cat's fur changing from grey to brown
Questions About Cats

Why is My Cat’s Fur Changing Color?

Sudden cat fur discoloration can be really concerning. You will be used to your cat’s coat looking a particular shade. If it begins to undergo a variation in color, you may assume that something is wrong. However, it is usually a completely natural process. If there is an issue, it can often be rectified.

Some cats change color based on the temperature. The cooler the cat it 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 tyrosine deficiency in the diet. Sudden color changes suggest hormonal imbalances, possibly caused by ill-health.

Never immediately assume the worst if your cat’s fur is changing color. Familiarize yourself with the many and varied explanations for this occurrence. If you need to, take action. If it’s part of the natural aging process, relax and let nature run its course.

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 often darken with time, while senior cats develop flecks of gray.

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

Before worrying about your cat’s changing fur color, observe it’s general and physical health. 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 a mother experiencing stress or respiratory illness while pregnant. If this occurs, a litter will be born with unique pattern markings.

The kittens may have unusual combinations of shades on their 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 so, 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 fur changes.

black cat fur turning white

Exposure to Sunlight

Dark-haired humans find that the sun bleaches and lightens their hair. The same applies to cats. If your cat is a sun-worshipper, it’s fur will change shade with prolonged 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, though. It also protects a cat’s delicate skin from being burned by the sun. Unfortunately, UV rays destroy melanin. Eventually, your cat’s its fur will also lighten in shade. Sunburn becomes likelier at this point.

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

A cat’s fur lightening in the sun is not, in itself, a significant concern. Just be aware of the implications of this. It suggests that your cat is spending a lot of time basking in UV rays. For your cat’s own safety, it is advisable to keep it indoors for a while.

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 make to thrive, though. As per 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, tyrosine deficiency explains the change in color.

This means that tyrosine must feature in your cat’s diet. Any reputable, well-balanced cat food will contain this amino acid. Meals designed especially for senior cats will place particular emphasis on appropriate balance.

Thankfully, increasing tyrosine intake will reverse the process. If changing food does not help, purchase a tyrosine supplement from a pet store. Your cat will quickly recover its traditional fur coloring.


Vitiligo is a condition that causes 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 arise.

Vitiligo comes in two forms. Focal vitiligo will be concentrated to one part of your cat’s skin. This could be the nose leather, for example. As cat’s have little hair in this area, 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 months and years.

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


If your cat has recently undergone surgery, it’s fur will likely have been shaved. This will grant a vet better access to an area that requires attention. In the aftermath of this, you may notice a change in fur color.

There are two explanations for this, neither of which are worrying. The first is that 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.

In addition, it is possible that your cat is regrowing hair ahead of a shedding cycle. This will be a different shade to that which will grow during the fall. Again, just be patient. The remainder of your cat’s new coat will eventually 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 their skin coloring. As the cat’s body temperature lowers, its skin darkens. Lighter fur will then appear 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 shade 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. To fully understand this, assess the color of your cat’s fur – before and after the change. This will help you pinpoint a reason for the shift in shade of feline fur.

Fur Color Changes and What They Mean

Note what color your cat’s fur, “should” be, compared to the variation in hue. In doing so, you will often pinpoint the explanation. This, in turn, will help you manage the situation at home.

Fur Turning Gray in Cats

Is your black cat turning white? If your cat is older than 10, this is natural. Just like humans, cats start to go 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 cats than their lighter counterparts.

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 that any life stage. Just focus on keeping your cat happy and healthy. Gray fur can suggest that other ailments are incoming, such as arthritis.

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, watch 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 effects senior cats, but it can take hold from the age of 7.

It is also possible that your cat is simply experiencing some light sun bleaching. Check how much time your cat spends under UV rays. If your cat stops sunbathing and its fur returns to black, you have a clear answer.

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

Refer back to our previous discussions to assess how to manage this. If your cat is just growing older, there is nothing you can do. If it is being bleached by the sun, watch out. 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. Just do not provide excessive amounts of this amino acid. Too much is just as dangerous as not enough.

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 cat health.

This change can also be a result of 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 with protein-rich treats.

To strike the perfect balance, offer your cat a diet of high-quality, senior-specific wet food. Unless your cat has a health concern, this will meet all dietary needs.

Light Fur Turning Brown in Cats

Lighter-colored adult cats rarely become darker with any permanence. This is especially unlikely to related 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 between 100-102 degrees Fahrenheit, the cat is fine. It will experience these changes throughout the seasons.

It’s possible that your cat has simply stained its fur, especially if it roams outdoors. Your cat’s fur could also be stained with fences from the litter tray. Clean the fur if so. This is not just unsanitary. It will also cause your cat distress, as felines prefer to keep clean.

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. No illness or explanation can change this.

If you feel that your cat’s pattern has changed, look closer. It is likely that the altered fur pigmentation is tricking the human eye. The pattern will remain in place. You may just need to work harder to see it.

My Cat’s Fur Changed Color Suddenly

A change to in color of a cat’s fur is usually a steady process. If your cat’s fur gradually changes shade, review the explanations above. In almost every case, you will find an explanation. You can then decide if further action is required on your part.

If your cat’s fur has changed color seemingly overnight, there may be a medical explanation. The ailments below are related to hormonal imbalances. This will require professional attention. 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. Differing demeanor suggests ill health.

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. At the time of writing, it has never been proved that this also applies to cats. Science suggests this is a realistic possibility, though.

Premature graying hair is linked to heightened levels of the hormone noradrenaline, aka norepinephrine. Noradrenaline is constantly released by a cat’s body in small doses. This is perfectly 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. Equally, it is not the only – or even the most reliable – symptom. 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

If your cat displays signs of stress or pain, action will need to be taken. Changing fur color should not be the overriding factor. All the same, if your cat is also graying, escalate the priority of a medical assessment.

cat's fur changing from black to brown


Hypothyroidism is the result of an underactive thyroid gland. This gland releases two hormones; triiodothyronine (T3) and thyroxine (T4). Both of 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 your cat’s fur. Fur 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 the lost hormones and restore balance to your cat’s body.


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

Jaundice is harder to spot in dark-furred cats. Pay attention to your cat’s eyes. If these 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 in and of itself. Rather, it is a side-effect of a different health concern. This will need to be identified through further tests. Your cat can then be provided with the treatment it needs.

Cushing’s Disease (Hyperadrenocorticism)

Cushing’s disease is a rare condition in cats. A cat with this concern 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, though.

Cushing’s disease is a serious issue. It will invariably be fatal if left untreated. It is important that you recognize the symptoms of the disease. These include: 

  • 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 in your cat, an MRI will be required.

If your cat is to conquer 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. Watch your cat and its habits closely. In doing so, you will find an explanation for the adjustment in pigmentation. If you remain concerned, seek veterinary advice. However, in most instances, this is a natural phenomenon.