why does my black cat look brown in the sun?
Questions About Cats

Why Is My Cat’s Fur Changing Color?

Sudden cat fur discoloration can really catch your attention. You will be used to your cat’s coat looking a particular shade. So, if it begins to undergo a variation in color, you may be concerned that something is wrong.

Some cats change color based on the temperature. The cooler the cat is, the darker its fur grows. Cats also change color as they age. Young cats grow darker, and older cats turn gray. UV rays from the sun bleach dark fur, as does a tyrosine deficiency in the diet. Sudden color changes suggest a hormonal imbalance.

Don’t assume that sickness is the reason why your cat’s fur is changing color. Familiarize yourself with the varied explanations.

Why is My Cat’s Fur Changing Color?

Consider whether your cat’s fur is organically changing shade with age. Cats do not always keep the hair color they are born with. Light-colored kittens may darken with time, while senior cats will develop flecks of gray.

Aside from nature, there could be another explanation for your cat’s fur changing color. Whether this is a concern depends on a range of factors. These include the age and breed of your cat and its demeanor.

If there is a medical problem, other symptoms will present themselves. If not, the process will be entirely natural.

Fever Coat

Fever coat is a condition that impacts kittens. It is caused by the mother experiencing stress or respiratory illness while pregnant. If this occurs, the litter will be born with unique pattern markings.

The kittens may have unusual combinations of shades of fur. Alternatively, they may have a block color rarely associated with their breed. Oftentimes, this will be silver or cream. This will be notable in breeds like the Siamese, who are usually born with white fur.

Fever coat is not harmful to the kitten and does not last long. After a few weeks, the coat reaches its natural shade. From this point, it should not change further. If it does, there will be another explanation.

For the avoidance of doubt, fever coat only applies to newborn kittens. An adult or senior cat cannot develop late-onset fever coat. If a cat is aged several months or older, fever coat will not explain its fur changes.

cat fur discoloration

Exposure to Sunlight

Dark-haired humans find that the sun bleaches and lightens their hair. If your cat is a sun-worshipper, its fur will change shade due to prolonged sun exposure. This is most noticeable in black cats, who will turn a rusty color.

This is due to melanin. Melanin is found organically in a cat’s body. It is a genetic inheritance from a cat’s parentage. Eumelanin provides black or dark brown fur, while pheomelanin creates red and orange shades.

Melanin is not purely aesthetic. It also protects a cat’s delicate skin from being burned by the sun. Unfortunately, UV rays destroy melanin. Eventually, your cat’s fur shade will lighten.

A cat’s body is constantly replacing melanin. This means that, in time, its fur will return to its previous shade. Usually, it must undergo a shedding cycle for this to happen.

A cat’s fur lightening in the sun is not, in itself, a concern. However, it suggests that your cat is spending too much time basking in UV rays.

Tyrosine Deficiency

A dark cat that steadily turns lighter may be experiencing a nutritional deficiency. Usually, this relates to tyrosine. Tyrosine is considered a non-essential amino acid as it is created within the feline body.

Cats need twice as much tyrosine as their bodies can produce. According to the Journal of Small Animal Practice, the average cat needs over 5g of tyrosine daily.

Tyrosine is related to the production of melanin. A lack of this ingredient will bleach a cat’s fur. If your cat does not spend time in the sun, a tyrosine deficiency will likely explain the color change.

Tyrosine must feature in your cat’s diet. Any reputable, well-balanced cat food will contain this amino acid. Meals for senior cats will place particular emphasis on providing the appropriate balance.

Thankfully, increasing the tyrosine intake will reverse the process. If changing food does not help, a tyrosine supplement will be beneficial.


Vitiligo is a condition that causes the skin to lose pigmentation. This will result in white spots and patches around the cat’s body. Any hair that surrounds this skin will also lose coloring. Vitiligo is rare in felines, but it can sometimes arise.

Vitiligo comes in two forms. Focal vitiligo will be concentrated on one part of your cat’s skin. This could be the nose leather, for example. As cats have little hair in this area, the fur color is unlikely to be affected.

Generalized vitiligo will cause random, cobweb-like patches throughout the skin and fur. This will be much more noticeable. Vitiligo usually starts small and spreads gradually. You will notice increasing changes to your cat’s fur color over the months and years.

As explained by Experimental Biology and Medicine, vitiligo is an autoimmune disease. There is no cure for the condition. Thankfully, vitiligo will not cause pain, and your cat will live a normal life.


