Examples of same-sex behavior can be found in almost all species in the animal kingdom — from worms to frogs to birds — making the practice nearly universal among animals, according to a new review of research on the topic.
“It’s clear that same-sex sexual behavior extends far beyond the well-known examples that dominate both the scientific and popular literature: for example, bonobos, dolphins, penguins and fruit flies,” said Nathan Bailey, a postdoctoral researcher at the University of California, Riverside.
Same-sex behaviors in different species are not all equivalent, the review finds. For instance, male fruit flies sometimes court other male flies, but this behavior is due to a missing gene that gives the flies the ability to distinguish between sexes, said Bailey, a co-author of the review. “That is very different from male bottlenose dolphins, who engage in same-sex interactions to facilitate group bonding, or female Laysan Albatross that can remain pair-bonded for life,” he added.