If you have ever seen mallards in spring you know that male mallards (drakes) are actually not as sweet and cuddly as they look. Given the chance they rather rape females, especially when a group of drakes is together.
It was long thought that females (hens) were the helpless victims in this and, given the fact that sometimes they drown during such an endeavor, you can’t blame anyone for that opinion.
The sex of most other birds isn’t all to exciting. The males lack external genitalia and females have a simple, as in straightforward and short, vagina. But not so the mallard and a number of other waterfowl.
It is all due to the battle of the sexes.
And that battle isn’t as unequal as it seems.
Enter the penis. Or actually the pseudo penis because it isn’t made from the same tissue as ours. The length of the pseudo penis of waterfowl is correlated to the frequency of forced copulations. Mallards don’t have the longest penises out there, but it has a considerable length. And it is counterclockwise screwed.