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Are all white cats deaf?

Are all white cats deaf?

 

white cat

The short answer to this seemingly simple question is no, not all white cats are deaf. And, in case you were wondering, not all white cats with blue eyes are deaf either.

 

But there are very few truly simple questions when it comes to cats.

 

For starters, not every white cat is the same kind of white. Crazy, right? But there are at least three ways, genetically speaking, for a cat to be born completely white, and not all of these ways carry an equal risk for deafness.

 

There’s more than one kind of blue eye, too, for that matter.

 

Let’s talk about white cats!

 

What is a white cat?

 

I know this sounds like a trick question. But it’s important to explain that a white cat is entirely white with no other color markings at all. Not a hair.

 

White cats have pink toe beans and pink nose leather. A white cat’s eyes can be blue, green, copper, golden, or pinkish, and white cats can have odd eyes – also called heterochromia – meaning that one eye is one color, and the other eye is a different color.

 

What breed is a white cat?

 

white cat

A white cat is not a breed of cat. Whiteness is just a coat color, and in the case of a solid-white cat, it’s a pattern, too. A solid-colored cat of any color is described in the cat-fancy world as “self.” A solid-white cat is, thus, a self-white.

 

Many breed registries permit self-white cats. These include the American Curl, American Shorthair, British Shorthair, Cornish Rex, Devon Rex, Japanese Bobtail, Maine Coon,

Norwegian Forest Cat, Oriental Shorthair, Persian, Scottish Fold, Siberian, Sphynx, Turkish Angora, and Turkish Van.[1]

 

Are white cats friendly?

Because white is just a coat color, and because the genetics that cause white fur can vary between cats, there is likely little to no relationship between a cat’s white fur and his personality.

 

A white cat’s personality is more likely to be related to her underlying breed or combination of breeds, and her upbringing and life experiences, than to her coat color.

 

white cat

That didn’t stop people surveyed by the University of California, Berkeley in 2012, however, from assigning various personality traits to cats based on the color of their fur. In the survey, respondents were more likely to grade white cats as more antisocial, more shy, lazier, and calmer than cats of other colors.[2]

 

The goal of the study was not to prove that white cats really are more antisocial (or shy, lazy or calm), but just that people believe that they are, which ultimately affects their adoption rates at shelters.

 

How do white cats become white?

 

We know of at least three ways that a cat’s genes can produce fur that is all white. It is likely that there are other genes that contribute to whiteness that we just don’t know about yet. But understanding even the basic genetics behind a white cat’s whiteness can help determine whether your white cat is more or less likely to be deaf or hearing impaired.

 

Testing a white cat’s genetics is also important for breeders, because knowing the genes a cat carries is critical to safe breeding. No responsible breeder would want to unknowingly produce deaf kittens.

 

Albino white cats

 

Albinism is the absence of color. Albino cats appear white because their skin and fur do not produce pigment.

 

albino kitten

Albino cats can have blue eyes, or they can have blue eyes with a pinkish tint. The reason the eyes of an albino cat appear pink is that the genes that cause a cat to be albino also affect the structure of the shiny mirror at the back of the eye called the tapetum lucidum. The eyes of an albino cat reflect red/pink instead of the usual green.[3]

 

An albino’s eyes are often sensitive to light. If you have an all-white cat with blue eyes that seem sensitive to light, it is likely that the cat is an albino.

 

(Read more about cats’ eyes in, “Can cats see in the dark?”)

 

Albino and Siamese cats have something in common

 

siamese cat

Interestingly, albinism is, genetically speaking, an extreme form of colorpointing. Colorpointing is the kind of coat pattern that Siamese, Tonkinese, and Burmese cats have, in which their “points,” or extremities, such as the face, legs, and tail, are a darker color than the rest of their bodies.

 

Siamese and other colorpointed cats get their magnificent ombre tones from a mutation in the TYR gene. This mutation causes the enzyme responsible for fur color to work only at cooler temperatures.

 

Colorpointed kittens are born white because it’s warm inside their mothers’ womb, so the pigment enzyme doesn’t kick in. After the kittens are born, they begin to get progressively darker at the cooler “edges” of their bodies.

 

Albino kittens are the result of a more extreme and very rare mutation in the TYR gene that causes their bodies to produce very little, if any, color at all.

 

True albino cats are very rare

 

siamese kitten

Albino cats are extra rare because the albino gene is recessive to all the other color genes. For this reason, the albino type of white cat is sometimes called “recessive white.”[4]

 

It also means that for a kitten to be an albino, he has to get two of these rare albino genes, one from each of his parents.

 

This mutation is so rare, that among 9229 tested by the Veterinary Genetics Laboratory at University of California, Davis, only 4 cats tested positive for the albino mutation.[5]

 

Albino cats are very unlikely to be deaf

 

Deafness is extremely rare in non-white cats. If you have a cat who isn’t white, but happens to be deaf, it is most likely due to an illness or injury that occurred after the cat was born.[6]

 

Since albinism results from a different mutation than the one that causes most white cats to be white, it has no known impact on hearing.[7] Albino cats, like non-white cats, are very, very unlikely to be deaf.

