Snakes have clitorises, and scientists finally found them

As It Happens6:38Snakes have clitorises, and scientists finally found them

When Megan Folwell discovered a clitoris on a snake she was dissecting, she says she felt "like a kid in a candy store."

"[I was] just kind of jumping up and down, which is terrible to do with a scalpel," the biologist told As It Happens host Nil Köksal. 

Folwell, a PhD candidate at Australia's University of Adelaide, can now claim the distinct honour of being — as far as she knows — the first scientist to discover a snake's clitoris.

Since her eureka moment, she and her colleagues have documented clitorises on nine different species of snakes. Their findings were published in the Proceedings of the Royal Society B Journal . 

Why did it take so long?

So why did it take so long for someone to find a snake's clitoris? 

"Initially I was really surprised that it hadn't [been found]," Folwell said. "And then I realized that this is a common occurrence across all animals where female genitalia is just massively understudied."

Folwell was studying the reproductive anatomy of female snakes, but found there wasn't a lot of scientific literature on the topic. 

Meanwhile, she found hundreds of papers about male snake genitalia, which consists of two penis-like appendages known as hemipenes.

"They've been quite intensively studied — really all of the tiny little details," Folwell said. "Which is why I was so surprised that I couldn't find anything on the female side."

So she went straight to the source and began dissecting snakes from a collection at the South Australian Museum. She was investigating a death adder snake when she found the sex organ in question — or more accurately, two of them. 

"I saw this double-clitoris structure," she said.

Snake clitorises, it turns out, come in pairs called hemiclitores, and they are similar to those found on several other species of reptiles. They're located just beneath the cloaca, a single all-purpose reproductive, urinary and digestive orifice.

"It was completely different to the scent glands. It was completely different to male hemipenes. And I could distinguish it between the surrounding connective tissue, which was a big moment for me," Folwell said.

Folwell took her findings to her colleagues, including Patricia Brennan, a biologist who studies animal genital morphology at Mount Holyoke College in Massachusetts. 

"I almost fell off my chair," Brennan, who is a co-author on the study, told the Atlantic.

Brennan has extensively studied the genitals of many animals. She has even personally sought out the snake clitoris, to no avail. 

Folwell says that's not necessarily surprising. She and her colleagues found that the clitoris structure varies between snake species, and often they're "quite fragile and really small."

In fact, she suspects some scientists have, indeed, come across them before, but mislabelled them as underdeveloped hemipenes or scent glands. 

Are they for pleasure?

So what does a snake do with its double-clitoris? Folwell says they'll have to do more studying to know for sure — both of the structure itself, and of snake mating behaviour.

But they already have some clues. 

"It had nerve fibres and nerve bundles throughout the whole thing, which kind of indicates that it potentially has a role in tactile sensitivity," Folwell said. "So it potentially gets stimulated before or during mating."

This could change the prevailing narrative about snake sex, says co-author Kate Sanders, a University of Adelaide biologist.

"Snake mating is often thought to involve coercion of the female — not seduction," Sanders said in a press release.

Although the scientists can't be sure, there is some indication that male snakes know exactly where the clitoris is and what it's for. 

Folwell says males have been documented wrapping themselves around a female's tail — where the clitoris is located — and pulsing.

"I suspect that this is potentially a behaviour that is stimulating the clitoris and, you know, influencing some other signals along the way to encourage her to want to mate or improve reproductive success," she said.

Ecologist Jonathan Balcombe isn't surprised by the findings. He's written extensively about animal sexual pleasure in his 2006 book Pleasurable Kingdom: Animals and the Nature of Feeling Good.

"Reproduction is obviously vital for snakes to be successful, so we may expect strong selection pressure for behaviours and anatomy that facilitate the process," he said in an email to CBC.

The study notes that clitoral stimulation in animals can be beneficial to reproduction. It may generate lubrication for example, or relax the vaginal opening, or prepare the reproductive tract to receive sperm.

"While animal pleasure remains a relatively neglected topic 15 years after I wrote a book about it, it doesn't take much imagination to appreciate its utility in animals' lives," Balcombe said.