What is a fever coat?
Also known as stress coat, fever coat is an uncommon phenomenon where one or more kittens are born with a smokey grey coat. Fever coat is thought to occur when the mother develops a fever during pregnancy, and the unborn kittens(s) are exposed to an elevated body temperature in utero. Stress and certain medications have also been implicated as a cause.
Though these are the theorized causes of this coat appearance in kittens, there is no definitive proof of the cause. All of what has been written about is purely anecdotal, and there appears to be no research on fever coat, presumably because it would be too difficult and unethical to try to recreate.
Kitten fever cats: what do they look like?
Affected kittens are born with dark roots and a lighter silver/grey towards the tip. This differs from a smoke cat, who is pale at the roots and dark at the tips. Aside from an unusual coat, a fever coat does not harm the kitten, and when he or she molts, the adult coat transitions to its normal color.
Fever coat can develop in kittens of any color or pattern. In solids, it is an all-over silver-grey, often with darker fur on the face, ears, and lower legs, while only the black stripes are affected in tabby cats.
Fever coat cats: are they healthy?
If your kitten has a coat color abnormality, there is no reason to assume they are unhealthy. Though some causes of fever in the mother may be passed to the kitten, most kittens with fever coats are completely healthy. It is recommended to have them seen by a veterinarian and tested for feline immunodeficiency virus and feline leukemia.
What causes fever coats in cats?
Fever coat in cats may be the result of maternal fever during pregnancy which causes incomplete deposits of pigmentation. Extreme stress and medication have also been implicated; however, there is no mention of the type of medications involved. Did the cat require medications to treat an infection or disease that caused an elevated temperature? Some medications can cause a drug-induced fever.
One source claims fever coats occur in the offspring of queens with a high fever because the cat’s coat is heat sensitive. This is only true for cats who carry the heat-sensitive Himalayan gene (pointed cats such as the Siamese, Birman, Tonkinese, etc.), which is a form of partial albinism. The Himalayan gene inhibits the development of pigmentation in areas of the body warmer than 100 – 102 F (37.7 – 38.8). This gene is recessive to the full-color C gene, which means the cat needs two copies (cc) for the pointed pattern to show up. One breeder has speculated that fever coat may occur in some cats who carry one copy of the Himalayan gene (Cc). So the cat doesn’t show the pointed pattern but carries one copy of the gene. It is interesting to note that black cats with fever coats have darker points on the face and legs.
Another Ragdoll breeder in the same Messybeast article writes that her black and white kitten had a slight fever coat as a neonate, which increased after his second vaccination. There was no follow-up to see if his coat returned to normal.
Does fever coat occur in other animals?
It seems the only other species that can develop fever coats are rabbits and dogs, where the same phenomenon occurs. If the doe (female rabbit) or bitch (female dog) develops a fever during pregnancy, the offspring may be born with silver coats, which change after the first shedding cycle.
Other causes of coat color changes
Fever coat isn’t the only cause of coat color changes in cats.
Vitiligo is almost the reverse of a fever coat. The cat starts out black, and patches of white fur gradually develop, increasing over time, giving the cat a mottled appearance. The condition occurs when melanocyte (pigment-producing) cells are destroyed by the immune system or die.
Black coat turning red
The coat of some cats can develop a reddish-brown hue known as rusting that is caused by diets deficient in tyrosine, an amino acid necessary for melanin production.
Before and after fever coat in cats
Here is one example of a kitten with a fever coat:
Here is what the cat’s coat looked like as an adult:
Do any cat breeds have a similar coat to the fever coat in kittens?
The Lykoi has a roan coat, which has a similar appearance to the fever coat. Roan is only recognized in the Lykoi and no other breeds.
Black smoke vs. fever coat
A smoke coat will appear as the opposite of a fever coat. Black smoke coats contain hairs that are light-colored at the root and black at the tips/ends. The fever coat is the opposite and has dark-colored roots with lighter tips.
Does fever coat have any negative side effects?
The presence of a fever coat on a kitten does not signal that anything is wrong with the individual. We are unsure of the exact cause, and most kittens with this coat pattern are completely healthy. However, since one cause may be a maternal fever, it is a good idea to have the kitten checked out and tested for infectious disease by their veterinarian.
Frequently Asked Questions
Does fever coat go away?
Yes, when the kitten sheds their initial kitten coat, and the new mature coat comes in, the color pattern will disappear.
How common is fever coat?
Fever coat is fairly rare. Many kittens born to queens that had a fever during their pregnancy are completely normal and do not have a fever coat.
How long does fever coat last?
If a kitten has the markings of a fever coat, it will typically lose those hairs and grow a new, normal hair coat as they become an adult. This should occur between six and nine months of age if they are healthy and have adequate nutrition.
With special thanks to our feature cat Loki who was the inspiration for this article. Loki’s human kindly gave me permission to use his image, and we hope to update you with additional photos of Loki as he grows up and his coat changes.