Cat With White Fur and Robin Blue Eyes
- Lifestyle
Siamese Cats Are Temperature-Sensitive Albinos, a.k.a. Walking Heat Maps
- By Lisa Richman
- , January 5, 2018
If my cat wore socks, his fur would change color. No, seriously. It really would. And I have the pictures to prove it. Okay, maybe not of him in socks. Because that's just not going to happen. Ever. But I really could get his fur to change color. And anyone owned by a Siamese could do the same thing. It's all thanks to a special gene they have in common: an albino gene. What? Wait. Siamese aren't albinos. Actually, they are.Temperature-sensitive albinos.
When we think of an albino, we usually think of someone without pigment. But Siamese — and similar breeds — aren't stark white, so what gives?
Siamese are temperature-sensitive albinos because of genetics
See, a cat's coloring is determined by a set of eight different genes. They're what tell a black cat to be black, or an orange cat to be orange. And then there are modifier genes — these can cause a cat's fur to be patterned in a certain way, or mask the color altogether, like you'd see in the white bib-and-spats on your classic tuxedo kitty.
But Siamese and similar cat breeds have a special modifier gene called a Siamese allele that mutates the color gene. It inhibits pigment — in other words, it causes albinism.
But that modifier signal only gets through to a kitty's fur if it's above a certain temperature.
So, how does this gene work?
This modifier starts sending out its "stop the color!" message around 100.4-102.5 F (38-39.2 C), which is a cat's standard body temperature. Anything lower than that and the mutation is blocked and the color gene can then do its color thing.
Because a cat's body is cooler around his ears, paws, and tail, that's where the color begins to kick in. In essence, these cats are walking heat maps. Kinda cool, huh?
Why are these cats born lighter and then darken as they age?
It's pretty warm in the womb, so all kittens with this special modifier allele are white throughout gestation. They pop out as white kittens too, but once exposed to atmosphere, their extremities begin cooling.
Once they hit that critical temperature, those alleles that have been inhibiting the enzyme responsible for pigment turn off and color begins to develop — on the ears, paws, tail, and face.
Someone questioned why the face — that's not an extremity. True, but we have a lot of holes in our faces: eyes, ears, nose, mouth (the same argument my dad used when I was a kid and wanted to pierce my ears: "You don't need another hole in your head!"). All those cavities in the head account for enough of a drop in temperature to let the color kick in.
Notice this kitten's nose is darkest? Big breathing holes there! And at this stage, his paws are just beginning to get their dark brown color.
So, let's think about temperature-sensitive albinos for a sec
If all it takes to make these cats "go albino" on you is to increase their temp, what if you made a cat wear socks? Would his paws turn white?
First, good luck with that experiment. Be sure to let me know how that works out for ya, 'K?
Seriously, if you could actually keep them on him, then, well, the answer is yes. Because coat color is lightened by high body temperatures and darkened by lower temperatures, a bandage covering the fur — or even cold weather — can alter the color.
One of my cats — a Tonkinese — had to have a four-inch swath shaved around his lower abdomen for a sonogram a few years back. It happened right before we entered one of the coldest winters on record. His fur grew back a shade darker. Fortunately, as spring turned into summer, his coat lightened once again.
But wait — the temperature-sensitive albino genes get even weirder…
There are actually two temperature-sensitive albino genes, and one of them is a bit more lazy than the other. The Siamese allele is the more efficient one, and cats carrying this have those pointed coat patterns we associate with the breed. The less efficient one was found in the Burmese cat, and therefore bears its name.
This makes total sense if you look at pictures of both breeds. Siamese have the most contrast whereas Burmese can sometimes have very little contrast. That's why many Burmese — and some Tonkinese — aren't described as pointed cats (such as seal point or blue point). They're known as minks instead.
See how little contrast our guy has in the photo below? He's considered a mink, not a point.
OK! Done with the hard science. Back to the cool stuff.
What if a Siamese cat didn't have that modifier allele?
If you ignore the temperature-dependent albinism thing going on, genetically my Maxwell is a solid grey kitty.
