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

Why is My Cat’s Fur Changing Color?

A cat’s fur color is a significant part of her identity. So, when the color starts to change, this can be a real shock to her owners. Black cats, in particular, experience fur fading to shades of red and brown.

Color changes on cats with dark fur are usually due to the sun’s bleaching effect. If your pet roams outdoors, you’ll see a temporary change of color shades during the summer months. However, your cat could be sick. A hormonal imbalance or disease (hypothyroidism, jaundice, Cushing’s disease, etc) can cause her fur to change shade.

If your cat doesn’t show other signs of sickness, color changes are nothing to worry about. We will explore the reasons for a cat’s fur changing shade, and if anything needs to be done about it.

Fur Color Changes and What They Mean

Feline fur can experience various color changes. It’s rare for a cat’s coat to remain one color throughout her life.

Any Color Fur Turning Gray in Cats

Older cats begin sprouting gray hairs. This usually begins around the muzzle, but can spread. Gray hair will be much more noticeable on a cat with dark fur. If your pet is white, this sign of aging will be difficult to spot. A cat with black fur will find it tougher to disguise her gray.

There is no hard-and-fast rule about when gray hairs will appear on your cat. It could be any time from age seven onward. By the time your pet reaches 11 years old, she’ll be of senior status.

This will also usually be accompanied by a change in texture to your cat’s fur. What was once a thick and lustrous coat may now appear thin and brittle. You may even find that fur falls out whenever you stroke your cat. This is a natural part of the feline aging process.

A kitten or young adult cat can turn gray due to stress. If your cat appears to be losing pigmentation in her fur too soon, consider her lifestyle. Your cat may be undergoing inner turmoil. There is also a chance that poor nutrition is responsible for her premature graying.

Black Fur Turning Brown in Cats

Black fur that turns brown is almost as common as cats fur turning gray. This is due to the sun bleaching your cat’s fur. Even the deepest black coat can start to fade during the height of summer.

It will happen faster if your cat spends a lot of time outside in the summer sun. She’ll constantly feel the sun on her back, and cats love the sun. That doesn’t mean that indoor cats will never be affected. If your cat enjoys lying by windows and soaking up rays, her fur will likely fade.

This is a temporary change. Cats shed and grow their fur according to the temperature outside. That’s a basic survival mechanism. As summer turns to fall, you should start noticing your pet’s fur darkening again. The brown fur is being covered by new, dark fur that is thickening your pet’s coat.

can cats fur pattern change?

If your black cat remains closer to brown all through the winter, it may just be a natural part of the aging process. Some cats turn a shade of brown before they reach gray.

Unfortunately, organ failure is also a possibility. As older cats experience issues with their liver, kidneys, and thyroid, their fur loses luster. Keep an eye out for any of these symptoms:

  • Excessive urination
  • Vomiting and diarrhea
  • Ulcers in and around the mouth
  • Foul-smelling breath
  • Sudden and inexplicable weight loss
  • General lethargy, spiked by occasional hyperactive moments
  • Changes in temperament

Cats will naturally hide any sign of illness. Her fur changing color could be the first warning sign. If your cat displays no other signs of ill health, sunlight is likely bleaching her fur.

Black Fur Turning Red in Cats

As dark, black fur fades to a coppery red, it may be sun exposure or a problem with your cat’s diet. Your cat may not be producing enough melanin to maintain her black coat without proper nutrition.

The most common example of this is tyrosine deficiency. Tyrosine is one of the amino acids that your cat requires to function properly. The pigmentation of your cat’s fur comes from this non-essential amino acid, which is created organically.

However, your pet needs to consume tyrosine to create melanin. If your cat’s diet lacks protein, she will lack melanin. This is what fades her coat from black to red. The same can also occur through zinc or copper deficiency. Ensure that your pet is eating food that’s rich in protein.

Brown Fur Turning Black in Cats

Just as a tyrosine deficiency turns fur from black to red, excessive tyrosine turns brown fur black. If your cat’s fur is darkening, review her diet. If your cat is eating too much protein, you may need to reduce her intake. You can also review the treats that you feed to your cat.

Light Fur Turning Brown in Cats

If you have a light-colored cat, you may find her fur turning darker. This is rarely a result of tyrosine. A feline must have some dark fur in order to experience this color change. Instead, a white or light gray fur turning brown is usually staining of some kind.

This could be urine or fecal staining. If a cat’s fur is also greasy or clumpy, then she cannot groom herself. This means that she’s not removing these stains herself.

