A gynandromorph cardinal: one half male, the other half female

Male cardinals are bright red while females are a dull brownish color to provide camoflauge. This particular bird sports the colorations of both birds and is literall split down the middle.

Here’s photographer’s description of how he saw the bird:

"As you can see, the left side is male and the right female. For two winters the bird appeared at the feeder of a retired high school biology teacher. I was able to observe it on several occasions, and noticed that it didn’t associate with other cardinals, nor did I hear it produce any vocalizations. We attempted to capture it with mist nets so that Rob Fleischer and I could get blood samples for further study, but we caught every bird in the neighborhood except this one! Alas, it never returned the third winter.

This, by the way, is a very graphic demonstration of the differences between males and females, with the brighter color of the male almost certainly reflecting sexual selection (with bright colors presumably advantageous in males because they attract females, but disadvantageous in females because they attract predators).

Now how does this happen? I used to see this sometimes in my Drosophila flies, and we’ve long known how a half-male, half-female fly forms. In flies the sex is determined by the ratio of X chromosome to autosomes. Flies, like all diploid species, have two copies of every autosome. If you also have two X chromosomes, you’re a female because the ratio of autosomes to Xs is 1:1. If you have one X chromosome and one Y chromosome, your ratio is 2:1 and you’re male. The Y doesn’t matter here: if you lose a Y chromosome, and hence are XO, you still look like a male, although you’re sterile (the Y carries genes for making sperm).

So to get gynandromorphs in flies, all that has to happen is that one X chromosome gets lost in one cell when the initial cell in a female (XX) zygotes divides in two. One half of the fly then becomes XX, the other XO, and the fly is split neatly down the middle, looking like the one below. But gynandromorphs don’t have to be “half and halfs”. X chromosomes can get lost at almost any stage at development, so flies can be a quarter male, have irregular patches of maleness, have just a few male cells, or even a male patch as small as a single bristle.

But in birds, unlike flies (or humans), the females are heterogametic: i.e., their sex chromosomes are different (the females are called ZW; and the males are ZZ). I’m not sure whether chromosome loss is involved in the production of this cardinal, or how that loss affects sex determination in birds (in humans, for example, unlike flies, the Y chromosome is important, so XO individuals are not phenotypic males but largely phenotypic females). An article at Live Science on a similar gynandromorph cardinal in Texas offers the following theory, based on the observation that in gynandromorph chickens the female side is the normal ZW and the male side the normal ZZ:

It’s not known exactly how gynandromorphy happens in birds, Arnold said. The predominant theory is that an error occurs in the formation of an egg, which normally carries one chromosome to unite with the single chromosome carried by the sperm. But if an egg accidentally ends up with two chromosomes — a Z and a W — and if this aberrant egg is fertilized by two Z-carrying sperm, the bird that results will have some ZZ cells and some ZW cells, he explained.

That seems unlikely to me because it requires the concatenation of two rare events: an egg carrying two sex chromosomes instead of one (but the normal half complement of autosomes), uniting not with one sperm but with two." (SOURCE)

Responses to "Half Male, Half Female Cardinal (Photos)"

  1. Anonymous says:

    That's cool

  2. Anonymous says:

    Humm, if this is real I find it quite interesting.

  3. Anonymous says:

    Quite Beautiful! When I was young,in Michigan, my mother fed all the reject birds that didn't have a flock and couldn't migrate and one was a male cardinal with a big white spot on his side. He stayed all winter and through the spring, summer, and fall. So did the one legged birds, miscolored birs and etc. Thanks for publishing this. It was quite interesting!!

  4. Anonymous says:

    Wow, neat, ashame he,she didn,t come back!

  5. Anonymous says:

    a genetic mistake occurred during the first cell division of the fertilized ovum, causing one of the cells produced by this division to be male and the other to be female. As this egg developed, the entire right side remained female and the left side remained male,” Ammann continued.

  6. Anonymous says:

    Im not buying the male/female combination. What i am thinking is the combanation of a partial albino and partial color~ and weather the bird is male or female you'd need to test the actual bird i would think to know for certain, unless some marking shows w/ out question. I would submit this to 'BIRDS and BLOOM' magizine~ and see what they say if it was in my hands.

  7. Anonymous says:

    Have you ever taken a science class, Anonymous person above? Of course this is real! It even happens in humans who are born with both male and female parts. Look up gynandromorph.

