intersex kingdom

Meet Koko, The Female Horse With Testicles

We hate to fall into gender binary bullshit, but it’s a fact that male and female horses act differently. For example, stallions tend to buck trainers, urinate on other horses’ feces, and mount mares. Female horses, not so much. So it surprised horse owner Samantha Campbell when her mare Koko began acting like a stallion. She didn’t know WTF until she brought in a veterinarian to give Koko an ultrasound. The verdict: Koko has an internal set of testes. And she wasn’t the only one.

Campbell had another horse in her stables who acted a lot like Koko — it’s Koko’s younger sister, Sequoia. Both horses came from the same mother, a horse named Angel. So they tracked down another one of Angel’s offspring at a local ranch (a female foal named Pandora) only to discover that it was intersex as well. All three horses are sterile as they lack ovaries and a cervix, but their mother could continue to have intersex offspring, leading scientists to think that the feature is inherited on the X-chromosome.

We’ve heard of gay racehorses and have discussed the biology of hermaphroditic animals before. But this story ends with an interesting postscript.

Campbell had Koko and Sequoia’s testes removed. Since then Campbell says, Koko’s a changed horse. “Now she’s very docile, she’s a lovely horse, so much so that a friend’s daughter asked if she could work with her and take her into the local schooling show.” The removal of the Koko’s testes shouldn’t be seen as an anti-intersex act. After all we remove the testicles of other animals to make them more docile all the time. But it makes you wonder why Campbell made the decision and how Koko’s life might have played out had she kept her God-given testicles.