There comes a time in every science writer’s career when one must write about glass duck vaginas and explosive duck penises.
That time is now.
To err on the side of caution, I am stuffing the rest of this post below the fold. My tale is rich with deep scientific significance, resplendent with surprising insights into how evolution works, far beyond the banalities of “survival of the fittest,” off in a realm of life where sexual selection and sexual conflict work like a pair sculptors drunk on absinthe, transforming biology into forms unimaginable. But this story is also accompanied with video. High-definition, slow-motion duck sex video. And I would imagine that the sight of spiral-shaped penises inflating in less than a third of second might be considered in some quarters to be not exactly safe for work. It’s certainly not appropriate for ducklings.
So, if you’re ready, join me below the fold.
This story is actually a sequel. Back in 2007, I wrote in the New York Times about the work of Patricia Brennan, a post-doctoral researcher at Yale, and her colleagues on the weirdness of duck genitals. The full story is here. (Brennan also appeared in a Nature documentary, starting at about minute 38:35.)
In brief, Brennan wanted to understand why some ducks have such extravagant penises. Why are they cork-screw shaped? Why do they get so ridiculously long–some cases as long as the duck’s entire body? As Brennan dissected duck penises, she began to wonder what the female sexual anatomy looked like. If you have a car like this, she said, what kind of garage do you park it in?
Brennan discovered that female ducks have equally weird reproductive tracts (called oviducts). In many species, they are ornamented with lots of outpockets. And like duck penises, duck oviducts are corkscrew-shaped. But while male duck penises twist clockwise, the female oviduct twists counterclockwise.
Brennan speculated that all this bizarre anatomy is the result of a peculiar form of evolution known as sexual conflict. A strategy that allows females to reproduce the most offspring may not be so good for males, and vice versa. For example, male fruit flies inject their mates with lots of chemicals during sex, and those chemicals make her less receptive to other males, thereby boosting his chances of fathering her eggs. But those chemicals are harsh and will make female flies sick. Females, in turn, have evolved defenses against those chemicals, blunting their effects.
With many examples of sexual conflict in nature, Brennan wondered if sexual conflict between male and female ducks was giving rise to their weird genitals. Female ducks pair off with male partners for the breeding season, but they also get harrassed by other males, sometimes being forced to have sex (and sometimes dying from the attacks). A third of all duck matings are forced.
And yet only 3 percent of the ducklings that female ducks produce come from such forced matings. Brennan speculated that the female ducks can block forced copulations with their mismatched spirals. And they might also be controlling which drake got to fertilize their eggs by socking away the sperm of different mates in different pockets. And the extravagant penises of males might be the result of an evolution around those defenses.
As I reported in 2007, Brennan discovered a pattern that supported this hypothesis. Among 16 species of water fowl, species in which the males grew long phalluses also had females with more turns in their oviduct and more side pockets. The ducks were escalating an arms race, genital for genital.
But Brennan didn’t actually know how duck penises actually moved through the labirynthine oviduct, and how the oviduct’s shape might affect the drake’s delivery of sperm. So she traded calipers and rulers for high-speed video.
Brennan and her colleagues traveled to a California duck farm, where workers are expert at collecting sperm from drakes. The first step in the collection is to get a drake excited by putting a female duck in his cage. The drake climbs on top, and then the penis emerges. Before its emergence, a drake’s penis is usually completely hidden from view, tucked inside his body like an inside-out sock. Drakes unfurl their pensises differently than male mammals. In mammals, the penis becomes erect as blood flows into the spongy tissue. Ducks pump lymph fluid instead. And as the fluid enters the penis, it does not simply become engorged. It flips rightside-out.
Here’s how it happens, in slow motion. A Muscovy drake everts his penis in about a third of a second, at speeds of 1.6 meters per second.
