An article in this month’s Seed magazine argues convincingly that same-sex sexuality is not a mere genetic aberration, as Darwin believed, but a natural, and probably necessary, fact of life in the animal kingdom. (Darwin’s theory of sexual selection, in short, states that males compete to procreate with as many females as possible. Females are reluctant; males are horny. Evolutionary success is defined by the quality of offspring. So any aberration from this relentless drive to procreate is a waste of precious fluids.)

Now this:

Giraffes have all-male orgies. So do bottlenose dolphins, killer whales, gray whales, and West Indian manatees. Japanese macaques, on the other hand, are ardent lesbians; the females enthusiastically mount each other. Bonobos, one of our closest primate relatives, are similar, except that their lesbian sexual encounters occur every two hours. Male bonobos engage in “penis fencing,” which leads, surprisingly enough, to ejaculation. They also give each other genital massages.

As this list of activities suggests, having homosexual sex is the biological equivalent of apple pie: Everybody likes it. At last count, over 450 different vertebrate species could be beheaded in Saudi Arabia. You name it, there’s a vertebrate out there that does it. Nevertheless, most biologists continue to regard homosexuality as a sexual outlier.

Read the full story here.