ScienceDaily (June 17, 2009) — Same-sex behavior is a nearly universal phenomenon in the animal kingdom, common across species, from worms to frogs to birds, concludes a new review of existing research.

"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, the first author of the review paper and a postdoctoral researcher in the Department of Biology at UC Riverside.

There is a caveat, however. The review also reports that same-sex behaviors are not the same across species, and that researchers may be calling qualitatively different phenomena by the same name.