Of course, drakes don’t mate with the air. Having made this video, Brennan still needed a way to see how a duck penis actually performs its appointed task. Unable to film duck penises in a real female oviduct, she built a fake oviduct out of silcone. She then managed to get a drake to mate with it. But the overwhelming force of the explosive penis broke the fake oviduct.
So Brennan turned to glass. Her new fake oviducts were strong enough to handle the drakes, and she started filming. Here’s what she saw.
As Brennan had predicted, the counterclockwise turns of an oviduct slow down the expansion of the duck penis, compared to a straight tube or a clockwise one. Brennan suspects that female ducks slow down males trying to force a mating, but they can also let their partner’s penis move faster through the oviduct. They have been observed to relax and contract their muscles arond the oviduct.
Female ducks can’t stop an unwanted male from delivering his sperm, but the obstacles in their oviducts may give them control over what happens to that sperm. The female ducks may use their oviducts to slow down the expanation of the penis, so that by the time the drake ejaculates, the sperm are delivered in the lower reaches of the oviduct. A female ducks’s partner, with her cooperation, can deliver sperm further up the oviduct. With the wanted and unwanted sperm delivered to different places in the oviduct, a female duck may be able to store the sperm in different pockets. And then she can choose which drake will father her duckling. For all the explosiveness male ducks may display, it’s the female ducks that get the final say.
[Postscript: I tell Brennan's story in more detail in my new book, The Tangled Bank: An Introduction to Evolution. It opens the chapter on sex--where I show how the same processes that explain these strange genitalia explain many other things in the natural world.]
Reference: Patricia L. R. Brennan et al, “Explosive eversion and functional morphology of the duck penis supports sexual conflict in waterfowl genitalia,” Proceedings of the Royal Society of London, doi: 10.1098/rspb.2009.2139
[Update: 12/23--a couple misspellings fixed]
December 22nd, 2009 at 10:11 pm
Jeebus, whatever happened to the gentle cloacal kiss?
December 22nd, 2009 at 10:31 pm
Apparently there’s a lot more involved in duck sex than making a poultry effort.
December 23rd, 2009 at 8:09 am
[...] read about this result at Carl Zimmer’s Loom, and at Ed Yong’s Not Exactly Rocket Science. BE SURE to watch the videos (not for the [...]
December 23rd, 2009 at 8:38 am
When will the prolific duck rape make it on to Law and Order: SVU? It’s time to break the silence.
December 23rd, 2009 at 9:19 am
The comments so far have been terribly unfunny.
[CZ: Well, HG, I think you'll have to step up to the plate and post a joke of your own. Them's fighting words.]
December 23rd, 2009 at 9:41 am
[...] Carl Zimmer on glass duck vaginas and explosive duck penises [...]
December 23rd, 2009 at 10:03 am
I think HG is just egging us on.
We just bought a male duck for Christmas. I now think I’ll let GrrlScientist do the
dissectiondressing. We might have to ask a female duck about stuffing, as they seem to be the experts.December 23rd, 2009 at 10:07 am
Wow, those are amazing ovi-ducks.
December 23rd, 2009 at 10:39 am
My goodness, why aren’t those scientists wearing sanitary gloves? Ewwwwww.
December 23rd, 2009 at 10:53 am
[...] duck sex. And not just the evolutionary scoop. He’s got slow motion video, too. All set up by this killer lede: There comes a time in every science writer’s career when one must write about glass duck vaginas [...]
December 23rd, 2009 at 11:09 am
[...] Brennan more justice than Carl Zimmer does, so I recommend that you head over to his post on The Loom. He includes video of a duck boner, as well as a duck penetrating glass tubes of different [...]
December 23rd, 2009 at 8:54 pm
Well, as long as we’re on the subject of kinky duck sex, I seem to recall that there was an ignobel award given out a few years ago on the subject of necrophilia between male ducks.
So, since I went there, it also seems like a good time to mention this recent story Bug powder causes male bedbugs to stab each other to death with their penises.
