Polymorphism In Red Foxes
Fur farming ended in the UK at the turn of the millennium. However, escapes and releases did occur when the industry was still here and thriving. Despite the UK ban and the global movement to ban fur farming, London remains a world center for fur buyers to this day. It is an industry that produces 15 million fox pelts a year, with up to 70% of the fur industry's production of fox fur originating from Europe alone.
Hybrids between the North American red fox and the European red fox are possible, as they are both vulpes vulpes. Though it is interesting to note that the North American red fox and the European red fox were once classified as two separate species; vulpes vulpes in Eurasia and vulpes fulva in the America's (Tesky, 1995), being considered a singular species since 1959 (based on anecdotal reports). Modern technology however, has recently provided evidence that our original assumption on species divergence may have been correct, detecting two distinct red fox lineages that were isolated from each other during the last glaciation.
Hybrids between the Red fox and the Arctic fox, have also been recorded within both wild and captive bred populations. There have been no sightings on UK shores of any such hybrids, but it is important to note that both Silver foxes and Blue foxes (the domesticated Arctic fox) were once bred here by the fur trade and both species are kept here as exotic pets today. There have been a handful of "white fox" sightings reported in the UK, which are noted to have been that of lost, captive bred Arctic foxes.
The increase of unusually coloured foxes seen in the UK fox population coincides with the keeping of foxes as exotic pets and animal ambassadors. While anomalous coat colours do occur naturally, some do not and are a product of domestication processes. Previous sightings have occurred far less frequently than they have over recent years and due to the physical appearance of some of the individuals identified in reports, it is clear that some of the sightings have not been that of native foxes.
For more information on the red fox, please visit The Fox Website and Wildlife Online. For more on silver fox colour mutations, please visit our Silver Fox Coat Colour Mutations guide, by Alyssa Newsome.
Melanism & Fox Genetics
Melanism is a recessive trait that allows for greater expression of the pigment melanin in an animals skin or coat, which gives the animal a darker colouration. Melanistic coat colouration's are a rare genetic trait in UK red foxes, as both parents must carry the recessive gene for full melanism to be expressed. In the wild, melanistic foxes would rarely get the opportunity to reproduce with other foxes of the same colour morph but in farms, silver foxes are explicitly bred with others that share the same recessive melanistic trait. This selective breeding has resulted in colour mutations that do not exist in wild populations (this includes luecistic, "white" and red forms e.g. "cherry red fox") and has altered the physiological and behavioural profile of the silver fox in comparison to it's wild cousin.
"Psysiological causes of coloration, including melanism, are evident but poorly researched. The relative importance of evolutionary forces responsible for external coloration varies greatly between vertebrate taxa, but the reasons for this variation are not yet understood"
"Overall, silver foxes account for about 10% of colour morphs. Jet black foxes are, however, very rare in Europe; in his 2005 Carnivores of the World, Ronald Nowak notes that such foxes are confined to the extreme north of Europe and make up about 1% of the population"
Inheritance of melanism in red foxes can be explained through Mendelian genetics, first proposed by Gregor Mendel is 1865;
"Prior to Mendel, most people believed inheritance was due to a blending of parental ‘essences’, much like how mixing blue and yellow paint will produce a green color. Mendel instead believed that heredity is the result of discrete units of inheritance, and every single unit (or gene) was independent in its actions in an individual’s genome."
Belyaev's farm fox experiment demonstrated how Mendel's theories were correct, disproving Lamarack's theory of inheritance of acquired characteristics and the Lysenkoism opposition which dominated at the time. Today, we consider Mendel's theories the cornerstone of modern day genetics, with Belyaev's farm fox experiment sparking the emergence of new fields of scientific research into genetics, domestication, epigenetics (how environment influences genes) and human and animal medicine.
"Belyaev knew his genetics and firmly believed that Lysenko's views were false.. working as a young man at the Central Research Laboratory of Fur Breeding in Moscow, he rashly expressed his opposition. He was fired from his job as a result... Belyaev searched for a topic that was scientifically interesting but not politically dangerous. He felt drawn to the issue of animal domestication. He chose [fur] foxes, common in Siberia... [a result of Russian explorers and the fur trade]"
"Belyayev's experiments were the result of a politically motivated demotion... Belyayev has since been vindicated in recent years by major scientific journals, and by the Soviet establishment as a pioneering figure in modern genetics"
In August 2017, to show their respect to the scientific contribution of Dmitry Belyaev, the Institute of Cytology and Genetics held a conference and erected a monument in his honour, commemorating the 100th anniversary of his birth.
Red Fox, Melanism & Mendelian Genetics: Why Are Black Foxes So Rare?
UK Fox Genetics:
While there is much research on foxes, there is very little research into the population genetics of wild red foxes in the UK. Research is now beginning to focus on this field of study and tests are being developed to help distinguish different genetic populations.
"There are no published reports on the population genetics of foxes in Britain. In this study, we aim to provide an insight into recent historical movement of foxes within Britain, as well as a current assessment of the genetic diversity and gene flow within British populations"
Initial results from the latest research demonstrates it is possible to distinguish wild foxes from captive bred foxes, as well as distinguishing between regional differences in the genetics of wild and farmed foxes. Such information will allow researchers to gain a better understanding of the genetic variation within the UK fox population.
