Humans aren’t the only species who can get it on with both the same and opposite sex. The entire animal kingdom is one giant cesspool of sexuality. But with all the theories of why some of us are (nature! nurture! God wants us having hotter sex!), it still doesn’t explain one notion: If being gay doesn’t produce offspring, shouldn’t evolution have phased out homosexuality some time ago?
What a terrible universe that would’ve been!
Researchers at the University of California at Riverside just completed a year-long study, and came up with at least five reasons to explain why mammals (dolphins), birds (penguins and albatrosses), reptiles (bearded dragon), fish (grayling), and even insects (fruit flies) have no problem doing the nasty with their own sex. But before we get to the theories, know this: They all revolve around the notion that, according to Time, “same-sex sexual activity is either an accident or a quirky genetic method of helping males impregnate females. Which raises the evolutionary question of why men and women who are exclusive gay and lesbian exist. One answer is that exclusive gays and lesbians are a relatively new creation: the concept of exclusive homosexuality barely existed before modernity; even a century ago, most same-sex-attracted men and women got married and had kids.”
1. The boys-in-the-locker-room theory. Any guy who played sports in high school knows that homoerotic jokes and towel-snapping are an underlying part of the subculture. Similarly, male bottlenose dolphins use same-sex sexual behavior to maintain and strengthen their social relationships — although dolphins are far more explicit about their homosexual play, regularly mounting one another and (hide the kids’ ears here) sticking their noses into certain boy-dolphin parts. (Very regularly: roughly half of male dolphin sex occurs with other males.) Among bonobos, same-sex sexual behavior is also thought to ease social tension and facilitate reconciliation. And among garter snakes, male-on-male contact may allow some solitary males to thermoregulate and, therefore, survive.
2. The emasculation theory. Some male animals might mount other males as a way of denying them access to the ladies. For instance, as the Journal of Natural History noted in 2006, male dung flies often must compete violently to impregnate females. In those situations, “the most sensible strategy for beating a competitor in the race to an arriving female would be to mount him and remain in situ for as long as possible.” Then, when the lady dung fly finally sails by, the aggressor male can pull himself out from the dominated male and — because he is on top — get above to the female faster.
3. The “oops” theory. Among insects, same-sex sexual behavior is usually a case of mistaken identity. Male fruit flies, for instance, may romance other males because they lack a gene that enables them to distinguish between sexes. Even more surprising, male toads can’t tell the difference between girl toads and boy toads, so males will routinely embrace other males, although the subordinate ones are equipped with a call that quickly results in the dominant male releasing. In other species, the “straight” males get tricked by other wily straight males who dress in animal drag: male goodeid fish, for instance, sometimes have a black spot that resembles a spot that females get when pregnant. Dominant males then court them rather than fight with them. While the dominant guys are busy courting the subordinate, ladylike fish, the latter are able to “sneak copulations with females,” as Bailey and Zuk write. I’m going to dub this the Hugh Grant Theory: it’s not always the most masculine guy who gets the most girls.
4. The let’s-see-how-this-thing-works theory. Younger animals (particularly males, and including humans) sometimes engage in same-sex sexual behavior as practice, which may improve their reproductive success when they are ready for a heterosexual relationship later. Fruit flies who experiment with other members of the same sex as youngsters may have more baby fruit flies later on than those who don’t experiment.
5. The two-plus-one theory. Among flour beetles, males routinely force themselves on other males. According to Bailey and Zuk, there’s some evidence that sperm deposited during this male beetle rape is sometimes transferred to a female later on, increasing the chances that she will have offspring.
Now, who can’t relate to all of these?
Now it’s time to figure out which one of these theories explains why, when we were a wee boy and visiting a friend’s house, his two male dogs kept going at it.