Half female, half male: the strangest mutation in birds and other animals (10 photos)

Yes, the preview photo shows a genuine androgynous bird, with one half of its body developing along the male line and the other along the female line. And the strangest thing is, it's not unique. Androgynous individuals have been found among 40 bird species, and they're so common that scientists have a special term for the phenomenon: gynandromorphism.





Let's start with the bird; we'll discuss arthropods below.



Male on the left, female on the right.

For such a strange creature to even come into being, everything must go wrong even before fertilization. First, an egg must be created with two nuclei instead of one. Then, it must be successfully fertilized by a sperm, after which the egg has a slim chance of developing into an adult animal, seemingly stitched together from two halves. Only one in thousands of gynandromorphs is ever born.





Chicken, are you okay?



Another gynandromorph discovered is the green sai from Colombia.

However, despite their obvious external oddities, gynandromorph birds appear to be remarkably normal. They forage for food, communicate with neighbors, chirp cheerfully, and search for a mate. Although these birds don't produce offspring, they live completely normal lives as either male or female—it all depends on which half's hormones take over.



The red cardinal has turned a little white.



A normal pair: female (left) and male (right) for comparison.

But hermaphrodite, half-breed birds are just the tip of the iceberg. The real treat is hermaphrodite, half-breed insects, spiders, crustaceans, and lizards, which look just as abnormal. And they all live, hunt, interact with their neighbors, and some even reproduce successfully, producing normal, healthy offspring. To date, scientists have discovered gynandromorphs among 150 animal species, and the list continues to grow every year. But there are practically no mammals on it.



In stag beetles, the size of their mandibles and the shape of their head depend on their sex. How the baby suffers.



Yeah, you can't really fly with that kind of asymmetry...



Even crustaceans can get mutations.

After all, in a sense, mammals are special. Our bodies are designed in such a way that the sex of an animal depends not so much on genes as on the hormones the fetus produces in the first weeks of development. Therefore, a "hormonal battle" occurs within the mammal between the two halves of the animal's body. And if it doesn't lead to its death, then one side inevitably wins, and the animal transforms into a normal male or female. It's possible to discover something is wrong with the organism purely by chance, through DNA analysis. Are there gynandromorphs among humans? Theoretically, yes, but in practice, not a single one has been found.



Despite the lack of gynandromorphism in humans, they can also be bicolor. At very early stages of development, two embryos can merge into one organism, transforming into extremely unusual individuals. Taylor Mule, an American singer, is one such person. Let us know in the comments if you'd like to read more about this.

However, nature itself Gynandromorphism still poses uncomfortable questions for scientists. For a long time, it was believed that the behavior of such animals was entirely determined by the dominant hormonal background—that is, a bird behaves either like a male or a female, period. But recent observations have shown that some hermaphroditic finches exhibit a completely unique behavioral repertoire, characteristic of neither sex separately. This means that the brains of such animals may operate according to their own logic—and we are only just beginning to understand it.