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Same-Sex Evolving

May 12, 2012

Much has been made of Obama’s “evolving” position on same-sex marriage. In fact, society as a whole has been “evolving” on sex-associated behaviors over the past century.

But this reminds me of another interesting question: What does biological evolution have to do with same-sex behaviors? In my town, the same people seem to oppose both. For example, the middle school teacher who got fired after eleven years of teaching against evolution also taught (in eighth-grade physics class) against homosexuality. And the same group that came to our church to protest our gay-straight-alliance Halloween party also went to Kenyon College to protest evolution.

If some churches have been slow to accept love between people sharing the same karyotype, let’s remember that science was pretty slow too. Bagemihl recounts two hundred years of scientists failing to discover the normality of same-sex behavior among animals. The unmistakable evidence that same-sex behaviors have evolved amongst all creatures. The story of non-discovery is instructive beyond its subject, in that similar obstacles occur every day in science, in every scientific field, even lowly microbiology–there is prejudice wherever there are people. Still…two hundred years?

So how did this discovery take so long?

  • When two animals were observed to interact, the active one was recorded as male, the passive one as female.
  • When the anatomical sex of the animals was observed, the animals must be making a mistake.
  • Or the observer was mistaken, “disturbed,” or “could not account” for the results.
  • If the observations were submitted for publication, they were rejected.
  • If the observations were published, they had opaque titles such as “On the lowering of moral standards among butterflies.”
  • The published works were not cited.

For some reason, things began to change in the 1980s, when an interest developed in the topic. Why that particular decade? As Spock would say, there is no logical reason why scientists would suddenly become more observant at that time.

But there is certainly an argument for science research to include people of the widest range of backgrounds. The more diverse the array of experiences, the more likely that someone in the research group will come up with a fruitful idea–and someone else will bounce it back. Paradoxically, while science is supposed to be “objective,” it makes a big difference who is doing the research.

9 Comments
  1. fari permalink
    May 14, 2012 3:39 am

    One of my friends has two male hamsters because he thinks that it takes them almost no time to breed a huge family of little furry ones if the normal bond be kept between male and the female hamster.Once he had a party and his hamsters were ,of course, invited.The male hamsters began that ‘forbidden desire’. We all laughed .I was very eager to listen to the comments:While men smiled understandingly and victoriously at each other, some women giggled and tried to hide their embarrassment.Some said that ,” he is so lazy that he made a mistake”, while some other men believed that he was trying to maintain his territory by intimidating the other male hamster by having sex. Hamsters disappeared in a moment in my mind.I was thinking of homosexuality in my country which is a taboo and will remain one because here sex is a tool of the patriarchal regime to control others. It is political and will remain one even when animals are concerned.

  2. May 14, 2012 9:29 am

    “In my country … sex is a tool of the patriarchal regime”
    Not only in your country–In which country is sex *not* used as a tool of control?

    • fari permalink
      May 14, 2012 10:51 am

      You are indeed right and I agree.But you can’t compare here to nowhere else.At least in western countries the matter of controlling via sex is a little moderate, i mean, it is less politically used to repress the individuals.But here, religion has a strong hold on bodies and people indicted for homosexuality are , no doubt, sentenced to death.Sex is not a part of us to decide for here, it is the government that decides for our bodies.I wonder why in U.S Obama’s consent was so necessary on that issue.I thought it was commonsensical in some states, if I am not mistaken. I think all this owes a lot to social feminisms.Even gays are indebted to the movement.Don’t you think so?

  3. heteromeles permalink
    May 14, 2012 6:41 pm

    I liked Bagemihl’s book, except for the hypothesis of biological exuberance.

    My suggestion is that the problem isn’t alternative sexuality (in Bagemihl’s sense), it’s with the theory of sexual selection. The issue with sexual selection specifically is that it’s driven by simple optimality math, that traits are “designed” to maximize the number of offspring, period.

    This makes a bunch of assumptions, such as a constant environment, that are problematic in reality. What if one of those problematic assumptions is that sexual behavior is optimizable to maximize the number of offspring produced?

    It may be that sex is not an “optimizable” trait, if optimum means “maximizing the number of offspring produced. It may be, for instance, that a certain amount of the population falls outside the average, no matter what the average happens to be. It may be that, when evolution provides a desire for sex, it also results in behavior that can be focused on sex surrogates as much on reproduction.