Perhaps your cat is staining her fur through excessive grooming. Feline tongues contain bacteria, and this can cause staining. A cat grooming herself is natural. If your cat is licking her own fur without pause, it’s not healthy. Your cat may be stressed, or hiding a sickness of injury.

Medical Reasons for Cat Fur to Change Color

In addition to dietary issues, there could be a medical explanation for your cat’s color change. Some common examples of these, as per PetCoach, include:

  • Cushing’s disease
  • Hypothyroidism
  • Jaundice
  • Skin cancer

Let’s take a look at each of these ailments, discussing the symptoms and treatment.

Cushing’s Disease

Cushing’s disease is a condition that attacks the adrenal glands. A cat with this ailment will create an excess of the hormone cortisol in her body. This can have serious long-term consequences, including death. The symptoms of Cushing’s disease include:

  • Excessive thirst, leading to frequent urination
  • Bloating around the abdomen
  • Damage to the skin (this symptom often goes hand-in-hand with changing fur color).
  • Panting and difficulty breathing
  • Constant hunger and overeating, leading to weight gain
  • Muscle weakness and lethargy

Cushing’s disease is usually the result of a tumor on the pituitary gland. This is found on the base of the brain. This means that scans will be necessary to diagnose a problem.

If your cat has Cushing’s disease, the tumor will be removed if safe. This can be tricky due to the location of the tumor. Your cat may also need to undergo chemotherapy or radiotherapy.


Hypothyroidism sees cat fur change color, and even fall out in clumps. This ailment relates to an underactive thyroid gland. But it’s comparatively rare in cats.

If your cat has an underactive thyroid, she’ll be very lethargic. This lack of energy will affect her fur, which will become listless. Her fur will grow dull in color, appear unkempt, and start to fall out. Your pet will likely gain weight without her food allowance changing.

Once diagnosed, hypothyroidism can quickly be reversed. Medication will be administered. If your cat is gaining weight and seems very sleepy, take her to a vet.

cat's fur changing from black to brown


Jaundice, as Manhattan Cats explains, is a disease of the liver. Jaundice turns a cat’s skin a shade of yellow. This will change the color of light fur. White or gray fur will start to take on a yellow tinge.

If you think your cat’s fur looks odd, check her stomach. The skin here will tell you everything you need to know. Jaundice is often a symptom of a more serious health concern in cats. Get your cat to a vet for a formal diagnosis and treatment.

Skin Cancer

Tumors on your cat’s skin can be benign or malignant. A malignant tumor will often lead to skin cancer, aka Bowen’s disease, and must be removed.

Tumors are all but invisible to the naked eye. Fur changing color is not, however. A vet will need to run x-rays, ultrasounds, and other tests to diagnose skin cancer in cats.

Should he discover a tumor, he’ll decide on the next course of action. This will be sped up if he suspects Bowen’s disease. This condition manifests as a series of sores on your pet’s skin.

A benign tumor will usually be removed surgically. Although the tumor is comparatively harmless, that may not always be the case. This surgery prevents the risk of the tumor from turning malignant.

A malignant tumor will also be surgically removed. Radiotherapy or chemotherapy will likely be required. This is why it’s essential that your cat doesn’t spend too much time in the sun. Prolonged sun exposure is a common cause of skin cancer.

My Cat Changes Color Many Times Each Season

Is your cat an oriental breed? If this is the case, regular color changes will naturally occur. Oriental cats manage the color of their fur based upon the temperature of their skin.

As Pet Health Network explains, the warmer a cat’s skin, the lighter her fur becomes. Such cats could have light fur on their body and darker markings around their face or tail.

If your pet displays any signs of distress or ill health, get them examined. In the case of oriental cats, these regular changes are to be expected.

My Cat Has Different Color Fur After an Operation

It’s common cats to develop a different shade of fur after they have been spayed. This is nothing to do with hormonal changes, but a matter of logistics. The fur on your cat’s belly will likely need to be shaved to make the procedure possible.

Here’s where the color change comes in. This shaved fur will grow back. However, the fur of a cat is like the hair of a human child. It does not stay the same color permanently.

Spaying a kitten may result in two shades of fur growing at once. The fur on top of your cat’s body will steadily transition into its final color. That which regrows after being shaved moves ahead of schedule to your cat’s final color.

The same will happen if your cat gets herself into a scrape when young. If fur is removed for any reason, it will grow back. This applies to a cat that has her fur snipped with scissors, shaved, or any surgical procedure. This fur will be replaced, but it may not immediately match the existing shade.