Is Same-Sex Behavior Natural in the Animal Kingdom?
Sun, April 18, 2021

Is Same-Sex Behavior Natural in the Animal Kingdom?

Earlier this year, a gay penguin couple at a German zoo, Skipper and Ping, adopted an egg. The zookeepers decided to give them a chance at parenthood after seeing their bond / Photo by: Anton Rodionov via Shutterstock

 

Earlier this year, a gay penguin couple at a German zoo, Skipper and Ping, adopted an egg. The zookeepers decided to give them a chance at parenthood after seeing their bond, which they have had ever since they arrived at the zoo in April. This is the first time that the two male king penguins have been allowed to parent a chick of their own. However, this is not the first time that such a situation has happened. In fact, Skipper and Ping join a storied lineup of gay penguin parents. 

CNN, an American news-based pay television channel owned by AT&T's WarnerMedia, reported that longtime penguin lovers Ronnie and Reggie from the ZSL London Zoo were able to hatch an abandoned egg in 2015. Last January, the keepers at Sydney's Sea Life Aquarium in Australia welcomed a baby gentoo penguin, Sphengic, who was named after her adoptive dads, Sphen and Magic. 

The most popular gay penguins, who inspired an award-winning children’s book titled “And Tango Makes Three,” are Silo and Roy, who found love at the Central Park Zoo. They hatched and raised a chick named Tango during the same year. However, homosexual coupling is not limited to penguins. A 2009 study of same-sex animal behavior revealed that there are at least 1,500 species observed to partner up with another member of their sex. 

For instance, studies show that gay behavior accounts for more than 90% of all observed sexual activity in giraffes. According to DW, a German state-owned public international broadcaster, both female and male bottlenose dolphins display homosexual behavior. Homosexual activities in their species occur with about the same frequency as heterosexual play. Also, homosexual activity between male bison is reported to be more common than heterosexual copulation because female bison only mate with bulls about once a year. As a result, more than 50% of mounting in young bison males happens among the same gender.

The 1999 book titled “Biological Exuberance” written by Bruce Bagemihl was the turning point for many scientists to study homosexuality in the animal kingdom. In the book, Bagemihl listed many examples of homosexual behaviors from a lot of species. However, some still think that homosexual behavior among animals is rare. Even scientists have been baffled by this question for many decades. 

Why Does Homosexual Behavior in the Animal Kingdom Matter?

Despite numerous examples of homosexual behavior in the animal kingdom, it still seems to be a rarity partly because only a handful have made it a habitual part of their lives. Following Charles Darwin’s theory of evolution by natural selection, it implies that genes have to be passed onto the next generation, or else, they will die out. Since homosexual pairs can’t reproduce a child of their own, homosexuality ought to quickly die out.

However, homosexual behavior isn’t an occasional or isolated event for some animals but a regular thing. "There's got to be a reason for this. There is no way the behavior can be evolutionarily irrelevant,” Paul Vasey, a researcher from the University of Lethbridge in Alberta, Canada, said. Up until now, little is known about the evolutionary consequences of such behavior. The fact remains that thousands of animals exhibit same-sex behavior, including same-sex courtship, pair-bonding, and copulation. 

According to Cell Press, an online journal that provides a platform for the communication of strong, engaging science to the scientific community and beyond, scientists need to study the phenomenon in a broader framework. This can lead to a better understanding of homosexual behavior and the processes that shape their reproductive behavior, social interactions, and even morphology. 

Despite numerous examples of homosexual behavior in the animal kingdom, it still seems to be a rarity partly because only a handful have made it a habitual part of their lives / Photo by: Javier Brosch via Shutterstock

 

Exploring the Evolution of Animal Homosexuality

A recent study conducted by researchers from the Yale School of Forestry & Environmental Studies stated that scientists have been looking at same-sex sexual behavior all wrong.

One of the main questions is why same-sex behavior is so persistent in the animal kingdom when they offer no opportunity to produce offspring. A 2008 study suggested that homosexual behavior may have evolved independently in different animals for adaptive reasons. "It could be a way that you strengthen bonds — that's one hypothesis. Another is that it could be practice for heterosexual sex. Bottlenose dolphin calves mount each other a lot. That might benefit them later on,” Janet Mann, a biologist at Georgetown University, said. 

However, the recent study published in Nature Ecology & Evolution suggested that homosexual behavior may actually have been part of the original, ancestral condition in animals. According to Phys.org, an internet news portal that provides the latest news on science, same-sex behavior is part of the original fabric of animal evolution and didn’t evolve independently. The researchers debunked the notion that this behavior is costly for animals. Evolutionary biologists stated they call it “neutral” since it has neither positive nor negative effects on the animal kingdom. Thus, it persists because there's no reason for natural selection to weed it out.

One of the main questions is why same-sex behavior is so persistent in the animal kingdom when they offer no opportunity to produce offspring / Photo by: Maryke Scheun via Shutterstock

 

The findings of the study also showed that homosexual behavior among animals can be beneficial to them from a natural selection perspective because individuals are more likely to mate with more partners. Many species try to mate with more than one animal. "So, if you're too picky in targeting what you think is the opposite sex, you just mate with fewer individuals. On the other hand, if you're less picky and engage in both SSB and DSB, you can mate with more individuals in general, including individuals of a different sex,” co-author Max Lambert, a postdoctoral fellow at the University of California-Berkeley's Departmental of Environmental Science, explained. 

One of the main reasons why scientists tend to shy away from studying this topic is because homosexuality has been historically judged as abnormal. This is why a lot of research only confirms pre-existing assumptions about same-sex behavior in the animal kingdom.