Animal Rescue Cobh (ARC) asked me to do a homecheck in Bantry recently for a lovely pair of odd-eyed sisters. Passed with flying colours, the sisters will be going to their new forever home very soon! I thought I’d use the opportunity to share some info about odd-eyed cats – and home checks!
The kittens are especially gorgeous due to their unusual eyes. The technical term, heterochromia iridum, is a difference in colour in the iris (hence the name the Hi Sisters). Complete heterochromia refers to two different coloured eyes, like this pair. Partial heterochromia refers to different colours within the iris.
Either the white or the white-spotted gene is the usual cause of genetic heterochromia. These girls probably have the dominant white gene, which masks any other colour genes to make a completely white cat (the white spotted gene is responsible for bi-colour and tuxedo cats). Eye colour, specifically the colour of the irises, is determined primarily by the concentration and distribution of melanin. Both the white and the white-spotted genes prevent melanin (pigment) granules from reaching one eye during development. Kittens’ eyes change colour, if they’re going to change, at around 6 to 8 weeks old. So, since all cats have blue eyes when they’re born, it’s the blue eye that is the odd-eye.
Sometimes one eye may change colour following certain diseases or injuries, so if a kitten or cat older than ten weeks exhibits a change in eye colour, it’s time to visit the vet.
There is a common misconception that all odd-eyed cats are born deaf in one ear. This ain’t true – about 60%–70% of odd-eyed cats can hear. And about 10%–20% of normal-eyed cats are born deaf, or become deaf as part of the feline aging process. White cats with one or two blue eyes do, however, have a higher incidence of genetic deafness, with the white gene occasionally causing the degeneration of the cochlea, beginning a few days after birth. If a white kitten has any speck of another colour, the frequency of deafness is greatly diminished, even if the speck of colouration fades as the cat becomes more mature.
In flash photographs, odd-eyed cats typically show a red-eye effect in the blue eye, but not in the other eye.
And heterochromia iridum is not just a cat thing – some famous people with odd-eyes include: Dan Ayckroyd, Kiefer Sutherland, Christopher Walken, Michael Flatley and Alexander the Great.
So, to conclude, 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!
Some people can get unnecessarily intimidated by home checks, some don’t understand the point, some even get offended at the suggestion. I’ve already done a write up explaining the concept Why Home Check? so I won’t repeat it here.
Suffice to say, it’s important to realise that it’s not about you – it’s about being sure the companion you are thinking of adopting is right for you and that your home is right for her. It’s about what’s best for everyone.
I’d be very suspicious of anyone who strongly objects to a home check. No home check, no adoption. Hopefully, if you read my article, you’ll understand why.
- ARC (FB)
- Heterochromia iridum from Wikipedia
- Cats with Two Different Coloured Eyes
- Why Home Check?
- Homechecking Galleries