Snake Clitoris and Boygenius

Female snakes have clitorises too, a new study finds.

The research raises the possibility that the sex lives of snakes are more complicated and diverse than previously understood, researchers report December 14 in Proceedings of the Royal Society B.  First evidence of hemiclitores in snakes, authored by Megan J. Folwell, Kate L. Sanders, Patricia L. R. Brennan and Jenna M. Crowe-Riddell details their investigation of how female genitalia are conspicuously overlooked in comparison to their male counterparts, limiting our understanding of sexual reproduction across vertebrate lineages.

Hemiclitoris

Clitorises are found in a wide range of vertebrate life, from crocodiles to dolphins (SN: 1/10/22). One exception is birds, which lost their clitorises over the course of their evolution. Female snakes appeared to have lost the sex organ too, which was puzzling, since their close lizard relatives possess paired clitorises, called hemiclitorises. Male lizards and snakes have accompanying paired phalli, or hemipenises.

This element of female snakes’ sexual anatomy went unexamined in detail for so long partly because hemiclitorises can be fragile and easy to miss, but also because female genitalia have historically been considered “quite taboo,” says evolutionary biologist Megan Folwell of the University of Adelaide in Australia.

Follow Phillip

@majikphil

“Even in humans, the proper function and significance of the human clitoris was still being discussed in 2006,” she says.

Conflicting accounts of snake hemiclitorises in some scientific papers led Folwell to take a detailed look. She first examined a euthanized female common death adder (Acanthophis antarcticus). “I just started with dissecting the tail and going into it with a really open mind of what I might find,” she says.

She was “pleasantly surprised” to find dual organs within that were completely different from the hemipenises found in male snakes. Also, unlike lizard hemiclitorises, the snake’s couldn’t turn out externally.

To confirm she wasn’t looking at a lump of some other tissue, Folwell and her colleagues carefully examined sections of the organs under a microscope. The team also soaked the tail in iodine, which allowed the soft tissues in the genital region to be seen with greater resolution using X-rays.

A micro-CT scan (left) shows the location of the hemiclitoris in a female common death adder (Acanthophis antarcticus), shown as a small, pink, triangular region at the base of the snake's tail.  A dissected view of this region (right) shows the snake's genital anatomy (CL = the cloaca, a shared chamber for the reproductive organs and elimination of waste, SG = scent glands, HC = hemiclitoris). 
Photo:  M.J. Folwell et al Proceedings of the Royal Society B 2022

Fundamentally Different Tissues

These analyses showed that the tissues were fundamentally different from the male snake’s hemipenises. The female organs were full of primarily collagen rather than muscle fibers running through the structure. Another analysis showed the organs had “heaps of nerves” throughout them, Folwell says, suggesting they probably have substantial tactile sensitivity. Like other species’ clitorises, the snake’s showed a robust blood supply.

The team expanded its study to eight more snake species across four families, revealing a dizzying array of clitoral diversity. For instance, Folwell says, the hemiclitorises of the Mexican cantil viper (Agkistrodon bilineatus) are huge, filling the space of the tail. “Then you see the Ingram’s brown snake, which was so teeny tiny. If you didn’t know what you’re looking for, it definitely could have been missed,” Folwell says.

Some hemiclitorises are thin and lay atop the scent glands, while others are sandwiched between or even a combination of on top and between, she adds.

Snake Evolution

Snakes are thought to have evolved from lizard ancestors. The findings show that, evolutionarily speaking, the snake clitoris “wasn’t lost; it was just changed,” says Diane Kelly, an evolutionary biologist at the University of Massachusetts Amherst, who wasn’t involved with this study.

Folwell and her colleagues think the hemiclitorises may be stimulated during courtship and mating behaviors, such as the twisting together of tails. This may make the female more receptive, encouraging longer and more frequent mating and enhancing the chances of fertilization.

“It’s been often believed that, in snakes, it’s been all about coercion, and all about the male driving mating,” Folwell says. “It may be a little bit closer toward seduction in some species.”

Going forward, Folwell wants to look further into how nerves in hemiclitorises are involved in any touch sensitivity and function during mating.

Kelly notes that comparing hemipenises and hemiclitorises of the same species could help get an idea of the organs’ function in snakes, and potentially reveal any back-and-forth evolution between males and females.

“It’s 2022, and here’s a brand-new anatomical finding in a really common animal,” Kelly says. “There’s a lot of anatomy that we still don’t know yet.”

About Australian Common Death Adders

You could never mistake a death adder for any other snake—that is, if you see it in the first place. These reptiles are supreme masters of disguise, which is essential to their whole way of life. Unlike most other venomous snakes, which hunt to locate their prey, death adders are ambush predators that wait unseen for prey to pass by.

Their stocky bodies don’t look as if they could move fast, but when they sense potential prey close by they react with lightning speed to inflict a highly venomous bite. No other venomous Australian snake strikes as fast.

As well as having that characteristic short stumpy body shape, adders also have a distinctive arrow-shaped head, narrow neck, and a thin tail with a curved tip that they shake around near their mouth like a worm to lure potential prey close.

This species, the common death adder, is one of seven known species of death adders occurring in Australia. It’s found in all mainland states and territories in a wide variety of habitats – from rainforest, open woodland and scrubland to coastal heathland. It prefers locations with a lot of leaf litter or forest debris in which it can hide away.

The venom of all death adders is potentially fatal to humans and, before an antivenom was developed in the late 1950s, more than half of people bitten would die. Last century there were at least five recorded human deaths attributed to death adders. There have been none this century, so far.

101 toxic cane toads (Rhinella marina) released in Australia in 1935 turned into 2+ billion cane toads today.  They are deadly to snakes, goanna lizards, and other native species susceptible to their poison.

Death Adders Threatened by Exotic Species

Death adders are threatened by a loss of habitat, but more of a threat is the introduced and highly invasive cane toad. Young death adders are eaten by these toads. And adult death adders are fatally poisoned by the toxic glands in cane toad skin when they eat these amphibians.

Rolling Stone says boygenius are the supergroup we need.  From reading their cover story I'm not convinced.

"They are thinking about promoting The Record with press conferences in major cities, partly to avoid an avalanche of interview, but also because they think it sounds like a good time."  

Seems like kind of a slight to fans who might want to see them in smaller towns.  Right?

They talk about touring this year including a slot at Coachella but when they get into details of their plans it kinda falls apart for me.  Read on.