David Goggins
Former Navy Seal
Career Development
Bryan Cranston
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Chris Hadfield
Retired Canadian Astronaut & Author
from the world's big
Start Learning

Sexual evolution: What duck mating reveals about relationships, social movements, and politics

Evolution proves that sexual predators are jerks.

Richard Prum: According to aesthetic evolution, animals are agents in their own evolution; that is, through their choices they end up shaping their own species.

One of the implications of this idea is a new perspective on what happens when mate choice is infringed or violated by sexual violence or by coercion in animal species.

One prominent example of this, from our own research, is on duck sex.

Ducks are unusual among birds in having both a typical mate choice situation—where male and females pair up on the basis of display and preferences—and simultaneously other individuals that force copulations on female ducks as they approach reproduction.

So what that means is that as the eggs are being laid, females have to defend themselves from forced copulations by males. Now “forced copulation” is the word that biologists use now, but for over a century biologists used the word “rape” in biology.

Now that was abandoned back in the 1970s in response to the feminist movement and Susan Brownmiller and her work Against Our Will, proposing and articulating a specifically social context for rape in humans.

This led to the creation of a euphemism, “forced copulation,” in biology.

Unfortunately, articulating sexual violence in the animal world with these euphemistic terms has led to scientists losing track of the fact that forced copulation is against the will of the ducks.

And by taking the aesthetic perspective and trying to understand what it is that individual females—in this case ducks—want we have arrived at a new perspective on what it means when they don’t get what they want. So in some ways using socially sensitive euphemisms has led to imprecision or fuzziness in the science.

In the case of duck sex what we find is that males can force themselves on females because they’re among the few birds that still have a penis. And what we find in ducks is, as a result of female resistance and male sexual violence, we find a co-evolutionary arms race between male capacity to force and female resistance.

In this case it takes place in the form of a genital arms race: the males evolve more elaborate and more elaborately armed penises, and the females evolve convoluted vaginal morphologies that exclude the penis during forced population.

So among the many weird things of duck penises is that they’re counter-clockwise coiled. Well, the female vagina (in ducks that have high rates of resistance) actually coils in the opposite direction, so they have literally evolved an “anti-screw” device in their vaginal tract that obstructs the intromission of the penis during forced copulation.

What that means is that what that tea party Senate candidate Todd Akin from Missouri said about women “have a way of shutting that whole thing down” in reference to rape is actually true of ducks. 

But in a way that exposes something fundamentally new and interesting about evolutionary biology, which is that sexual autonomy matters to animals.

Freedom of choice is not merely a political concept discovered by suffragettes and feminists in the 19th and 20th centuries, but is actually an evolved feature of the social and sexual lives of other species, especially in ducks.

How does this work? Well if the female mates with the male she prefers, that is she gets the green head and the “quack, quack, quack,” that she likes, and then her male offspring will share those traits and be sexually preferred by other female ducks who have coevolved those same aesthetic preferences.

But if she’s forcibly fertilized, then her male offspring will either inherit a random trait or one that she specifically rejected, which means that her offspring will be less attractive to other females.

So anything the female duck can do to prevent forced fertilization, through physical resistance or behavior, will evolve because she will be rewarded with more grandkids.

So what this means is that aesthetic norms, the shared ideas about what is beautiful among ducks, gives female ducks the evolutionary leverage to advance their freedom of choice in the environment of persistent sexual coercion and sexual violence. This is really stunning.

In fact we know these ducks are so successful, because in species where 40 or 50 percent of the copulations are forced only two to five percent of the eggs in the nest are fathered by males who are not the social partner.

What that means is that females have a 98 percent successful birth control device that is behaviorably deployable in the vaginal tract in response to sexual violence. That’s like FDA approvable.

And what that shows is the power of female choice to advance the sexual autonomy of individual females.

One of the interesting things we learned from examining sexual conflict in ducks is that the genital arms race between males and females is not really a fair fight. In fact the advances in male coercive capacity are really about control over female outcomes. They are about controlling—physically controlling—fertilization.

However, the countermeasures that females evolve are not actually about power or control, they merely reestablish the freedom of choice, if you will the flat playing field in which individuals are free to choose who they like.