 

Dominant-white cats

 

white cat

The most common way for a cat to be born white is for it to carry a dominant-white gene.

 

Unlike the gene for albinism, however, which causes the absence of color, the dominant-white gene overrides a cat’s “real” color. It covers the other colors with whiteness.

 

Genetics has a word for this phenomenon: epistasis. Epistasis is when one gene is disabled by the presence of another. Dominant white is an epistatic gene.

 

For example: a cat could have two dominant black genes, one from each parent. This same cat could also have two non-dilute genes, which tell the fur to be deep, dark black, rather than gray. But if this cat also has a single dominant-white gene, the cat will actually be solid white.

 

I told you cat color genetics are complicated.

 

Remember that I also said that a white cat has no colored hairs? Well, some dominant-white cats are actually born with smudges of color, usually on the top of the head. This is because their dominant-white genes didn’t work 100% at covering the cat’s underlying color. But any smudges usually disappear by the time a kitten is full-grown.[8]

 

White-spotted cats

 

black and white cat

Cats, and many other animals for that matter, including humans,[9] can carry a gene for white spots, called, conveniently enough, the white-spotting gene. We also sometimes call animals with white spotting, “piebald.”

 

Cats of another color who happen to have some white fur on them, usually have the white-spotting gene. Tuxedo cats have the white-spotting gene. A calico cat is a tortoiseshell cat with the addition of the white-spotting gene.

 

Some cats with the white-spotting gene might only have a little splotch of white at the tip of the tail, while other cats are almost completely white, with just a little color on an ear. Both extremes are examples of white spotting.

 

It’s believed that a white-spotted cat with a lot of white has two white-spotting genes, one from each parent. A cat with white spots that cover less than half of her body likely has only one white spotting gene (plus a “non-white-spotting” gene).

 

In fact, a cat who is completely white with no color at all could actually have the white-spotting gene, not the dominant-white gene. It can be hard to tell if a cat is “dominant white” or just extremely “white spotted” without a genetic test.

 

A few fun facts about white-spotted cats

 

cats with odd eyes

If a cat’s nose or paws are white, it is likely that his nose leather will be pink.

 

If a cat’s eye is covered by a white patch, the eye is most likely to be blue.

 

Cats with odd eyes are almost always white or have white spots.[10]

 

What does a white coat and blue eyes have to do with deafness?

 

White cats with blue eyes are prone to deafness. But since a white coat and blue eyes can be caused by different genes, not all white-coated, blue-eyed cats are deaf or have hearing loss.

 

It’s worth stating again: albino white cats with blue eyes are no more likely to be deaf than a cat of any other color. The genes that cause albino cats to have white fur and blue eyes have nothing to do with hearing.

 

What is the relationship between blue eyes, white fur, and deafness in some cats?

 

white cat with blue eyes

Most cats get their color when they are just embryos, developing inside their mothers. At some point in development, pigment cells, called melanocytes, move to the skin. These pigment cells will produce melanin for the rest of the cat’s life, and so the cat will remain a tabby, or a ginger, or whatever his DNA instructs, for the rest of his days.

 

But when a kitten with a dominant-white gene is developing, the pigment-producing cells don’t move to the skin. For kittens with a white-spotting gene or two, this happens in whatever areas of the cat’s body that will ultimately be white.

 

Eye color develops from the same stem cells as the melanocytes. So, sometimes one eye or both fail to get color, like the skin. We see these “colorless” eyes as blue. They’re not really blue, but they appear to be blue, due to a phenomenon called the Tyndall Effect.[11] The Tyndall Effect has to do with the way light enters the eye and scatters, and it’s the reason the sky looks blue to us, too.

 

These very same stem cells are also responsible for the development of a special cell layer in an embryonic kitten’s ear. The genes that cause white fur (except in the case of albinos) also prevent this cell layer from developing properly, leading to permanent hearing loss.

 

Blue eyes, by themselves, are not associated with deafness

 

siamese

As I mentioned above, the blue eyes that an albino cat has are not associated with deafness.

 

The blue eyes that Siamese cats have are not associated with deafness either.[12] Because albinism and colorpointing are genetically related conditions, it’s likely that a Siamese’s blue eyes are blue for the same reason an albino cat’s eyes are blue.

 

The number of blue eyes matter in white cats

 

Statistics show that the more blue eyes a white cat has, the more likely she is to be deaf.

 

“Only” 20% of white cats without blue eyes are deaf. This is likely because the eyes and the ears are so close to one another, especially in a developing kitten embryo, that if the eyes develop from stem cells that produce working melanocytes, the ears will develop from those same stem cells, too.

 

40% of white cats with one blue eye are deaf. In cats with two different colored eyes, the side with blue eye is likely to be the side with the deaf ear. Interestingly, many cat guardians are unaware that their cat is deaf in that one ear. Cats with hearing in one ear typically behave like a fully hearing cat.

 

70% of white cats with two blue eyes are deaf.

 

Cat genetics matter, too

 

white cat

As we now know, not all white cats come about their whiteness in the same way. Different mixtures of genes can produce different outcomes, especially with regard to hearing impairment or deafness. Two white cats should never be bred together without genetic testing.

