# Why did humans choose to domestic only the birds with penises? **URL:** \ **Category:** Factual Questions\ **Created:** [December 31, 2019, 9:37pm UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692 "2019-12-31T21:37:10Z")\ **Posts on this page:** 6\ **Page:** 2
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [January 1, 2020, 4:53pm UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692/21 "2020-01-01T16:53:33Z")
Pigeons aren’t just pets, they were also raised for food (and sacrifice). And wild ducks & geese have penises, not just the domesticated ones. Guineafowl also don’t have penises. Basically, that quote is a load of nonsense. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [January 1, 2020, 5:51pm UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692/22 "2020-01-01T17:51:24Z")
So, on the one hand we have the non-functional vestigial homologs. On the other hand, we have numerous cases of pseudo-penis, including the weavers mentioned by Colibri, but not limited to birds. > **[Pseudo-penis](https://en.wikipedia.org/wiki/Pseudo-penis)** > > A pseudo-penis is any structure found on an animal that, while superficially appearing to be a penis, is derived from a different developmental path. > In mammals, all intact developmentally typical males have a penis, but the clitoris in the females of the following species is sufficiently enlarged that it is usually termed a pseudo-penis: spotted hyena, juvenile fossa, binturong, lemur and spider monkey. The enlarged clitoris in the fossa is supported by an os clitoridis, a bone similar to the ... One of the most fascinating cases is the _female_ spotted hyena. Spotted hyenas have complex social structures in which females are dominant. Females are larger than males, with high testosterone levels. They have no external vaginal opening, and the clitoris is enlarged into a pseudo-penis as large as the male’s true penis, making the sexes hard to tell apart except by body size. Females with young cubs have distended mammary glands _and_ an apparent penis, so they were once thought to be hermaphrodites. The females use the pseudopenis to urinate; the male penis must be inserted through the female pseudopenis in copulation, an awkward process; and they _give birth_ through it. Incidentally, spotted hyenas are wonderful animals - highly intelligent, curious, with complex social structure. Their negative reputation in both Western and African culture is undeserved. Even the notion that they are sneaky scavengers are wrong, they hunt at least half of their own food; and they are hardly cowardly, they will defend their kills against lion. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [January 1, 2020, 10:14pm UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692/23 "2020-01-01T22:14:16Z")
> [@Horatio\_Hellpop](#): > > Why aren’t pet birds–parrot, canary, cockatoo, pigeon, falcon–included in your definition of “domesticated”? Can’t speak for pigeons, not having direct experience with them. Or canaries. However parrots (and cockatoos, which are also parrots) are not domesticated. They are wild animals that are imprinted/tamed with each generation. It will take more time before they can be truly said to be domesticated. And they do not have penises. Falcons are not domesticated, either. Falconry birds are caught from the wild and they aren’t pets. It’s more of a business relationship with a professional hunter. I have no idea if falcons and other raptors have penises, not having direct experience with them. I’m going to guess not just because most flying birds don’t have them. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [January 1, 2020, 11:15pm UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692/24 "2020-01-01T23:15:47Z")
There are plenty of penis lacking domestic birds, just check out a good pet store. What you are referring to is livestock birds. The theory is that flight comes with a cost, meaning to drop weight everywhere you can to have the biggest advantage. One thing that went in many birds was the penis, but if you are still lugging around a wanker, your evolutionary path didn’t really concentrate in weight dropping, thus more meat, and perhaps easier to catch - thus more desirable for a dinner bird. ---
**Author:** ![Morgyn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/morgyn/32/3041_2.png) [@Morgyn](https://boards.straightdope.com/u/Morgyn)\ **Post date:** [January 2, 2020, 12:02am UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692/25 "2020-01-02T00:02:52Z")
Yeah, I meant livestock. That was \*not \*a well-worded question. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [January 2, 2020, 12:27am UTC](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692/26 "2020-01-02T00:27:32Z")
There’s a paper here on the molecular genetic basis for the loss of penis in most birds, including background discussion of various evolutionary hypotheses. > **[Developmental Basis of Phallus Reduction during Bird Evolution](https://www.cell.com/current-biology/fulltext/S0960-9822(13)00503-4)** > > One of the most puzzling events in evolution is the reduction and loss of the phallus > in birds. All birds reproduce by internal fertilization, but only ∼3% of birds have > retained a phallus capable of intromission. A number of hypotheses have been... [Previous page](https://boards.straightdope.com/t/why-did-humans-choose-to-domestic-only-the-birds-with-penises/845692.md?page=1)