Fever Coat -What Is It and Why Do Foxes Get It?

  That, is a good question and I hope this gives the Reader some idea.

Dakin Humane Society from 3rd June 2022  https://www.dakinhumane.org/blog-full/what-is-fever-coat#:~:text=Even%20though%20their%20coat%20pigment,a%20year%20in%20some%20cases.

What is Fever Coat?

"In April, we shared a photo on social media of a group of kittens who had been receiving medical care at Dakin. Very quickly, the post soared in popularity and we received dozens of inquiries about a particular kitten with a very distinctive coat pattern.

"That kitten’s name is Verdell and while he has many special qualities, the salt & pepper pigment to his coat was a temporary anomaly.

"Verdell displayed what’s known as fever coat (or stress coat). This fairly uncommon phenomenon occurs when an adult cat experiences an illness or severe stress that causes a spike in body temperature during pregnancy.

"During feline gestation, the developing fetus goes through many changes as they grow. Prior to birth, the pigmentation of a kitten’s coat is very sensitive to heat. If a mom cat experiences a fever due to illness or prolonged stress, it has the potential to affect the developing pigment of her kittens’ fur.

"Fever coat typically presents as silver, grey, or cream-colored coats, most prominent at the tips of the fur, darkening toward the root.

"Fever coat creates a visually striking coat but has no negative implications for the kitten’s overall health going forward. Even though their coat pigment did not fully develop in the womb, their coat color is still written in their DNA and will present a little later in the kitten’s life. Fever coat typically resolves around four months of age but can take up to a year in some cases."

You may hear of a "fever coat" fox and online you will find this explanation:

https://www.facebook.com/blackfoxesuk

"Fever Coat in Foxes

There are several different circumstances that may occur where a fox's coat colour may change. This can be down to a variety of different reasons including stress, illness or even environmental factors.

"Extreme stress or infection in a pregnant vixen can result in fever, which in turn can disrupt the distribution of temperature-sensitive pigment cells during neural crest development of the young. The condition is known as #FeverCoat and is also seen in kittens.

"It can effect the whole litter to varying degrees and makes the young appear paler or even white at first, but as they age they will begin to darken and by the time they reach their first full moult at aged two, they will generally have developed their full colouration."

The above fox is one of several white foxes from a leash wiped out in the 1930s. It looks to be around 2+ years old and the other from this leash we have images of also looks adult so this was not albinism but a colour variation of red foxes.  White foxes were not "extremely rare" and there are accounts of them being hunted and killed and there are a lot of taxidermy examples which shows how un-rare they were.

It needs to be noted that vixens do suffer verminous pneumonia (lung worm) and other illnesses so if this affects fox cubs we might expect more fever coat cubs. To date I do not have many images of fever coat foxes but I do have a few white foxes in the data base.