Now this sexual autonomy is not actually about control or control over other individual’s sexual outcomes. That’s fascinating because this asymmetry between male coercion and female resistance in duck sex has really fascinating parallels to a patriarchy and feminism in cultures today.

So for example, patriarchy is historically—and even in a modern sense—about coercive control over female reproductive autonomy, whereas feminism is really an ideology of freedom of choice.

So that same symmetry between male power and freedom of choice is elaborate and present today.  And we can see this explicitly because patriarchy and men’s rights and “incel” movements all articulate feminism as a countervailing force of control over male reproductive outcomes, but that’s a fantasy. In fact sexual autonomy includes the freedom to be rejected, which is a lesson that we learn from duck sex.

Duck mating—for what it's worth—is a surprisingly complex issue with one hand (webbed foot?) in the #MeToo movement. Really. Richard O. Prum, Head Curator of Vertebrate Zoology at the Peabody Museum of Natural History at Yale University, has a lot to say about the matter. Did you know that male ducks often force sex on female ducks that aren't their mates, to the point where female ducks' genitalia has evolved to try and counteract what biologists have politely termed "forced copulation"? The lady ducks have found a way to shut out sexual predators. In other words: the power of the female's choice has literally advanced the species. Ultimately, Prum says, patriarchy is about "coercive control over female reproductive autonomy, whereas feminism is really an ideology of freedom of choice." Richard's latest book is The Evolution of Beauty: How Darwin's Forgotten Theory of Mate Choice Shapes the Animal World - and Us.

The “new normal” paradox: What COVID-19 has revealed about higher education

Higher education faces challenges that are unlike any other industry. What path will ASU, and universities like ASU, take in a post-COVID world?

Photo: Luis Robayo/AFP via Getty Images
Sponsored by Charles Koch Foundation
  • Everywhere you turn, the idea that coronavirus has brought on a "new normal" is present and true. But for higher education, COVID-19 exposes a long list of pernicious old problems more than it presents new problems.
  • It was widely known, yet ignored, that digital instruction must be embraced. When combined with traditional, in-person teaching, it can enhance student learning outcomes at scale.
  • COVID-19 has forced institutions to understand that far too many higher education outcomes are determined by a student's family income, and in the context of COVID-19 this means that lower-income students, first-generation students and students of color will be disproportionately afflicted.
Keep reading Show less

Why is everyone so selfish? Science explains

The coronavirus pandemic has brought out the perception of selfishness among many.

Credit: Adobe Stock, Olivier Le Moal.
Personal Growth
  • Selfish behavior has been analyzed by philosophers and psychologists for centuries.
  • New research shows people may be wired for altruistic behavior and get more benefits from it.
  • Crisis times tend to increase self-centered acts.
Keep reading Show less

How Hemingway felt about fatherhood

Parenting could be a distraction from what mattered most to him: his writing.

Ernest Hemingway Holding His Son 1927 (Wikimedia Commons)
Culture & Religion

Ernest Hemingway was affectionately called “Papa," but what kind of dad was he?

Keep reading Show less

How DNA revealed the woolly mammoth's fate – and what it teaches us today

Scientists uncovered the secrets of what drove some of the world's last remaining woolly mammoths to extinction.

Ethan Miller/Getty Images
Surprising Science

Every summer, children on the Alaskan island of St Paul cool down in Lake Hill, a crater lake in an extinct volcano – unaware of the mysteries that lie beneath.

Keep reading Show less

The biology of aliens: How much do we know?

Hollywood has created an idea of aliens that doesn't match the science.

  • Ask someone what they think aliens look like and you'll probably get a description heavily informed by films and pop culture. The existence of life beyond our planet has yet to be confirmed, but there are clues as to the biology of extraterrestrials in science.
  • "Don't give them claws," says biologist E.O. Wilson. "Claws are for carnivores and you've got to be an omnivore to be an E.T. There just isn't enough energy available in the next trophic level down to maintain big populations and stable populations that can evolve civilization."
  • In this compilation, Wilson, theoretical physicist Michio Kaku, Bill Nye, and evolutionary biologist Jonathan B. Losos explain why aliens don't look like us and why Hollywood depictions are mostly inaccurate.
Keep reading Show less