If your cat has recently undergone surgery, its fur will likely have been shaved. This will give the vet better access to an area that requires medical attention. The aftermath of this is that you may notice a change in fur color.

There are two explanations. Your cat’s hormones are reacting to the operation and anesthetic. This can lead to a change in fur hue. This will be temporary. Before long, your cat will return to its normal fur color.

Also, your cat may be regrowing hair ahead of a shedding cycle. This will be a different shade to that which will grow during the fall. In time, your cat’s new coat will catch up and match.

Skin Temperature

Some cat breeds are genetically prone to fur color changes. This is common in pointed breeds. As the cat’s temperature changes, so will its skin coloring. As the cat’s body temperature lowers, its skin darkens.

Lighter fur will then appear as a deeper shade. This table summarizes cat breeds that regularly change color and the reason why it happens:

Cat BreedReason for Fur Color Change
Balinese:Skin temperature
Birman:Skin temperature
British Shorthair:Skin temperature
Chinchilla:Only outer, thicker fur is colored – different shades may appear after shedding.
Highlander:Skin temperature
Himalayan:Skin temperature
Javanese:Skin temperature
Napoleon:Skin temperature
Oriental:Skin temperature
Persian:Often born white, but transition into a wide array of colors
Peterbald:Skin temperature
Ragdoll:Skin temperature
Siamese:Born white and darkens with age; fur color fluctuates depending on skin temperature.
Siberian:Skin temperature
Tonkinese:Skin temperature

If your cat’s breed is not listed, there will be another explanation. You’ll need to assess the color of your cat’s fur before and after the change.

Fur Color Changes And What They Mean

Note what color your cat’s fur should be compared to the variation in hue. By doing so, you’ll be able to find the right explanation.

Fur Turning Gray in Cats

Is your black cat turning white? If your cat is older than 10, it is natural as cats start to gray as they age. This is because a cat’s body produces less melanin as it grows older.

Gray hairs will first appear around the muzzle. The gray fur may or may not spread from there. Gray fur is much more noticeable in darker-colored cats than their lighter-colored cats.

If your cat is turning gray over time, there is no need to worry. As long as it is not an overnight change, it’s just nature taking its course. Your cat may still be a kitten in your mind, but it is a senior citizen in feline years.

Graying fur is not a sign of imminent demise. Cats live longer as seniors than they do at any life stage. Gray fur can suggest that other ailments are likely to become a problem in the future, such as wobbly back legs.

Black Fur Turning Brown in Cats

Black fur is fading to brown is the first stage toward eventual graying. A cat’s fur is unlikely to go straight from black to white. There will be a slow and steady fading process.

If your cat seems too young to be going gray, check for other behaviors. If your cat is acting out of sorts, it may have an organ problem. Be mindful of chronic renal failure, in particular. This typically only affects senior cats, but it can sometimes take hold from the age of 7.

Check how much time your cat spends under UV rays. If your cat stops sunbathing and its fur returns to black when it’s less sunny, you have a completely harmless explanation.

Black Fur Turning Red in Cats

Black fur turning a rusty shade of red has three explanations.

  • Melanin production is slowing down with age
  • Fur has been bleached in the sun
  • Your cat has a tyrosine deficiency

If your cat is growing older, there is nothing you can do. If it is being bleached by the sun, then the cat may be experiencing excessive UV exposure and is at heightened risk of skin cancer.

A tyrosine deficiency should be managed through diet or supplementation. Do not provide excessive amounts of this amino acid.

Brown Fur Turning Black in Cats

Brown fur darkening to black is a symptom of excessive tyrosine. Ensure that your cat is getting the correct quantities of this amino acid. Striking the right balance of vitamins and minerals is critical to a cat’s health.

This change can also be due to excessive protein in the diet. As per Veterinary Clinics: Small Animal Practice, older cats still need protein. In fact, they need this more than any other food group. Just avoid overfeeding a senior cat protein-rich treats.

Light Fur Turning Brown in Cats

Lighter-colored adult cats rarely become darker with any permanence. This is unlikely to relate to a dietary issue. A cat with white or light brown fur will lack the appropriate pigmentation to darken sufficiently.

If your cat has pointed coloration, fur darkens when the ambient temperature drops. This is because the skin also darkens. Take your cat’s body temperature. If it is about 100.5-102.5 degrees Fahrenheit, the cat is fine.