December 23rd, 2009 at 9:13 pm
Don’t get your feathers ruffled, HG!
December 24th, 2009 at 1:55 am
that’s fowl
December 24th, 2009 at 1:56 am
absolutely fowl
December 24th, 2009 at 12:31 pm
There’s a bunch of ducks near my work, so every spring I get to watch several duck gang rapes. One time I did see the duck’s penis and OMG.
I’m glad to hear the lady ducks have at least some defense against this crazy behavior…
December 24th, 2009 at 6:20 pm
If nothing else, the use of those glass models prove that males will mate with basically anything.
December 24th, 2009 at 6:43 pm
[...] going to want to check out Carl Zimmer’s full article about what exactly is going on here. Essentially, evolution has caused duck penises and duck [...]
December 24th, 2009 at 7:40 pm
[...] going to want to check out Carl Zimmer’s full article about what exactly is going on here. Essentially, evolution has caused duck penises and duck [...]
December 24th, 2009 at 11:00 pm
[...] going to want to check out Carl Zimmer’s full article about what exactly is going on here. Essentially, evolution has caused duck penises and duck [...]
December 25th, 2009 at 1:32 am
I have now seen things that can never be unseen. I did not know that there were clips of male duck genitalia out there, and I did not know how little I wanted to see it. Interesting!
Merry christmas, folks and ducks.
December 25th, 2009 at 9:14 am
[...] 来自耶鲁的研究者（论文猛击）通过各种实验，如长度测量，试管引导等，为大家呈现了一个生动活泼而又拍案惊奇的鸭子。嗯，鸭子赢了。在短短的不到1/3秒的时间内，公鸭以1.6m/s的速度完成JJ旋转和勃起。视频： vimeo源。 [...]
December 25th, 2009 at 10:22 pm
[...] Kinkiness Beyond Kinky, in The Loom. [...]
December 25th, 2009 at 11:44 pm
‘So Brennan turned to glass. Her new fake oviducts were strong enough to handle the drakes, and she started filming. ‘
A different meaning in a different context, eh?
December 26th, 2009 at 1:36 am
So why isn’t the same thing happening with humans, or is it?
December 26th, 2009 at 4:02 am
No wonder Donald was so uptight. He was with the wrong lady all that time. I’d be angry too.
December 26th, 2009 at 4:43 am
I just hope the person in these videos is a bona fide scientist, not a mere duck fluffer.
December 26th, 2009 at 5:46 am
So what does your daddy do?
Oh he films drakes having erections!?!?
December 26th, 2009 at 7:54 am
#24 i think you might be on to something.
December 26th, 2009 at 7:58 am
Wow. People who think furries are freaky ought to check out real life.
December 26th, 2009 at 8:35 am
I hope you bought that duck dinner first.
December 26th, 2009 at 10:32 am
Total Duck pr0n! Do we know if these ducks were of age and this site was in compliance? On a serious note- this is fascinating. Was it Brennan who debunked the cyber myth about dolphins having prehensile penises? Good work Patricia. I look forward to further research.
December 26th, 2009 at 11:21 am
If you were any kind of a science writer you would use the proper latin plural of penis: penes. “Penises” might be as acceptable a variation the same as “ain’t” is for “isn’t,” but it is not correct. So, the next time any of you boys and girls see more than one penis, please, say PENES.
CZ: Penises is perfectly acceptable. You can look it up in a dictionary. Or you can read the paper about which I’m writing. Let me quote: “The erect penises of mammals and turtles are stiff hydrostats supported by axial-orthogonal layers of inextensible collagen fibres.”
Forgive me if I don’t retire early.
December 26th, 2009 at 11:31 am
If he’s clockwise and she’s counterclockwise, it seems like while he’s screwing, she would be unscrewing and they would never get anywhere.
December 26th, 2009 at 11:41 am
[...] brief, Brennan wanted to understand why some ducks have such extravagant penises.” The article only gets better from there. Includes tales of exploding artificial duck [...]