And a sealpoint Siamese? Well, genetically that's a black cat, only with alleles.
Interesting to think about, no?
Thumbnail: Photography ©studdio22comua | Thinkstock.
Read more about cats and science on Catster.com:
- What is a Cat Flehmen Response?
- What It Means to Be a Tabby Cat
- The Fascinating Facts Behind Cat Colors
Read more about Siamese cats on Catster.com:
- Who's That Cat? The Siamese, if You Please
- Did You Know Siamese Cats' Eyes Explain Why the Sky Is Blue?
- Silver Belle, a Senior Siamese Cat, Gets a Second Chance
About Lisa Richman: Writer, director, pilot, foodie, cat person. When she's not on set, this director of film and video can usually be found taking photos of cats (and food) with her trusty Nikon, or cruising aloft at 3,000 feet. She's cat mom to an opinionated Tonkinese, a hearing-impaired Siamese, and a feline fashionista. She's also the owner of a recently launched food blog, and the Cat Writer's 2014 Entertainment Blog, A Tonk's Tail.
- Tags: Breed Profiles, Breeds, Cats And Science, Offbeat, Stranger Than Fiction
23 thoughts on "Siamese Cats Are Temperature-Sensitive Albinos, a.k.a. Walking Heat Maps"
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Source: https://www.catster.com/lifestyle/cat-facts-genes-siamese-cats-temperature-sensitive-albino
People can have this gene too! It's called oculocutaneous albinism 1B in humans if I remember correctly.
I am so THANKFUL I finally found this article!! Thank You!! My new Siamese, Vega, came with some unresolved issues when I got him at 8 months old. He licked a spot bald to raw and now that the fur seems to be growing back, the area looks BLACK & I was so worried but apprehensive to go to the vet AGAIN afraid of what I would find out. Relief!! Yippie! He is fine & it's normal Siamese genetics!! So happy!! And saved me a trip to the vet (and the stress to Vega) for nothing.
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kudos for this article
I have a 3 and a half-year-old Siamese, for the longest time she had a gorgeous cream color covering her body is a seal point. She looks almost exactly like the first photo except she has a darker face. I have a story about her coat changing nearly completely, except for her points. (Skip next paragraph if you don't care about why it happened.)
We regularly let her outside to roam and be with us when we are in the yard. One time we let her off the leash. My girl was around 1 and a half to nearly 2 years old at the time. I left her outside with her "Dad" or my fiance, while he was doing some body work on the car while I did a very quick errand. It was probably less than 20 minutes. Well, my fiance saw her jump the fence and go to the alleyway, which is busy since there's a gas station 2 houses down. He was working with Bondo or a body filler substance. He had it all over his hands when he scooped up the cat and set her back safely in the yard. I came back to a cat that was foaming at the mouth, throwing up, unaware of what had happened. Scariest moment of my life. Immediately went to the vet, only then noticing she was covered in Bondo. We called the maker of the stuff, but they couldn't give us trade secret information on what exactly it contained. The vet watched her and deduced that she most likely got all the Bondo she ingested out of her body when I first found her. The vet decided to shave off the parts where the Bondo was. After the vet techs fought her, I immediately went to calm my baby and save the tech's from her wrath, she was shaved in various lengths just to get the Bondo off.
We went home with a cat shaved in various lengths but healthy, and still beautiful. Her hair looks choppy and uneven so I decided to shave most of her body down to one length so it doesn't look funny. She complies and lets me do it probably because she hated the different lengths too. This was mid-October, in Minnesota, so the weather varies day to day. Due to this colder weather, she is now a dirty, sand color, on the majority of her body, and where the blades got closest to her skin a chocolatey brown. I can tell exactly how her "Dad" grabbed her since the pattern of the darkest points on her outlines the diameter of his hand and fingers. The only part where she is still that cream color is between her armpits and a little going down her throat to her chest.