Your cat may have stained its fur, especially if it roams outdoors. Your cat’s fur could even be stained with feces from the litter tray.

Can a Cat’s Fur Pattern Change?

A cat’s fur can change color, but its pattern will not alter. A spotted cat will always be spotted, and a stripy cat will always have stripes.

If your cat’s pattern has changed, the altered fur pigmentation may be deceiving the human eye. The pattern will remain in place.

My Cat’s Fur Changed Color Suddenly

A change in the color of a cat’s fur is usually a steady process. If your cat’s fur has changed color seemingly overnight, there may be a medical explanation. The ailments below are related to hormonal imbalances. Your cat will require medication and/or lifestyle changes.

Behavioral changes will accompany these concerns. Anthrozoos confirms that humans erroneously link feline behaviors to fur color. The two matters are unrelated. A cat’s personality should not change with pigmentation.

Stress and Physical Pain

Intense periods of stress can turn human hair gray. Applied Animal Behavior Science confirms that stress can also turn canine fur gray. It has never been proven that this also applies to cats. Science suggests that this is a realistic possibility, though.

Premature graying hair is linked to heightened levels of the hormone noradrenaline, aka norepinephrine. A cat’s body constantly releases noradrenaline in small doses. This is normal. It differs from adrenaline, which is scientifically known as epinephrine.

Noradrenaline is connected to the nervous system. During times of intense stress or pain, it floods the body as a reflex. As per the Journal of Physiology, this also occurs in felines. This suggests that the fur of a cat in constant pain or stress can quickly turn gray.

Graying fur is not necessarily a sign of stress or ill health, especially in older cats. Look out for these warning signs:

  • Hiding and reluctance to interact
  • Excessive verbalization
  • Uncharacteristic displays of aggression
  • Restlessness
  • Lethargy and depression
  • Lack of interest in grooming or play
do cats fur change color as they age?


Hypothyroidism is the result of an underactive thyroid gland. This gland releases two hormones; triiodothyronine (T3) and thyroxine (T4). These hormones are essential for a cat’s body and organs to function.

If the cat’s thyroid gland is underactive, it will not receive enough T3 or T4. This can lead to the following symptoms:

  • Constant lethargy and exhaustion
  • Weight gain
  • Excessive thirst
  • Low body temperature (below 100 degrees Fahrenheit)
  • Lack of grooming
  • Lack of interest in play or activity

More pertinently, a hypothyroid cat will have a dull, listless coat. The color and sheen will fade from the fur. It may even start to fall out in clumps.

Hypothyroidism is difficult to diagnose as it is rare in felines. If your cat does have the condition, it will require daily medication. This will replace any lost hormones and restore balance to your cat’s body.


Jaundice is a condition of the skin, not fur. Jaundice will see your cat’s skin take on a yellow hue. This will be noticeable in light-colored cats. The fur will start to look dirty and discolored.

Jaundice is harder to spot in dark-furred cats. If your cat’s eyes are dull and yellow, jaundice is possible. The gums may also be pale and faded. Feline jaundice is most commonly associated with liver disease. Aside from discolored skin, eyes, and gums, common symptoms include:

  • Loss of appetite
  • Sudden weight loss
  • Vomiting and diarrhea
  • Chronic dehydration
  • Blood in the urine or feces
  • Lethargy and depression

Jaundice is not a condition that can be treated. Rather, it is a side-effect of a different health concern.

Cushing’s Disease (Hyperadrenocorticism)

Cushing’s disease will generate an excessive amount of cortisol, aka the stress hormone. This ailment differs from stress caused by generalized anxiety or physical pain. The impact on fur can be similar.

Cushing’s disease will invariably be fatal if left untreated. You must recognize the symptoms of the disease: 

  • Excessive thirst and associated urination
  • Excessive hunger
  • Shortness of breath
  • Lethargy and depression
  • Bloated or distended abdomen
  • Weak, damaged skin

The cause of Cushing’s disease will be a tumor. This tumor will be located on the brain’s pituitary gland. This is found on the base of the brain. If a vet suspects Cushing’s disease, an MRI will be required.

If your cat is to recover from Cushing’s disease, the tumor must be surgically removed. Molecular and Cellular Endocrinology describes this as a safe and effective treatment. In some cases, radiotherapy or chemotherapy may also be required.

Cat fur changes color all the time. In most instances, this is a perfectly natural phenomenon, but health conditions can sometimes be responsible. If so, your cat is likely to show other physical symptoms.