Asher Elbein, "Seeking a New Lens to Study Same-Sex Behavior in Animals," New York Times, November 26, 2019.

A team of researchers say that science has relied on a human heterosexual baseline and made faulty assumptions about sexual activity in the animal kingdom.

Male field crickets perform mating songs and dances for each other. Female Japanese macaque monkeys pair off into temporary but exclusive sexual partnerships. Pairs of male box crabs occasionally indulge in days-long marathon sex sessions.

Comparable arrangements can be found in damselflies, Humboldt squid, garter snakes, penguins and cattle. In fact over 1,500 species across most major animal families have been observed engaging in sexual activity with individuals of the same sex. But the origins of such same-sex sexual behavior have long puzzled evolutionary biologists. How could this behavior evolve and persist in so many lineages, even when it doesn’t directly aid reproduction?

That very question may be the wrong one to ask, a group of researchers argue in a study published last week in Nature Ecology and Evolution, seeking to flip the underlying assumptions of a whole wing of biology.

“The expectation has been that same-sex sexual behavior evolved in different species independently, against this default background of heterosexual sex,” says Ambika Kamath, a researcher at the University of California, Berkeley, and co-author on the study. “And what we’re saying is that baseline isn’t necessarily the right baseline.”

See the rest of the New York Times article at https://www.nytimes.com/2019/11/26/science/same-sex-behavior-animals.html