    We don’t know, because we don’t question the fundamental assumptions of selection theory. Because of this, I’m not sure that we can say that homosexuality evolved to do anything it all. It may simply be that sexual behavior inevitably has a diverse set of possibilities, and it’s impossible for evolution (let alone society) to narrow sex down to a single way for every individual to work.

    • May 14, 2012 8:36 pm

      I agree with you in that I’m not sure Bagemihl’s concept of “biological exuberance” is defined clearly enough to be falsifiable.

      I see evidence for many different kinds of functions evolving from same-sex (and different-sex) behaviors that are not directly reproductive, but nonetheless contribute to survival. For example, two male birds plus a female; the male birds interact sexually to strengthen their social bond, so that both contribute food to the shared female. Another example, among the bonobos, genital-contact behaviors appear to have evolved as a “handshake” function that supports social cohesion and diminishes violence.

      In other cases, sex-related behaviors may have evolved into types of play, equivalent to the hill-sliding of penguins or the tree-swinging of monkeys. All types of play help individuals “practice” their awareness of their bodies and surroundings.

    • heteromeles permalink
      May 14, 2012 11:32 pm

      I agree with you, in that there’s potential functionality in many components of sexual behavior. I’d also say that I didn’t express myself very well up there.

      Thing is, things don’t have to be functional to be conserved: Stephen Jay Gould’s article about the female clitoris and male nipples is certainly a good example. One can spend a lot of energy arguing about the evolutionary functionality of either structure, but the simpler explanation is that there are good embryological reasons why both structures exist, and no good functional reason for evolution to get rid of either structure. Any human trait may have similar issues, whether it has to do with sex or not.

      • May 15, 2012 8:50 am

        The functional reason for evolution to “get rid of” nonfunctional structures is that it takes energy to make them–energy that no competing animal can afford to lose. Even the appendix turns out to have a function (sheltering good intestinal bacteria while the bad ones get wiped out). But the thing with functionality is that we scientists lack sufficient imagination (there I do agree with Bagemihl).

        It turns out that for female animals, sexual pleasure has the result of (1) getting them to spread their genes among as many genetically diverse males as possible; (2) confusing the paternity, so that as many males as possible avoid killing their offspring. For male animals, having sensitive organs encourages homosociality in place of killing males in your group–who share a lot of your own genes.

        When we apply this to people, of course it gets hugely controversial. I recall a book that got censored because it referred to the feel of wind blowing across a man’s nipples. And yes BTW men do get breast cancer (there was just an NYT story about it).

        • heteromeles permalink
          May 16, 2012 11:39 am

          I have to disagree, and I’m trying to be sensitive about the disagreement.

          Yes, sex can be pleasurable for females of many species, but then again, many offspring get born out of rape, or out of situations that bring no pleasure at all to the female. And since I’ve seen 17 wild male mallards gang raping a female mallard, I’ll go out on a very small limb and say that rape, even gang rape, isn’t limited to humans or even mammals (mallards pair bond, but gangs of unattached males routinely chase females in the spring, either when the female is alone or when her partner can’t chase them off). Sex and pleasure don’t have to be linked, and in fact, sex and pleasure may drive violence that decreases reproduction (if, say, the female dies from being raped).

          The police data for humans strongly suggest that the most likely suspect in murders is a family member or sex partner, not a stranger, and that sex is a primary motive in many murders. The anthropologists also suggest that this is normal for humans in many different settings. Given this apparent reality (that you’re more likely to be killed by a sex partner, if female, or over sex, if male), one could just as easily make the argument that sexual pleasure leads to decreased life-spans, that (males) decreased life-spans leads to fewer offspring (since males stay fertile through their lives), and that therefore, sexual pleasure is as theoretically maladaptive as it is adaptive, particularly in humans.

          The important thing to realize is that I don’t particularly enjoy making such arguments, and I don’t particularly advocate such arguments either.

          I’d much rather argue that there are problems with many evolutionary arguments, and these problems arise from our assumptions, as much as from the data. I’m comfortable arguing that a structure or behavior may contribute little, if anything, to evolutionary fitness, because said feature may have both positive and negative effects. In many cases, I believe that stories about why anything evolved (say, why male humans have nipples, or in my area of expertise, why many plant species have mycorrhizae) are “just-so” stories of speculation, with little or no data behind them, and that we have to be careful with how we spin them out.

  4. May 16, 2012 4:42 pm

    “Just-so” stories are always a problem in animal behavior. Nevertheless, there is good evidence for all these behaviors. Yes, in some cases animals “force” a sexual encounter, whereas in other cases they beg, barter or trick for it.

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