Blue eyes in cats are among the most popular purebred traits. The popularity of pointed cats, like the original Siamese and the extension of the pointed gene onto Ragdolls and Himalayan Persians like Calpurnia is partly due to the blue eyes that come with it. Pure and nearly pure white cats also have an increased chance for blue eyes, although in this case deafness is often an undesirable side-effect.
In order to produce blue eyes, the same pigment forming cells that color the cat’s fur must be blocked when forming the cells of the eye. Higher levels of pigment produce yellow or green eyes. Young Kittens have blue eyes because the eyes are not fully developed.
Can you have a cat with a ‘normal’ coat and blue eyes?
There have been reports of a spontaneous mutation that does this that was given the name ‘Ojos Azules’ – Spanish for blue eyes. It seems to not be related to any of the other mechanisms for producing blue eyes. Oddly, for such an interesting phenomenon, finding pictures of these cats is very difficult. Finding pictures of cats with photoshopped blue or purple eyes is easy, however. I found a Flickr picture of a black cat with blue eyes. It is a nice shot, but the eyes look a little ‘off’. Looking at other pictures in the set, I found two other pictures of a black cat, but the eyes are yellow. So odds are this was a filtered picture for effect. And to be fair, the photographer does not claim this cat is genetically unusual, even if the commenters are.
Apparently, some breeders tried to make a new breed out of some stray Ojos Azules cat they found in New Mexico, but ran into a problem. Apparently it is a dominant gene but if a cat inherits two of them, some fairly massive deformities result that kill the cat. This is another indication that this is a new gene, as the various White and Pointing genes have no such effect. This led to the breeding program being shut down. Unless there is a reason to think the ill effects can be removed, having some kittens with blue eyes hardly seems worth having so many die or inherit major deformities.
Julius popped out front this evening in the twilight and just outside the front door there were at least two large rabbits on the lawn area.
I’m not sure he even saw them, and they took off when he stepped on a fallen leaf and made a sound. He didn’t react even when they ran, which makes it more likely he never detected the fellows.
He didn’t stay out too long before coming around back to get inside again. It isn’t as noisy as the first night but there is still some wind, and the piles of litter all over the area probably made him a little less comfortable strolling around.