  8. It looks like a mosaic of albino and normally pigmented male. It must be a somatic mutation. It is unusual for a mosaic to be so evenly divided along the middle, but it is possible. It seems a better explanation than a half male, half female bird.

  9. Amazing, either way.

  10. Anonymous says:

    photo shop...I might have believed it more if the paint job wasn't soooo's amazing what people will believe...LOL! Cute pic, but not real!

  11. Anonymous says:

    so interesting.......

  12. Anonymous says:

    Genetic malformations are not uncommon as they happen in all species. In humans the deformaties are expressed as polio,deformed limbs, and many other genetic malformations or genetic malfunctions. It is very possible that the great majority of these in humans and other animals, may be in great part due to the pollution of our earth due to and contributed by man's violation of nature. Let's look at what is done to the majority of our foods and the environment; and we'll find the causes for these peculiarities.

  13. Anonymous says:

    come on stop with the error and malformation, this is an awesome bird and perfect just the way it is

  14. Susi Green says:

    God's paintbrush at work again. To quibble over whether it's real or not is not unlike quibbling over whether there's a God or not -- or which one is real, for that matter. In a world full of smoke and mirrors, this is just a reminder that everything is possible.

  15. Anonymous says:

    In some animals, including humans, you can have two normal diploid fertilized eggs fuse at the single-celled zygote stage and then proceed to divide in such a way that half the resulting individual is derived from one and half from the other. It's called chimerism. Maybe eight or ten years ago JAMA or NEJM published a picture of a chimeric baby who was half male and half female. He/she/herm had been derived from zygotes fathered by two different men or one guy with a good range of skin color alleles, because one half of the baby was quite pale and the other clearly African-American, with a crisp vertical line down the middle exactly like this cardinal. (So no, it's not Photoshop.) I remember thinking that if the poor kid was otherwise healthy and grew up that way, he/she was going to get endless abuse every single school day for twelve years.

    You can also have microchimerism whereby most of the individual is derived from one zygote but just certain tissues from a zygote absorbed a little later in the process. There are actually men who have different genotypes and blood groups in their blood than in their sperm. It's been noted that a rapist with this anomaly could be wrongly exonerated by a DNA test that uses blood. It's probably a very rare anomaly ... but who knows?

  16. Anonymous says:

    Amazing what people will believe...

  17. Anonymous says:

    my name is martin this is a fantastic brid and a great photo one would think if they did not try to capture it maybe it would have come back.. It knew all the other brids where being cought...or maybe it passed, however it is again, FANTASTIC to see....peace

  18. Unknown says:

    Love it

  19. Anonymous says:

    Years back I had a balk Cardinal, that used to come to my bird feeder in Indiana. It came when sparrows were feeding, not ever with any other Cardinals.

  20. Anonymous says:

    Sorry, I meant bald cardinal. Should have proofed my comment.

  21. Anonymous says:

    You sure he just didn't fall in some red dye,lol

  22. Anonymous says:


  23. Unknown says:

    I think ALL chimeras are beautiful and it has to do with twin genes..... I think the cardinal may be very well a chimera....not male female....but I am not a scientist with degree but have many years of study and even in the area of genetics and abberations.... These animals are ALWAYS STUNNING to look at but I was wondering if they tested it's genes?

  24. Unknown says:

  25. Anonymous says:

    Scientifically I agree with a gyandro whatever it is. Ive taken sci class. But the pic is photoshopped to catch your eye. Nowhere in history have I seen half color anything. Humans who are gyandromorphs either favor more female or more male but never half and half. Yes, their genitalia are shot out to hell but otherwise we wouldnt know the difference if we didnt go "down town". So yes the bird may be both sexes, but the split colorings are a bit far fetched..... lots like a Jackaloupe...

  26. Unknown says:

    I live in Australia and I once saw this exact thing in a Magpie Lark. They look quite similar but bear different facial markings and this bird was male down one side and female on the other. I only ever saw it once and I know my local birdlife pretty well.

  27. Anonymous says:

    I have never seen this phenomenon but however it happens, it's amazing, quite interesting and definitely beautiful!

  28. Anonymous says:

    very rare I never seen one.amazing..

  29. Anonymous says:

    This is really cool!

  30. Anonymous says:


  31. Anonymous says:

    For all of you quick and obviously ignorant naysayers, read a book, ask some questions about this world... Don't just dismiss natural science and unique phenomena due to your own lack of knowledge. Get out of the house now and again... The world is crazy beautiful...

