Cats with one blue and one green or yellow eye are striking. How does that happen? And is it true that odd-eyed cats are deaf in one ear as well?
What causes a cat’s eyes to be two different colors? Complete heterochromia, a condition where a gene suppresses the full color of pigment from developing so the result is two colors. It’s a common misconception that the cat will be deaf in one ear—the same side as the odd-colored eye.
“I was looking at the rescue cats at PetsMart. They had a beautiful white odd-eyed cat, absolutely stunning. If I didn't have my two, I would have seriously considered adopting her. She was totally deaf,” says Catkiki. “Later, I talked to the rescue person. She said that a couple of older ladies looked at the cat. One of the ladies was deaf herself. When she found out that cat was deaf too, she immediately adopted her!” This cat’s deafness was more likely a result of being white than being an odd-eyed cat.
Basically, the white gene or white spotting gene (even if there’s no white fur seen on the cat), can prevent melanin pigment granules from reaching the eye during development. Since all cats have blue eyes when they’re born, it’s the blue eye that is the odd-eye. In most cats, the adult eye color will show in under a year although in some purebreds, it can take as long as four years to learn the true colors. To tell the difference between green and blue, sometimes the human needs a little extra light. Then, of course, the pupil dilates and the human is still “in the dark” about the cat’s eyes. Odd-eyes can also be called bi-color eyes—one blue eye and one green, gold or brown—the paler blue eye is the eye that was blocked.
“Bi-colored eyes makes a cat different and unusual. It gives cats character,” says Aimee Gilbreath, executive director of Found Animals, a California based animal welfare organization. As with the white cat above, being different can also help a cat get adopted—everybody loves a good story to tell about their cat. Purebred cats like the Turkish Van and Turkish Angora are among the breeds that are prone to odd-eyed colors.
While this could be a fault in dog conformation, in cats, it’s considered a plus. In Turkey, the Ankara Zoo and the Turkish government, work to breed odd-eyed cats and have since 1917. They are considered a national treasure. Mohammed’s Traditional Turkish Angora was reported to have one blue eye and one gold eye. It’s said that he regarded the cat so highly that when it fell asleep on the sleeve of his robe, rather than disturb the cat, he cut his sleeve off.
The Japanese Bobtail cat often has the odd-eyed effect. The combination of extra-large tufted ears and striking eyes makes the cats so beautiful in person. In photos, the green eye shows green but the blue eye has camera “red eye” and makes for a scary photo.
The odd-eyed effect is not a disease or a symptom but a genetic quirk so don’t hesitate to adopt if you are lucky enough to fall in love with one.
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