December 26th, 2009 at 11:56 am
But why are drake penises curved at all? If they were straight, those males forcing sex would be at less of a disadvantage regardless of whether female genitalia curved clockwise or counterclockwise. [Does this imply that the two flip directions periodically?]
December 26th, 2009 at 12:29 pm
While TC was kind of an asshole about it, he does seem to be right about this rather pedantic issue.
Here’s a quote from the dictionary.com page that you linked. “The proper plural is penes.” You have to scroll down to the heading “Word Origin and History.”
It seems that “penises” is the dominant form in current usage, but this is a change from the latin origins and historical English spelling. The issue is that the word has passed out of the hands of the medical and scientific communities, and the general public has abandoned the Latin pluralization for the dominant English form. This development is relatively recent in historical linguistic terms.
I’m sure that your editors know what’s best for their readership. It’s all just a piece in the ever-changing tapestry of modern language.
Great article, btw.
[CZ: Thanks, David, on the post. TC wasn't talking about a historical shift, but actually claiming that penises was the equivalent of ain't. But ain't is considered non-standard, while penises is perfectly acceptable according to several dictionaries and is used by scientists themselves in scholarly publications.]
December 26th, 2009 at 1:01 pm
[...] science writer’s career when one must write about glass duck vaginas and explosive duck penises. Kinkiness Beyond Kinky | The Loom | Discover Magazine « Don’t they care that the product they’re defending is basically [...]
December 26th, 2009 at 2:26 pm
[...] Sorry 2009 December 26 by manshine http://blogs.discovermagazine.com/loom/2009/12/22/kinkiness-beyond-kinky/ [...]
December 26th, 2009 at 4:35 pm
I hope that now people will stop suggesting rape is “natural” giving the duck example from “nature”, without considering the complexities of evolution and how it works within and across species.. Until humans develop twisty, penis biting vaginas, put rapists in jail please, where they belong. Thanks!
December 26th, 2009 at 4:42 pm
So, now we know why Walt always drew pants on Donald!
December 26th, 2009 at 8:52 pm
On the topic of ‘Penes’ versus “Penises”…
The use of language is to communicate. Another example that comes to mind is that of ‘Octopus’. People often try to say ‘Octopi’ for the plural of Octopus, when the word originally came from Greek, not Latin. IIRC, the technically correct plural of it is ‘Octopetes’. If I actually used ‘Octopetes’ in a sentence, though, no one would have any idea what I really meant. In everyday English, we should just say ‘Octopuses’, because others will know what we’re talking about. While ‘Penes’ is technically correct, I find ‘Penises’ to be perfectly acceptable.
On the subject of animal rape: It may be ‘natural’, but that does not make it right or good. Murder occurs ‘naturally’ among many species, but we won’t stop putting people in jail for that!
December 27th, 2009 at 2:27 am
[...] “In brief, Brennan wanted to understand why some ducks have such extravagant penises. Why are … [...]
December 27th, 2009 at 4:30 am
[...] than you ever wanted to know about ducks Kinkiness Beyond Kinky | The Loom | Discover Magazine __________________ When a passenger of the foot moves in sight, tootle the horn trumpet [...]
December 27th, 2009 at 10:22 am
@Naked Bunny: I can see a whole new furry(or rather, feathery) sexual subculture emerging from this. (If it doesn’t exist already– not like I’d know.)
December 27th, 2009 at 12:40 pm
[...] One hesitates even to guess what an analogous organ on a human being would be — six feet long, maybe? In any event, as a longtime propounder of the wonders of the natural world here at ErosBlog, I was promptly hooked by Zimmer’s blog post. [...]
December 27th, 2009 at 1:32 pm
The pic of the strung up drake at the top of the article leads me to believe there will soon be a BDSM site for this, with some very creative and intricate CBT equipment devised.
Seriously though…ducks, and their observers, have been around for ages; so why is this not already common knowledge?
