Have you ever taken a close look at any male bird and wondered why they don’t have a penis? No? Well, me neither (I’m not that much of a pervert!)
But after writing my previous article on the Greater Vasa Parrot and their interesting sex lives, I learned that of the 10,000+ species of birds in the world, only 3% of them (which includes the Greater Vasa Parrot) have functional penises.
But, why?
It turns out bird embryos do have penis precursors, but a genetic signal causes the penis cells to die off during gestation.
Although this explains the how, it doesn’t explain the why. There are many theories, but so far, scientists just don’t know why.
It could just be a side effect of other bodily changes. The protein that causes penis cells to die off during gestation is also found in the transition from scales to feathers, the loss of teeth on their beaks, and variations in beak size
It could be that a penis-less bird finds it easier to fly (most bird penises are only found in waterfowl like ducks, geese and swans, and large flightless birds like ostriches and emus)
It could be that penises carry a risk of passing on sexually-transmitted infections
It could be that a lack of a penis means less mating time, which means they can better avoid predators
The Common Ostrich has a penis that measures around 26cm long (or 10 inches). Please scroll to the very bottom to see a NSFW picture.
Notable bird penises: Muscovy ducks
One of the most well-known stories of bird reproduction is of the Muscovy Duck’s evolution of a corkscrew penis to fit a corkscrew vagina.
Male ducks are known to violently force themselves onto females. Over the years, female ducks began evolving a uniquely shaped vagina as a sort of physical barrier that prevents a rogue male from launching his ballistic penis to its fullest extent within her body.
In turn, to gain the edge, male ducks then evolved large corkscrew phalluses, lined with ridges and backward-pointing spines, which allow them to deposit their sperm into a female’s corkscrew-shaped vagina anyway…
How do the other 97% of birds mate without a phallus?
Since most birds do not have a phallus, they have evolved to eject sperm out of their ‘cloaca’ when mating with females. The cloaca is an orifice also used to excrete urine and feces.
The males eject their sperm directly into the cloaca of a female, and this maneuver is known by the touchingly romantic name “cloacal kiss”.
You’ve reached the end of today’s newsletter! As promised, here is a NSFW photo of a Common Ostrich’s 26cm/10inch long phallus.
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