I still adore my cat and think she has a gorgeous face but I really miss her beautiful cream color. I consider shaving her again, to test if I can get her back to her other color but am unsure if I should. Her undercoat/ coat is still that cream color, then turns to the darker colors. Would shaving her in the summer be a better idea to change her back since the gene is temperature sensitive? Also since siamese cats coat colors can change naturally as they age, would this impact her since I've waited for so long? I'm torn since I know my cat will let me shave her, but I do not want her to get any darker, she may just look like a chocolate brown cat and not a more "traditional" coloring pattern.
I'd like opinions to figure out what could get her to go as close to her original color as possible, or at least lighter on the extremely dark parts of her back/hips.
Wow, thanks for sharing!
i've noticed my nearly 17 year old siamese kitty's right paw was getting lighter and lighter over the past few months. after reading this article, i went to check how she was sleeping – right paw tucked under, left paw out. i bet she's being sleeping consistently like that for a little while now!
neat!
I love that yours is 17! I know Siamese cats usually live longer than other cats, I had one that live to 20. My girlie now is 14.
I have seen this before with Siamese cats and their fur being heat sensitive a bit, it's pretty cool. Siamese are truly the best cats there are, and I love the face of the one at the top of this article!
Wow !! love to see this post :)
I got siamesse cat 1 year old. Never been outside, lived inside apartment all life. He was dark brown. After he came to my house with big backyard he start to spend a lot of time outside. In few month he became light beige… And I was wondering why.. Now is all clear. His body did not have enough circulation since he was inside small apartment, only sleeping and eating. So this is 100% true.
Brittany, the blue color of the eyes are from reflection of light. When my Siamese turns her head in different positions, I can see the pink color. It's really intriguing.
The case of the missing pigment
"Do you have any idea why one side of Toppy's face has lost its color?" On an annual visit several years ago, I asked my vet this question and he had no idea.
I have a great picture of this and would be glad to include it but it does not paste into this comment box.
When I first noticed this, I felt around his face to see if there was any kind of growth and could feel nothing.
Several years after that, my new vet came up with the answer: Toppy is a chocolate point Siamese.
As a geneticist and a biology professor I understood.
As described in the article, Siamese cats are temperature sensitive albinos. (I study very different genes, but they too are temperature sensitive).
The gene needed to produce skin, hair and eye color codes for an ENZYME needed to make the pigment melanin.
The enzyme produced from Siamese gene is defective and does not function in areas of the cat that are warm, such as the main part of the body.
Because the color point areas are cooler, at these locations, the enzyme is in good shape and can make pigment.
There was an area on the right side of his face that didn't have pigment and in this location, the enzyme must not be functional.
How did we figure this out?
Well, Toppy had really bad breath and our new vet said we should get his teeth cleaned and that he had some badly infected teeth that had to be pulled.
After the operation, we brought him in several times to have the wound checked. The next-to-last time, the vet said we could take a photo of his mouth and email it to her. So I asked her which side. We looked at him in the carrier and realized it was the side of his face that was white.
That's when the lightbulb went off for the vet and for me.
We hypothesized that the infection had raised the temperature of his face just enough to lead to production of a non-functional enzyme.
And if that was the case, over time his pigment should return, but it would have to wait until he made all new fur in the area.
This is because once a bad enzyme is synthesized, it cannot recover and he would need to synthesize the new enzyme in each new hair.
It took about 3 months, but he finally looks like a normal, symmetrical Siamese cat again.
Yes, exactly! The modifier I mentioned is the enzyme that the gene codes for, and at certain temperatures the enzyme is produced, changing the color.
How fascinating that the side of Toppy's face changed color. What an excellent example of this in play. Poor little guy, that must have been quite the infection he had in his teeth.
Yes, we noticed the same thing — well, kind of the opposite, actually. Where our Tonk was shaved, well…his shaved belly fat and the cold winter days (we suspect) were what kept his skin cool enough for the enzyme to synthesize. Once summer hit, the enzyme was once again blocked and his new fur grew in light once again.
Thank you so much for sharing!
