphs on chicken sperm.

  2. Of course they were Swedish chickens, with their totally relaxed sexual attitudes, being all non-monogamous with each other.

  3. Soory, I have little to no interest in chicken sperm. But the illustration reminds me of walking down an aisle at my local market and being arrested by something I had just walked past; Cock-Flavoured Soup. I wasn’t even certain I had read it and had to walk back several feet.

    I have yet to actually taste said soup but have attached a bag to several different backgrounds of hand-made paper, put them into odd yard-sale frames and given them as gifts.

    Every kitchen needs one.

  4. Such a delectable flavour concept, why stop at soup? :)

    The winner so far: joeygsb…(rimshot, cymbal splash)

  5. Did he really have to say “The most dominant males are obviously going to get first crack…”??

  6. I have a bottle of “Cock” brand fish sauce in my cabinet right now. I NEVER get tired of asking my wife, “Want some cock with dinner?”

  7. In the Guangdong province in China, a local delicacy are chicken testicles.

    I’ve just had some.

    They are white-ish sacs, surprisingly large. The biggest is almost the size of a golf ball. You bite into them, and then presumably into the sperm, which then kind of, of course, oozes into the rest of your mouth.

    Thinking about it now, my stomach is churning a bit and my testicles have withdrawn a bit.

  8. “Suffice to say, chicken sperm is a lot more interesting than I would have previously guessed.”

    You need to get out more, Maggie.

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