Rabbits may hold key to mystery of female orgasm
Scientists have spent years trying to see if the female orgasm serves a purpose beyond sexual pleasure, given that, unlike the male orgasm, it has nothing to do with reproduction.
According to a new study involving rabbits, it could indeed have a biological function: ovulation.
The research, published in ‘Proceedings of the National Academy of Sciences’, supports the idea that female orgasms might have originated from a reflex that prompts some female mammals to release eggs during intercourse.
Researchers analysed the number of eggs released by 21rabbits after they’d had sex with a male rabbit, Frank.
Some of the rabbits were put on antidepressants known to reduce the capacity for female orgasms, while others were not. The scientists found that the rabbits who were given antidepressants, and therefore would have had fewer orgasms or none at all, released 30% fewer eggs compared to the rabbits that were not.
The findings fit the authors’ theory that rabbits need to orgasm in order to ovulate, something that similar studies have also suggested in other mammals.
In 2016, the same team looked at 41 different species of mammal, including camels, cats and koalas, and found that15 of them also had the same reflex, whereby ovulation is triggered by copulation.
Of course, the same effect is no longer true for humans as they ovulate spontaneously. But the researchers think that it could have been true for our mammalian ancestors.
The authors write: “The existence of female orgasm is intriguing for two reasons: On the one hand, female orgasm is not necessary for female reproductive success, and on the other hand, this neuro-endocrine reflex is too complex to be an evolutionary accident. This led to many proposed evolutionary explanations, most of which have little empirical support.”
Citing their 2016 study, the authors said they previously suggested that female orgasm “uses a mechanism that originated for inducing ovulation during copulation”, which it says is a mechanism that still exists in many animals but lost its role in others. “Here we provide experimental evidence, strengthening the likelihood that female orgasm evolved from copulation-induced ovulation,” the authors say.