  32. Unknown says:

    This Is The First Time I Ever Saw Something Like This & It Is Very Interesting!

  33. Yeskeya says:

    NIce article. Too bad you didn't catch it for testing. I can't believe people are calling fake and photoshop. You're on the internet, use it for more than bashing someone. Look things up, do research, learn something about the world outside your window. Natures' creatures are amazing. I've seen chimera cats, piebald deer, and an albino red fox. There's so much to see if you only take the time. Thank you for the article and keep looking for the amazing in our world!

  34. Pan says:


  35. Anonymous says:

    Nature is a jokester some times. I think the bird is (was) lovely. Humans are sometimes born with dual sexuality also (and doctors are finally learning that it is best to leave them that way).

  36. Anonymous says:

  37. Sandra H. says:

    explains how it happens.

  38. Unknown says:

    However it happens, it is AMAZINGLY BEAUTIFUL ! I have a question for you .....Does that mean whenever the colors aren't "normal", is why? I wonder how much of it has been caused by what many of us two-leggeds have done and are still doing to our atmosphere, Mother Earth and all the waters upon her.

  39. renee wessman says:

    I have had one in my yard for 2 yrs. (I worry every winter abt the hawks)....she has large white splotches all through her body. I was told it was caused by a lack of melanin. when she flys she is amazing to see. don't have strong enuff digital to get a good pic.....

  40. That's a beautiful story. Thanks for your memories.

  41. That's a beautiful story. Thanks for your memories.

  42. Unknown says:

    Thank you for sharing such a wonderful story. I really enjoyed it.

  43. Anonymous says:

    Great story, enjoyed, sorry the bird never came back

  44. Anonymous says:

    A reputable enough source I'm hoping

  45. Anonymous says:

    I agree, I was just enjoying the bird.
    I am 100% recovered, however my brother and I cought polio as small children in '56 during a world wide epidemic by playing in a shalow excuses but I have a dificult time with ignorance.


    Loved the article; very interesting and unlike some with closed minds who take no joy in the wonders God provides...whether by divine design or genetic mutation as a result of nature or environmental toxins, I don't believe anyone is good enough at photo shopping to make me believe this is cardinal is not legit. It is a rare phenomenon, but it does happen. I am someone born with a rare disease due to a genetic mutation. Many animals (news flash, skeptics...humans ARE animals!) are born with differences due to genetics, whether presented as various illnesses, physical abnormalities, obvious physical coloring oddities, behaviors and INVISIBLE abnormalities that show no outward symptoms i.e. blood, bone, brain, muscle. Like others have said, naysayers get off your lazy asses, stop gaming for an hour, and do a bit of research before you mouth off as the ignorant expert you ARE NOT. Do yourself and the rest of us a favor, tyvm. Peace.

  47. Miss Kris says:

    To all the nay-sayers: This is a real phenomenon.

    These gynandromorph birds have been studied, and they are, indeed, half-male, half-female. They have an ovum on one side of their bodies and one teste on the other. Truly remarkable!

  48. Anonymous says:

    This bird proves a theory I have long held that opposes experts. In biology, students are taught that animals are color blind. If this is so, why does the male need to be bright red to attract a mate; and, why does the female need to be dull brown to be invisible to predators? It is a beautiful bird. Too bad it has not returned.

  49. jessie says:

    at first I said what? but after reading it is truly amazing. and pretty .

  50. Anonymous says:

    About 40 years ago I had a tall bird cage with about 5 pairs of finches in it...they were paired by name or something 2 of this kind and 2 of another...the pair of birds that were nun finches..the male had black and white markings and the female was drab and plain...he died and the female lost all her feathers and when the grew back she was marked like a male...very odd and a long long time ago...

  51. Anonymous says:

    It probably didn't return because it was afraid of nets!

  52. Anonymous says:

    They say once a Cardinal appears an Angel is near. I truly believe that. Now I'm curious what this could mean!! Soldier, Spirit Animal saying not matter the outside only the in. Or be comfortable in your own skin?

  53. I don't know anything about the genetics of birds, but really, Anonymous, polio comes from a virus and has nothing to do with genetics. I should know--I got polio when I was 6 and I'm 74 now.

  54. Well this was a very interesting read. Great information that I saved to look up. Especially the part of half male half female. Thanks for the article and also the pictures. Beautiful bird!!

Write a comment