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Guest Blog

Commentary invited by editors of Scientific American

Getting to Know Whale Vaginas in 7 Steps


It’s not easy to study a whale vagina. But it is necessary.

Right now, penises get far more attention than vaginas in the science world. (It’s also apparent in the museum scene, too—sadly, today, there’s no vagina equivalent to rival the Icelandic Phallocological Museum). Surprisingly, the research imbalance is likely due to longstanding gender stereotypes and not perhaps the more common assumption that it’s just easier to observe and study penises than vaginas.

Credit: Gregory "Greg" Smith via Flickr

As science journalist Ed Yong recently noted, this is a troublesome trend. First, a gender bias in research subjects skews our basic understanding of sexual selection and evolution; as a result of a preference for sperm and penis studies over female genital investigations, we have underestimated the role of female choice and selection in influencing the course of evolution.

Second, and on a more practical level: without basic understanding of reproductive strategy, we can’t effectively manage natural populations. If the goal of fisheries management is to optimize the growth potential of wild populations, we’ve got to know the basics about what makes a population grow (successful sex and reproduction) and shrink (mortality).

This is especially important when it comes to endangered or vulnerable species, like marine mammals; we need to know how, when, and where they reproduce in order to accurately predict how our actions (fishing, coastal development, pollution) may affect a species’ survival. To do this requires understanding both sides of the mating equation.

But, let’s be honest – all gender biases aside, studying vaginas can be a formidable challenge, especially in ocean-roaming species such as whales and dolphins. Just consider the logistics. Their hosts live far offshore where we can’t see them and even when we do find them it’s tough to get close and challenging to stay long enough to witness them in the act. And while we can catch glimpses of dolphin penises ready for action, it is far more difficult to figure out what is happening up in their vaginas. So how do we do it?

Sarah Mesnick following sperm whales in the Gulf of California in 2009. (Courtesy of Sarah Mesnick)

I turned to my friend and colleague, Dr. Sarah Mesnick, who works with NOAA’s Southwest Fisheries Science Center and the Scripps Institution of Oceanography at UC San Diego, for answers. She works on reproduction in marine mammals. If anyone can talk animal vagina science, it’s her. So I asked her point blank: How do you study a whale vagina? And then I crafted the following step-by-step guide. For those of you interested in the nitty-gritty of animal sex research, it’s a roadmap for getting intimate with some of the largest, most convoluted vaginas on the planet. You’re welcome.

Step 1: Leverage Victorians’ obsession with sea creatures

They might have appeared prude, but back in the day, naturalists didn’t shy away from the chance to get up close and personal with these mysterious mega “fish.” When a marine mammal washed up on shore, the local scientist would go down, do a dissection, and take copious notes, including sketching and describing in great detail the reproductive bits of the animal.

Meek, A. 1918. The Reproductive Organs of Cetacea. J Anat. 52 (Pt 2): 186–210.

Mesnick notes, “It’s rare to do this today. Remember a few months ago, when they discovered that new knee ligament? We think we know all there is to know about human anatomy, but we don't. But back in the 19th century they knew they didn’t know it all, so they wrote really detailed descriptions.” Mesnick uses these old papers like treasure maps. They lead one through what turns out to be an astonishingly diverse assortment of female reproductive structures.

Hunter, J. and Banks. J. 1787. Observations on the Structure and Oeconomy of Whales. Phil. Trans. R. Soc. Lond. 77: 371-450.

Step 2: Ask a stranger to FedEx a whale vagina

Dusty old papers can only get one so far, so you’ve got to really get your hands dirty. And that means dissections. But where do you get specimens of a whale or dolphin, especially since they are protected? Across the U.S. and in other countries, there are standardized protocols for dealing with stranded marine mammals that wash up on shore. When one strands and dies, scientists want to know why, so they conduct a necropsy (an animal autopsy).

Mesnick has a freezer full of whale reproductive tracts sent from all over. “We reach out to people who find these animals and ask them to save the reproductive tract and send it to us. I collaborate with a graduate student, Dara Orbach from Texas A&M, who is also collecting reproductive tracts from her contacts. Just this week, we received a box of tracts that was shipped to us from New Zealand.” And when she says “tract” she means the whole kit and caboodle, from the clitoris (yup, female whales and dolphins have a clitoris!), up and around the vagina, uterus and the uterine horns (aka fallopian tubes in women).

