It's possible that scientists have been examining same-sex sexual behavior in animals incorrectly.
A study published Monday in the journal Nature Ecology & Evolution posits that researchers should be asking "why not?" instead of why in terms of animals engaging in same-sex behavior (SSB).
"Usually, when evolutionary biologists see a trait that's really widespread across evolutionary lineages, we at least consider the idea that the trait is ancestral and was preserved in all those lineages," Julia Monk, a doctoral candidate at Yale University, who co-authored the new research, told Live Science. "So why hadn't people considered that hypothesis for SSB?"
According to Live Science, researchers have seen same-sex sexual behavior as posing a conflict: Scientists have wondered why animals would spend time doing something sexual that doesn't involve passing on their genes to future generations. Still, same-sex sexual behavior has been seen in 1,500 species.
The scientists make a point in their study of not using words like "gay" or "straight" or any term that humans use to describe sexuality.
The reearchers hypothesize that the oldest sexually reproducing animals tried to mate with any or all members of their species, regardless of sex.
According to Live Science, the authors argue that this path could've made sense as a way to compensate for the fact that distinguishing traits between males and females are "energetically costly" to evolve.
Caitlin McDonough, a study co-author and doctoral candidate at Syracuse University, said the new hypothesis undercuts old assumptions about same-sex behavior, including the notion that it is costly in comparison with different-sex behavior.
"You really need to go through those assumptions and test the costs and benefits of both behaviors in a system," McDonough said.
Monk said that if same-sex behaviors go back to the roots of animal evolution, the fact that these behaviors are so common today makes sense.