From The Economist magazine, June 29th 2010
WHAT is taught in a country’s schools reveals much about the national psyche. The Norwegian curriculum requires that all 14-year-olds learn about homosexuality. Assisting with this education, the National History Museum at the University of Oslo has just opened an exhibition of gay animals.
“Against Nature?” does not tell zoologists anything new. Homosexuality has been recorded in some 1,500 species so far, and been well documented in about a third of these cases; it has been known since the time of Aristotle, who thought he witnessed two male hyenas having sex with one another. But the exhibition’s purpose is not to educate zoologists. It is to persuade the public that, as there are gay whales and worms, gay humans do not disturb the natural order.
Aside from illustrating homosexuality among an extraordinary variety of creatures, the exhibition shows how sexual stimulation can vary when, at first blush, the mechanical details of how this might work are not obvious to people attempting to draw analogies from their own anatomies. Male Amazonian river dolphins, for example, penetrate the blowholes of other males; female bottlenose dolphins use their snouts as dildos on other females.
Why this behaviour might be favoured by natural selection, though, is a difficult question to answer. In an attempt to do so, the exhibition picks on gay flamingos. Two males raising a chick after one of them had a one-night stand (of sorts) with a female are able to hold a larger territory than male-female partnerships. This suggests a chick with two dads could get more food and therefore have a better chance of survival. But explanations are harder when gay animals (such as some humans and, apparently, some killer whales) never try to mate with the opposite sex.
Theoretically, there are several possible ways homosexuality could have evolved. One is that homosexuals assist in the upbringing of their relatives so much that they pass on more of their genes this way than by having children themselves. Another suggestion assumes the genes that confer homosexuality in males are different from those that confer it in females. For the theory to work, these genes would have to confer some extra reproductive advantage to their straight carriers. This way, genes that increase the chances of one sex surviving and reproducing might not be discarded through the generations even though they inhibit making babies when they occur in the opposite sex. But testing these theories is hard, so nobody knows if they are true.
Taking lessons on sexuality from the birds and the bees itself requires first accepting something not taught ubiquitously outside Norway—that evolution occurs by natural selection.
Fine the original article right here: https://learnmore.economist.com/story/58d26bae30959d5230d356b8#!/page/1/1