If you have a black cat, there’s a chance you may have noticed your cat’s coat change from black to a brown or reddish color. It may happen all over or just in certain spots. There are a few different things that can cause a black cat’s coat discoloration, and thankfully the most common ones aren’t cause for too much concern.
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1. Sun Exposure
You know how human hair can lighten in color if we spend too much time in the sun? The same holds true for cats. If a cat spends a lot of time outdoors or laying in sun-puddles, the color of their fur can lighten too. No big deal.
2. Diet
Tyrosine
Cats require 22 amino acids. 11 of these are essential, meaning they MUST be consumed in their diet. The other 11 are non-essential, meaning they can be synthesized and are not needed in their diet. Tyrosine is a non-essential amino acid synthesized from the essential amino acid phenylalanine. Tyrosine is also required to produce melanin, which is responsible for the pigment of your cat’s skin and coat color.
If your cat is not getting enough tyrosine, then they aren’t going to produce as much melanin. This results in a brown/reddish coat color instead of pure black. On the flip side, adding more tyrosine to a cat’s diet can reverse the discoloration, and can even turn a naturally brown cat’s coat more black.
However, according to a study done at the University of California Davis, the current amount of phenylalanine and tyrosine recommended for normal growth and health is not enough to maintain maximal melanin production for a fully black coat color. Therefore, your black cat having a brown or reddish tint to their coat does not necessarily mean that anything is out of balance in their diet. Though, this begs the question – are the current dietary recommendations for these two amino acids high enough?
Sources of tyrosine: Since tyrosine is synthesized from phenylalanine (found in proteins), feeding a diet higher in protein can help to increase production of tyrosine. Tyrosine can also be supplemented into the diet directly. Please consult with your vet before adding any supplements to your cat’s diet.
Copper
Copper is an important mineral required in a cat’s diet, involved in bone and connective tissue development, hair pigmentation, and iron absorption. Copper deficiency is extremely rare, but it can cause a discoloration in a cat’s coat color. It is also usually accompanied by other symptoms, such as anemia, ataxia, and coat texture change.
Sources of copper: Copper is found in liver and fish, though most quality cat food is adequately supplemented with copper.
Zinc
Zinc is another essential mineral, important for healthy skin and coat, as well as for immunological and inflammatory processes. Consuming too much zinc, known as zinc toxicity, can cause a copper deficiency (see above). Other symptoms of zinc toxicity include lack of appetite, vomiting, diarrhea, lethargy, and more. Zinc toxicity can be fatal, so if you suspect your cat has ingested too much zinc, please see a vet right away.
3. Illness
Another cause for a black cat’s fur to change colors is due to thyroid, kidney, or liver issues. These organs all have some type of relationship with the amino acid tyrosine (discussed above). Tyrosine is metabolized in the liver and is also necessary for the production of thyroxin, a hormone produced by the thyroid gland. If either of these organs are not functioning properly, the required amount of tyrosine is most likely not being produced, resulting in a discolored coat.
Organ issues are much more serious that the other issues discussed above, though like the copper deficiency and zinc toxicity, they are usually accompanied by several other symptoms. Please see a vet if you suspect your cat’s organs are not functioning properly.
4. Age
Age can also play a role in your black cat’s coat color. As animals age, their coats may begin to fade, or they may start turning gray. This is a normal phase of life and isn’t anything to worry about.
In most cases, a black cat having a slight brown/red discoloration or having brown/red splotches isn’t cause for concern. Chances are your kitty has just been doing a little too much sunbathing or is simply not synthesizing quite enough tyrosine to keep their coat looking purely black. However, it is important to check with your vet to be sure that there isn’t a more serious underlying issue.
Sources and Further Reading:
The Journal of Nutrition – Red Hair in Black Cats is Reversed by Addition of Tyrosine to the Diet
The ASPCA – Cat Nutrition Tips
Spot the Difference – Using the Domestic Cat as a Model for the Nutritional Management of Captive Cheetahs
PetEducation.com – Copper Requirements in Cats
PetMD – Zinc Poisoning in Cats
This is such an interesting information! I had a black dog when I was a child, and she got a bit of brown when she got older. I have black hair and it’s getting brownish, too. I’m guessing age has a lot to do with that 🙂
That is really interesting. We learn new things evfurry day!
when sauce layed in de sun he looked brown…lotz oh hiz furz terned white ……N him waz still young !! ♥♥♥
This was very interesting. I’d heard about sunbathing, but not the other information.
So far Lexy’s fur hasn’t turned brown. This is good information for Mommy to remember.
My human had a black cat, a few decades ago, and he did turn brownish later in life.
I have a lot of black foster kittens that come in with brown fur.. I always assume it is Tyrosine deficiency
How interesting! I have never had a black cat and I had no idea their coats could turn brown. Great info to have going forward.
That really was interesting and we never thought about those things!
Zorro turns brownish every summer, and turns back to black in autumn. He loves sunbathing, maybe too much ! Purrs
Mine’s like that too. And now at 8 yrs old it becomes more and more apparent, during summer. His head stays (almost) black tho’. He absolutely loves sunspots…
Oh my word…this was most interesting.
That is very interesting. Our Spooky is actually much darker than when he used to roam the neighborhood before we adopted him.
This is interesting. All three of the black cats who were members of our family in the past became browner with age. But they all had thyroid issues, too.
My coat has turned brown…it’s most noticeable in the summer…probably due to too much exposure to the sun. The mom did ask the vet about it and she said it was the sun. It’s call “rusting” and I even posted some pictures of my brownish furs awhile back. ~Ernie
Emily, This was an excellent post filled with great information. I had never heard of these reasons for the coat changing except for the relationship to “sunbathing.” I am so happy to have this additional information. Astrid is blowing kisses at Sampy and sending him all her love. Love and hugs to everyone else as well. XOCK, Lily Olivia, Mauricio, Misty May, Giulietta, Fiona, Astrid, Lisbeth and Calista Jo
Very interesting! I have noticed some black cats loosing their color before. I knew that it had to do with melanin levels, but not what causes those levels to change.
Inneresting. I knew about the sun changing the coat color but not the other stuff.
If you’re one of those rare individuals who are lucky enough to have a Bombay turning brown may just be due to genetics. Bombay’s are a cross between a black American Shorthair and a sable Burmese. Sable is a deep chocolate brown color and sometimes Bombay are born this color or may turn this color after being almost completely black. It’s Perfectly Normal it just depends on which genes are dominant. Hope this helps.
I enjoyed this piece. Want to add 2 more points:
1. The only possible reason behind a cat having a black coat is that both of its parents contain black coat genes called Allele. There are various hues in the black gene which reveal cinnamon, brown, and solid black colors. If you see some brown stripes on your cat in sunlight then it means one of its parents isn’t fully black.
2. If over time your cat’s hair is looking a lot brownish than black then it means your cat is a tabby in disguise and not fully black. It happens because the tabby gene is dominant.