December 28th, 2009 at 8:51 am
[...] comes a time in every science writer’s career when one must write about glass duck vaginas and explosive duck [...]
December 28th, 2009 at 9:31 pm
You learn something new every day. I thought “ain’t” was a contracted form of “am not”, the plural of penis was either penises or penes, and that the plural of octopus was either octopuses, octopodes, or octopi. I guess I was wrong on all counts.
December 29th, 2009 at 9:03 am
[...] years. Why are drake penises corkscrew shaped? Why are they so long? Discovery’s Carl Zimmer reports: As Brennan dissected duck penises, she began to wonder what the female sexual anatomy looked like. [...]
December 30th, 2009 at 1:57 am
Judging by the amount of academic “giggling” here, we haven’t been able to abandon our speciesism roots. Imagine what ducks would write about here. Would they consider their anatomy at all unusual? Would they be saying “ew, gross!”? Fact is, all life is mechanical -no less our own- and there are no morals. It all solves the desires of DNA using the tools at hand (carbon, hydrogen, oxygen mainly). We consider duck penises erotic because we compare them to ourselves. We don’t feel that way about bacteria reproducing; they’re too different. Regarding ducks having erections into glass tubes: is that any different from ourselves? We can be stimulated by a two dimensional image printed on a scrap of paper. We’re all animals; we all work the same way. The brain does the bidding of our genes, not vice versa.
December 31st, 2009 at 6:48 pm
…damn, watching that gave me a cramp!
January 1st, 2010 at 5:13 am
[...] a post-doctoral researcher at Yale, and her colleagues have unlocked many of the mysteries behind ducks and their extremely weird genitalia, including (but not limited to) the males’ explosive erections. And there’s [...]
January 2nd, 2010 at 12:08 am
Sounds like quack science to me.
January 2nd, 2010 at 10:10 pm
You lead in with “To err on the side of caution, I am stuffing the rest of this post below the fold. ” Pity your webmaster didn’t agree, as that sentence appeared less than half-way down the height of a photo… which really could have used a fold. (In other words, “YIKES!“)
Also, that’s a heckuva lot of lymph! Is there a reservoir or something?
January 2nd, 2010 at 10:19 pm
Also Steve #51: “Imagine what ducks would write about here. ” They’d probably snicker at our inadequacy.
January 2nd, 2010 at 11:52 pm
… Why would anyone take this as a “rape is natural, therefore good” idea?
First, why wouldn’t it be explained by a culture? It’s actually really stupid to believe that other animals don’t have a culture merely because we can’t understand them and we’re too arrogant to learn the inflections of body language and scent.
Second, this is a defense against rape, or forced sex, or whatever. The female ducks are evolving a defense against their attacker’s offspring, and they can/do encourage their willing partners. So… wouldn’t that be an argument for consensual sex, and against rape as a method of procreation?
Does it make too much sense? I swear to god, I do not get people these days.
January 3rd, 2010 at 4:03 am
[...] titeln är inget skämt utan rör RIKTIG vetenskap! Läs rapporten i Discover och se videoklippen. Eller kan ni komma på en mer kinky början på det nya året [...]
January 4th, 2010 at 11:30 am
This is the first time I have ever learned something and felt stupid for learning it. Was money really wasted to find this out and people are dying, starving, and plenty of actual wrong going on and here these people are studying duck dicks come on people. figure out how to make the government start using water as fuel.
[Carl: As a civilization, I would hope we could chew gum and walk at the same time. That is, be able to support basic research on things like evolution while also figuring out new solutions for our energy demands.]
January 4th, 2010 at 12:10 pm
Duck Love…
Ducks are a special birds. Not many birds have penises, but ducks certainly do. It’s not just any penis, either. Ducks have explosively erecting, corkscrew-shaped penises. They look more or less like this, depending on the species of duck.
