The twisted sex lives of ducks

If you think ducks are cute innocent birds, think again.

Duck sex is perhaps one of the most horrific events of the animal kingdom, involving penises with spines, explosive erections, and so much more.

Here are 5 fast facts of the twisted sex lives of ducks.

Fact 1: Duck penises can be very long

Duck penises come in all shapes and sizes. Image: Glen Bowman via Flickr.

A duck penis can measure anywhere between 1.25 centimetres, to over 40 centimetres long.

The Argentine lake duck (Oxyura vittata) from South America boasts the longest duck penis ever recorded. Measuring at 42.5 centimetres in length, its penis is just as long as its body.

So, where do ducks keep their junk if they’re that long?

Duck penises grow at the beginning of the reproductive season, and shrinks back down towards the end of the season. Males tuck their penis away inside a phallic sac until it’s time for action.

Fact 2: Ducks have explosive erections

After a male duck mounts the female, the erect duck penis explodes into the female reproductive tract, spiralling out like a missile. This all occurs in less than half a second, during which the penis can reach velocities of up to 1.6 m/s.

See for yourselves:

Fact 3: Some duck penises have spines on them

Along with cats, ducks are part of the barbed penis club. Many duck penises are elaborated with various spines, barbs, grooves, and other ornaments.

It is thought that having backward-pointing spines on their penises, allow some ducks to deposit their sperm further into a female to compete with rival males.

Fact 4: Rape is common amongst ducks

In many bird species, females tend to choose a mate after the male puts on an elaborate courtship display, and breeding pairs are often monogamous.

Ducks, however, are an exception. Ducks do pair off to mate, however stray males often force themselves onto females. This is especially true in Mallards (wild ducks).

“Rape is a normal reproductive strategy in mallards,” says Dutch researcher Kees Moeliker.

Although approximately 40% of duck sex is forced, only 1 in 4 matings are successful. Turns out, female ducks have some tricks under their wings to foil males’ attempts at forced copulation.

Fact 5: Female ducks have incredibly complex genitalia

The genitalia of female ducks can be just as ornate as male genitalia. They have evolved “maze-like” genitals with many twists and full of dead ends to stop the penis from everting.

There is such a poor fit between male and female genitals, that female ducks have to be mostly relaxed and willing for mating to succeed. Female ducks contract and relax internal muscles for males to achieve full penetration, increasing the likelihood of fertilisation.

There we have it. Ducks have no doubt, very twisted sex lives.

Cute no more. Image: Katdaned via Flickr.

For further leisurely reading about the sex lives of other animals, please see here:


2 Responses to “The twisted sex lives of ducks”

  1. jwhinfield says:

    We recently had a lecture on this, and it undeniably tarnished the reputation of ducks in my mind. Also covered in the lecture was “Penis Amputation in Hermaphroditic Banana Slugs” – might I suggest you explore this in a future blog post?!

    Given that the males often hang around to raise the chicks, does the situation sometimes arise that those duclings ain’t daddies? So, if the ducklings are the outcome of rape, is there a still a male involved in the rearing process? And what’s his relationship to the little ones?

    Great work Daph – dirty, grotty and fascinating 🙂

  2. Olivia Campbell says:

    In my year 7 science classroom at school there was a life size print out of a Argentine lake duck and its stretched out penis on the wall. It was one of the most shocking things I had ever seen as a year 7 girl! Reading this duck sex seems to be just as shocking to me now at 23 as it was at 13.