''Cervus canadensis'' - antlered female - seeking thoughts and opinions

I spotted this animal in May 2014 in Tusayan Arizona, near the south entrance to Grand Canyon National Park. It is obviously an elk (Cervus canadensis), and it appears to be a female. However, it clearly has a pair of well-developed antlers.

To my knowledge, the reindeer (Rangifer tarandus) is the only cervid species in which females normally grow antlers. I am aware of rare cases of antlered female white-tailed deer (Odocoileus virginanus), but I have not seen anything like this anywhere else, including a fairly extensive search of the internet.

This does not appear to be an example of gynandromorphism, which to my knowledge has not been described in mammals. It might be an example of chimerism or mosaicism, but my guess is that this cow simply has an increased serum testosterone level.

Just seeking thoughts and opinions from the illustrious members of the iNat community regarding this unusual observation. :blush:

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I’m no expert, but where I live Cryptorchid deer aren’t too uncommon, so I think it could happen to elk too. I believe antlered females have been also been recorded for deer and other members of their family.

I saw quite a few posts on Facebook of shot deer with genitals of a female and antlers, so it’s certainly possible. Looks like those are true hermaphrodites.

Gynandromorphism does occur in mammals, but is rare. It’s mostly just been documented in lab mice (and humans if you include various intersex conditions).

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See this link for a discussion of this phenomenon.

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You are absolutely correct to say that among the Cervids only female reindeer normally grow antlers.
It happens occasionally among deer here in the UK, most usually roe Capreolus capreolus, almost inevitably concerns older animals and is linked to abnormal hormone production. Old females developing pedicles are very common, and some go on to produce small antlers which are never cleaned of velvet (this process depending on sufficient testosterone production). Only very, very rarely does cleaning occur.
I also received pictures last week from a hunter who had shot a Reeves’ muntjac Muntiacus reevesi which had the normal head of a mature male but female genitalia - I did not have the opportunity to examine it but was assured that there were no testes of any size within the body. A vet friend who specialises in deer tells me that he has seen it occasionally in roe deer, only sporadically in red deer Cervus elaphus but only very very rarely in muntjac.


What characters are being used to determine if this is a cow or bull?

I’ve heard only one eyewitness account and evidence of this once. An old hunter I was visiting with as part of a camp field trip was describing his trophies and he had one which at first glance looked out of place (compared to the massive specimens he had on display), a spike mule deer. He said “you might wonder why I bothered to have that mounted” - turned out after he shot it and was cleaning it he realized that it was a female with antlers and not a spike mule deer. That was the first and only time I had heard/seen evidence of antlers on a female cervid that wasn’t a reindeer until this picture. Nice catch!

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Menopause is not abnormal.

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But it’s not menopause, it’s too much male hormones being produced, antlers can’t be explained by lack of female hormones alone.

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