I have a 3 and a half-year-old Siamese, for the longest time she had a gorgeous cream color covering her body is a seal point. She looks almost exactly like the first photo except she has a darker face. I have a story about her coat changing nearly completely, except for her points. (Skip next paragraph if you don't care about why it happened.)
We regularly let her outside to roam and be with us when we are in the yard. One time we let her off the leash. My girl was around 1 and a half to nearly 2 years old at the time. I left her outside with her "Dad" or my fiance, while he was doing some body work on the car while I did a very quick errand. It was probably less than 20 minutes. Well, my fiance saw her jump the fence and go to the alleyway, which is busy since there's a gas station 2 houses down. He was working with Bondo or a body filler substance. He had it all over his hands when he scooped up the cat and set her back safely in the yard. I came back to a cat that was foaming at the mouth, throwing up, unaware of what had happened. Scariest moment of my life. Immediately went to the vet, only then noticing she was covered in Bondo. We called the maker of the stuff, but they couldn't give us trade secret information on what exactly it contained. The vet watched her and deduced that she most likely got all the Bondo she ingested out of her body when I first found her. The vet decided to shave off the parts where the Bondo was. After the vet techs fought her, I immediately went to calm my baby and save the tech's from her wrath, she was shaved in various lengths just to get the Bondo off.
We went home with a cat shaved in various lengths but healthy, and still beautiful. Her hair looks choppy and uneven so I decided to shave most of her body down to one length so it doesn't look funny. She complies and lets me do it probably because she hated the different lengths too. This was mid-October, in Minnesota, so the weather varies day to day. Due to this colder weather, she is now a dirty, sand color, on the majority of her body, and where the blades got closest to her skin a chocolatey brown. I can tell exactly how her "Dad" grabbed her since the pattern of the darkest points on her outlines the diameter of his hand and fingers. The only part where she is still that cream color is between her armpits and a little going down her throat to her chest.
I still adore my cat and think she has a gorgeous face but I really miss her beautiful cream color. I consider shaving her again, to test if I can get her back to her other color but am unsure if I should. Her undercoat/ coat is still that cream color, then turns to the darker colors. Would shaving her in the summer be a better idea to change her back since the gene is temperature sensitive? Also since siamese cats coat colors can change naturally as they age, would this impact her since I've waited for so long? I'm torn since I know my cat will let me shave her, but I do not want her to get any darker, she may just look like a chocolate brown cat and not a more "traditional" coloring pattern.
I'm an undergrad biotech student with a real interest in genetics and would love your opinion on how I should best conduct this "experiment".
Hi there,
Thanks for reaching out! We suggest asking your vet about this. We don't suggest shaving your cat unless it's for medical reasons.
https://www.catster.com/lifestyle/is-shaving-your-cat-okay
Fascinating! Can the opposite be true also? I noticed this year when my 1 yr old siamese (thought he was a sealpoint blue eyes) spent more time outside, when it got warm, his back, sides, face have gotten darker! It's been a lot hotter this year. He was always a light creamy color, with grey/dark grey markings (ears, nose, lower legs, etc. His tail has some faint stripes on it. His neck (under his face) and tummy side are still light creamy colored. Will his coat lighten up again when it gets cold out?
Thanks in advance.
Cathryn
Interesting, however, the photo of the cat with the shaved patch and regrown fur shows two different sides of the cat. Not the most convincing photographic evidence for me.
Plus, the dark hairs on the back and belly are guard hairs so when shaved it would only show the white under coat. I'm pretty sure this article is bunk.
Brittany, please feel free to click on any of the links in the article, as these constitute the bibliographic evidence to support the topic.
In case you weren't aware, a link in this article is denoted by the orange-colored text.
You'll notice that, as you hover your mouse over the text, your cursor will indicate it is clickable.
Happy reading, and we hope we have expanded your cat knowledge today!
And albinos have pink/red eyes. Blue eyes on white animals are leusistic, not albino.
I've owned temperature sensitive albino leopard geckos, and they don't change color like a mood ring, but get dark one they get cold, and no amount of warmth will bring back their vivid coloring.
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