Meek, A. 1918. The Reproductive Organs of Cetacea. J Anat. 52 (Pt 2): 186–210.

She admits it’s an awkward conversation, even among scientists. But it works. As long as there are no mail mix-ups:

“Awesome! My new microscope arrived… ?? What the @#$%?”

Step 3: Make use of bycatch

Besides the stranding network, marine mammals accidently caught by commercial fishing boats can also be collected by fisheries observers. These specimens are often housed in life history collections stored at museums or the Southwest Fisheries Science Center, some going back decades.

Step 4: Have a back up generator

This one is mine. It’s well known that decomposing whale has a stench like no other. Can you imagine what that room would smell like if the freezers failed? Of course, there would also be the loss of invaluable research specimens. So, power source – back it up.

Step 5: Assemble an A-team that includes expert drivers

Veterinarians and others who work in medical schools and have experience with live animals are key collaborators on Mesnick’s team. “These guys are really good at driving tiny cameras around the reproductive tracts of marine mammals,” she says, and can help visualize the 3D structure of the tracts using techniques such as CT scans and endoscopy.

Step 6: Grab the grill tongs

Whale and dolphin vaginas come in all sizes. Mesnick currently works on ones from eight to ten inches up to two feet. “You can easily fit your whole arm up in there,” says Mesnick. And she has. All I can think of is what the hell do you use for a speculum Then, I learn this: the big baleen whales can be over 100 feet in length, so their reproductive tracts likely wind for several feet. That’s a vagina you could walk through. Mesnick notes, “I haven’t gotten to work on one of those yet, but I can’t wait to!”

Step 7: Bring your GPS

Mesnick is finding that, unlike most mammals, whales and dolphins have remarkably complex and convoluted vaginas. Normally, a mammalian vagina is a simple tube or cavity, with the cervix at the far end. But this is not so in some whales and dolphins, where a series of flaps, folds, blind alleys and funnels presents a dizzying maze for sperm to negotiate. “It’s a gauntlet. Our very first one, when we opened it up, there were so many structures in there we could not figure out how a sperm would be able to swim from one end to the other,” Mesnick says.

They found that some species have multiple funnels. Others have flaps or multiple folds. These structures were first described as a “pseudocervix” because they superficially looked like the true cervix. Not every species looks this complicated; other species have far less ornamentation.

The diversity is one of the reasons these structures are so hard to map: there are no consistent reference points to know where you are once you are exploring them – each vagina looks different. As Mesnick notes, “We’re getting to the point now that if we open a tract up we can tell you the species, just by looking at the structures in the vagina.” Now I’m thinking vagina-based species identification books.

There are several theories on why these structures exist, including that the twists and turns are designed to help keep water (which is fatal to sperm) out of the tract. But as she continues to compare more and more internal sex structures of dolphins and whales, Mesnick thinks there might be more to it: “The simple question is, if all cetacean species mate in the water—which they do—and the flaps and funnels were just to keep water out, then why is there such diversity among species?”

Good question. And you know she has a good answer. But she’s keeping it to herself for now, until she finishes a few more dissections, just to see that her theories hold up. I did get a hint: it likely has to do with cetaceans’ mating system. Which means whale vaginas can tell us a whole lot more than just how big a whale penis is.

Hunter, J. and Banks. J. 1787. Observations on the Structure and Oeconomy of Whales. Phil. Trans. R. Soc. Lond. 77: 371-450.

Lastly, and it’s not an official step to knowing whale vaginas, but it is critical to understanding whale reproduction: you’ve got to check out the male apparatus, too. Mesnick stresses the point: “A whole other side of my research is looking at the male anatomy and this is where we get some of our other predictions about the form and function of the female anatomy… So yes, I look at both sexes, because this is how we get the most complete understanding of the reproductive strategies of the sexes.”

You can expect a blog soon on the male side of the equation. I wouldn’t want to be biased, after all. I’ll be continuing to follow Mesnick’s research as she and colleagues wrap up the mystery of meandering whale vaginas over the next year. Stay tuned for updates.

And apologies to those of you who thought this post was going to be a tourist’s guide to San Diego. I hope you found it educational nevertheless.

The views expressed are those of the author and are not necessarily those of Scientific American.

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