L…
January 4th, 2010 at 10:44 pm
[...] Bug powder causes male bedbugs to stab each other to death with their penises 2. glass duck vaginas and explosive duck penises 3. how to masturbate an elephant (and it’s a proper [...]
January 7th, 2010 at 1:08 pm
[...] want to read the article just watch the videos. I was impressed and disgusted at the same time… Kinkiness Beyond Kinky | The Loom | Discover Magazine __________________ Science is nothing but developed perception, interpreted intent, common sense [...]
January 18th, 2010 at 1:49 pm
[...] my wisdom, I decided that nothing summed up the situation today with science journalism better than duck sex. And, as I discovered, ScienceOnline is just the sort of place where the audience gets [...]
January 18th, 2010 at 5:16 pm
[...] a foot in MSM and the blogmos, talked about how, after the NYT’s passed on it, his posting videos of duck sex with artificial duck vaginas went viral. This reminded me of the fact that my all-time greatest hit on flickr is a picture [...]
January 23rd, 2010 at 12:10 am
[...] today. Selfish, because this article isn’t new, and was reported on by one of the GREATS. This guy. He (of course) did a completely brilliant job, and when he talked about it at SciOnline this past [...]
January 23rd, 2010 at 11:23 am
It will be interesting to see if this defense becomes their downfall. As Mallard ducks become the predominant species in most of Eastern Canada, this selective breeding defense is less desirable. Mallards now make up the majority of the duck biomass displacing many other species for food and nesting area.
Could it be that Mallards do not have such similar genitalia??
Forced mating frenzies are quite common with Mallards with several males taking their turn. It is often a wonder the females do not drown.
January 23rd, 2010 at 7:51 pm
This sheds a whole new light on the idea of “screwing”.
January 27th, 2010 at 10:25 am
[...] crazy, so exciting and so important to every day life. I mean c’mon, you can’t tell me exploding duck penises wouldn’t make great television… [...]
February 18th, 2010 at 11:43 am
Think,every one has a creator.who make this amazing creations?the answer is only one -THE GOD- then turn to the creator that is only way to victory.for details see the last vedha QUR-AN.
February 24th, 2010 at 4:41 pm
[...] A fascinating article about sexual-conflict evolution in ducks. Comments [0]Digg it!Facebook [...]
February 27th, 2010 at 4:28 am
[...] “Kinkiness Beyond Kinky,” Carl Zimmer, Discover [...]
March 7th, 2010 at 9:34 am
[...] C: Is that the duck thing? [...]
March 19th, 2010 at 9:52 pm
[...] by Yale’s Patricia Brennan (written up here by Ed Yong and here by Carl Zimmer) sets out to explain what you are no doubt wondering yourself: why corkscrew [...]
April 2nd, 2010 at 11:47 am
[...] boy, you simply have no idea! The things I could tell you! Well, like I said, I have been a bad duck…..a very bad [...]
April 4th, 2010 at 10:44 am
[...] shit against the wall in the hope that it helps them stick, as it were, from copulatory plugs to corkscrew vaginas. Yep, it’s that old trope about the war of the sexes, and often what’s good for the [...]
June 2nd, 2010 at 8:09 pm
[...] enough? Read about it here This entry was posted on Thursday, June 3rd, 2010 at 12:05 am and is filed under Celeb Scandal. [...]
July 26th, 2010 at 8:39 pm
[...] haven’t read any of his stuff on sex, you may want to begin by delving into the world of kinky duck sex. I owe Carl a special thank you for his Science Online 2010 discussion on duck genitalia, for it [...]
August 3rd, 2010 at 3:02 am
[...] Here are the basics: Corkscrewed vaginas and long, temporary, lymph-filled penises that uncoil in fractions of a second. Now researchers have found that some males’ members grow longer when they’re fiercely [...]
August 6th, 2010 at 1:35 am
@41 Ziggy… um, what? Mickey wore pants, Donald didn’t.