 

Nearly all cats who have two dominant white genes, one from each parent, have some hearing impairment. 73% of cats who have two dominant-white genes are entirely deaf. For this reason, it’s important to never breed two cats who have dominant-white genes.

 

66% of cats who have one dominant-white gene and one white-spotting gene have some hearing impairment or are deaf.

 

“Only” 37% of cats who have one dominant white gene and one non-white-spotting gene have hearing impairment or were deaf.[13]

 

There are other genes likely responsible for whiteness and deafness

 

Scientists are studying coat color and deafness genetics in a variety of animal species. The idea is to understand which genes specifically cause deafness and use DNA tests to identify the animals that are carriers of these mutated genes. Hopefully, with more knowledge, we can reduce the prevalence of deafness.

 

To date, scientists have studied multiple genes -- MITF, PMEL, KIT, ENDRB, CDH23, TYR, TRPM1, to name a few – in a variety of animals, including the cat, dog, horse, cow, pig, sheep, ferret, mink, camel, and rabbit, to try to track down all the genetic causes of deafness.[14]

 

Deaf white cats have been banned from some cat shows and registries

 

cat show ribbons

In an effort to reduce or eliminate the deafness trait, some cat fancy organizations in Europe have banned deaf white cats from exhibition or breeding.

 

According to the rule of the Governing Council of the Cat Fancy, a British breed registry, any breed of white cat must pass a hearing test before being registered.[15]

 

Does this seem unfair to you? Even prejudiced?

 

Deaf cats make for wonderful companions and I’m certain that anyone who has a deaf cat would never have him any other way.

 

But deafness is a trait that can cause problems for the cats themselves. Deaf cat mothers are unable to hear their kittens crying and may inadvertently neglect them. Deaf kittens are unable to hear their mother calling for them and may get separated. Adult deaf cats can’t hear predators, cars, and other dangers approaching. Some deaf cats meow overly loudly because they have no sense of volume.

 

I, for one, applaud these breed registries for taking a stand in the best interest of cats.

 

Love Pinterest? Here's a Pinterest-friendly pin for your boards!

 are all white cats deaf?

  

DAwn and Timmy
Dawn LaFontaine

Dawn LaFontaine is a lifelong animal lover who always seems to have a little pet hair in her keyboard. Her blog, Kitty Contemplations, helps cat guardians better understand and care for the special beings they share their lives and homes with. Her cat-products business, Cat in the Box, sells beautiful, well-made, and award-winning products that she designed to meet the biological needs of cats.

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FOOTNOTES

[1] “Meet the White Cat Breeds.” Petfinder, https://www.petfinder.com/cat-breeds/collections/white-cat-breeds/.

 

[2] Anwar, Yasmin. “Don't Be so Fast to Judge a Cat by Its Color, Study Warns.” Berkeley News, 21 July 2015, https://news.berkeley.edu/2012/10/23/cat-color/.

 

[3] Hartwell, Sarah. “WHITE CATS, EYE COLOURS AND DEAFNESS.” White Cats, Eye Colours and Deafness, http://messybeast.com/whitecat.htm.

 

[4] ibid.

 

[5] “Albino.” Albino | Veterinary Genetics Laboratory, https://vgl.ucdavis.edu/test/albino-cat.

 

[6] Care, International Cat. International Cat Care, 6 Oct. 2019, https://icatcare.org/advice/inherited-deafness-in-white-cats/.

 

 

[7] “Dominant White & White Spotting.” Dominant White & White Spotting | Veterinary Genetics Laboratory, https://vgl.ucdavis.edu/test/dominant-white-cat.

 

[8] Hartwell, Sarah.

 

[9] Spritz, Richard A., and Vincent J. Hearing. “Abnormalities of Pigmentation.” Emery and Rimoin's Principles and Practice of Medical Genetics (Sixth Edition), Academic Press, 29 Mar. 2013, https://www.sciencedirect.com/science/article/pii/B9780123838346001543?via%3Dihub.

 

[10] The Little Carnivore. “Cat Coat: White Cats and White Spotting.” The Little Carnivore, The Little Carnivore, 26 Oct. 2021, https://thelittlecarnivore.com/en/blog/cat-coat-white-cats-deaf-white-spotting.

 

[11] MacDonald, Fiona. “This Is the Fascinating Way Blue Eyes Get Their Colour.” ScienceAlert, 2 Jan. 2018, https://www.sciencealert.com/science-how-blue-eyes-get-their-colour.

 

[12] Strain, George M. “The Genetics of Deafness in Domestic Animals.” Frontiers, Frontiers, 1 Jan. 1AD, https://www.frontiersin.org/articles/10.3389/fvets.2015.00029/full.

 

[13] The Little Carnivore.

 

[14] Strain, George M.

 

[15] “Baer Testing for White Cats.” The Governing Council of the Cat Fancy, 30 Mar. 2022, https://www.gccfcats.org/breeding-cats/new-to-breeding/testing/baer-testing-for-white-cats/.

 

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