The male duck's penis is spiral-shaped: like a corkscrew, it twists in a counter-clockwise direction so that sperm will target the oviduct on the female's left-hand side. In almost all birds only the left ovary is functional, but in a 2007 study, Brennan and colleagues noticed that in ducks the female's vagina twists in the opposite direction.
Brennan thinks that, while the males are evolving long and flexible penises to help them force copulations, the females are using their complex vaginal anatomy to take back control over which sperm fertilises their eggs. When a female wants to mate with her chosen partner, she can make the process easier by relaxing the muscles around the vagina entrance.
Brennan's team also timed the male's penis eversion, which took a mere one-third of a second - around 60 times faster than was previously thought (see video above). "This definitely gives the males a mechanism by which they can copulate," says Brennan, who was taken aback by the speed. "To be totally honest, I'm still in shock," she says.
Today in Torture Phallus news:
Ducks fight the battle of the sexes in their genitals
Tags: doomed, mpegs, mutants, parts, perversions
Current Music: Oxygiene 23 -- Adonis ♬
You've seen this article? Better video links as well, depending on one's definition of "better". :)
Why don't you pick up
How Animals Have Sex: A Guide to the Reproductive Habits of Creatures Great and Small ? It even has an example of relative monogamy in animal kingdom. It's by the author of the Pirates! series, so be ready for some British humor.
On the original article there are more redacted comments than real comments.
There's something quintessentially Internet about an embedded video which displays the title "Duck erection" for a brief moment before changing to "Sponsor message".
I've actually seen ducks having sex, and it's pretty brutal. Basically, the male uses his head to force the female's head underwater for extended periods of time while he's mounting her. It's like watching a Rocco Siffredi movie.
This video includes a prostitute duck.
This does not seem to match up with the condom depicted in the film Howard the Duck....