Why Are So Many Animals Homosexual? By Brandon Keim

 

( Dr. A.S. Amin will be giving a talk in April on ” Is Reproductive Drive responsible for shaping our culture, society and even religions including Islam?” The lecture is based on his recently published book ,”Conflicts Of Fitness” Islam, America and Evolutionary Psychology.”The article below may add an other dimension to that interesting talk. F. Sheikh) 

Few creatures can boast of devotions so deep as greylag geese. Most are monogamous; many spend their decade-long adult lives with the same goose, side-by-side in constant communication, taking another partner only if the first should die. It’s a remarkable degree of fidelity, and it includes relationships of a sort that some humans consider unnatural.

Quite a few greylags, you see, are gay. As many as 20 percent by some accounts. That number might be high: It includes those males who first take a male partner but later pair with a female, or whose first bond is with a female, but after she dies, takes up with a gander. That said, plenty more are exclusively homosexual from beginning to end.

Which raises the question: Why?

That’s puzzled quite a few scientists—those who study greylag geese and also the hundreds of other animal species in which homosexuality is, confoundingly, found. After all, evolution is driven by reproduction. In animals, that requires—self-cloning reptiles not withstanding—the union of opposite sexes. Through a reproductive-success lens, homosexuality would appear counterproductive, if not downright aberrant. It’s certainly not aberrant, though, considering its ubiquity.

So to frame the question a bit more scientifically: Is homosexuality, in the words of Kurt Kotrschal, a behavioral biologist at the University of Vienna, “preserved because there was some stabilizing selection, or is it an unavoidable product of brain development?” Was homosexuality useful in evolution’s grand pageant—or just something that popped up and stuck around?

Researchers don’t have a simple answer. Not even Kotrschal, who has studied greylag geese for decades, working at a research station named for the late, great zoologist Konrad Lorenz, whose most famous studies involved the same bird.

Lorenz himself considered homosexuality useful. “We can be sure that every one of these instincts has a very special survival value,” he wrote in 1963, describing how pairs of partnered males frequently attained social superiority in goose colonies. Their superiority in turn attracted lone females with whom one gander might briefly copulate, before returning his attention to the true object of his affections, wrote Lorenz. By that light, homosexuality serves to promote reproduction. That is one possible explanation; there are plenty more

Other scientists have suggested that homosexual couples might perform some important social duty, such as helping to raise other couples’ goslings or guarding colonies from predators. That would help same-sex couples’ relatives rather than themselves, a well-known evolutionary strategy called kin selection, illustrated most dramatically by honeybee workers who forgo reproduction and sacrifice themselves for their hive’s greater good.

Kotrschal himself doesn’t think this likely—there isn’t much evidence for obvious, give-the-nephews-a-wing-up helpfulness in greylag geese, though it could manifest in other, subtler ways. Perhaps homosexuality is the inevitable byproduct of emotional systems that fuel mate pairing: You can’t have heterosexual love without some overflow.

http://nautil.us/blog/why-are-so-many-animals-homosexual

posted by F.sheikh