"Analysis of the origin of domestic animals is of wide interest and has many practical applications in areas such as agriculture and evolutionary biology. Identification of an ancestor and comparison with the domesticated form allows for an analysis of genetic, physiological, morphological and behavioral effects of domestication. Because fox breeding has been an ongoing process for over a century, differences are expected between farm and wild populations at the chromosomal level"
"For each of the genes investigated specific SNP profiles characteristic only for farm foxes and only for wild foxes were noted. At the same time, specific SNP profiles were noted for wild foxes from North America and from Europe"
Farm Foxes & The Silver Rush
The farm fox or "silver fox" is the domesticated version of the melanistic North American red fox. It is a selectively bred farm animal that exists as a result of "the silver rush", which is thought to have started on Prince Edward Island around 150 years ago. Fox farming began as an alternative to the historic practice of hunting and trapping foxes, being promoted as a means to improve pelt production and quality.
Over the years, as a direct result of selectively breeding foxes for coat colour and quality, new coat colours began to appear. These novel colour mutations were difficult to produce and did not exist in wild populations naturally, resulting in the increased popularity of fox fur as a luxury item and the huge price unique pelts would sell for at the time. Back then, a breeding pair of platinum foxes would cost the equivalent of £1 million. Today, such a pair of foxes can be obtained from breeders for under £1000.
The commercial selective breeding of melanistic foxes in captivity by man for the fur trade pre-dates our production of inbred laboratory strains of rodents (early 1900's). In fact, it was the fox farming community that provided the need for formulated and pelleted diets, the development of which then allowed the scientific community to improve the welfare and longevity of laboratory rodents. Fox farmers even contributed to veterinary and animal science directly by adding to our knowledge of genetics and through the development of the first distemper vaccine, which our pets use modern versions of today.
The silver fox's status as a domesticated farm animal is not fully recognised (only the experimental foxes are considered officially domesticated), though it is acknowledged in Canadian and EU literature that farm foxes are to be treated as "domesticated farm animals" under farming regulations.
While farm foxes have been historically bred for unique colour traits and not for temperament, modern fur farming accepts that foxes which can tolerate human handling have higher welfare standards. As a result, fox farmers in Europe are now required to breed for improved temperament and reduced fear of man.
As a result of their domestication, silver foxes display a much greater variety of polymorphism than what is seen in wild red foxes in the UK;
- silver foxes are slightly larger, with longer hind-limbs,
- have larger, fuller tails and longer white tail tips (some also display a spiral pattern),
- have shorter, broader faces,
- as well as thicker, longer coats, with a much wider variety of colouration's.
Below is an example of the Georgian Red colour morph. The Georgian colour morph is considered the Russian version of the marbled silver fox, it is a rare colour morph that is a direct product of intensive selective breeding for unique colour traits.
"The Georgian [fox], also called the snow mutant, was first documented in Russia in 1943. It is a white fox with black spots on the face, back and feet... These foxes are often described as 'freckled'. The gene is incompletely dominant, and is lethal in homozygous condition... These foxes were heavily restricted when they were first discovered during the period of the USSR, and for a time only existed in Russia. They now are present across Europe, but they are not in the North American [or UK] pet trade at this time, except for Russian domesticated foxes imported to the US"
Historical records show that the earliest reports of fox farming in the UK can be dated back to the 1800's;
"A more unusual trade to be recorded by the archaeological record is that of silver fox farming. A brick tower (NHER 8023) that stands south of Heath Farm on the Short-Thorn Road supposedly belonged to a post medieval silver fox farm, with the farmer sitting in the tower to watch the foxes"
However, the Silver Rush and commercial fox farming wasn't to hit the UK until the early 1900's;
"Seven 'Silver Foxes' are recorded as having been born in the Gardens 1857-1862, and also five hybrids between this species and the European Fox, two in 1832, three in 1870. The farming of foxes for the fur industry started in the British Isles in 1920 and by 1932 there were 115 breeders across the country"
"When the demand for fox furs peaked in the 1930's many turned to breeding the coveted varieties, particularly silver, blue, platinum and white (Arctic) fox. Some 150 silver fox fur breeders were listed in the British Fur Trade Yearbook for 1933"
Fur farming wasn't the only commercial use of foxes in the UK in the early 1900's. English rat catcher John Wheeldon, trained foxes for "economic use" by teaching them to assist him and his dogs with providing rat catching services (a practice adopted by the Chinese in 2004 with silver foxes, in order to keep mole rat plagues under control).
"John Wheeldon, better known as John Gaunt. He lived at Sawmills but worked for the Midland Railway Company, travelling the lines as a rat catcher. He is the only person known to have successfully trained foxes to 'rat' for economic use, and claimed they were better than terriers because they could hold five rats in their mouths at once.
The rat catcher had to be quick because, unlike a terrier, foxes did not kill the rats outright. His best two foxes however, were killed accidentally by gamekeepers. Such was his national fame that he was described in a book as a 'great sportsman great Englishman"
Today, the attitude to wearing fur in the UK is very different from what it once was, with fur farming being banned under the Fur Farming (Prohibition) Act 2000 - prohibiting the keeping of animals solely or primarily for the value of their fur.
There were 11 fur farms left in the UK just prior to the ban, most of which had ceased breeding foxes many years earlier. Historic UK fox farms included Hollywood Silver Fox Farm in Lincolnshire (who's tort law case demonstrates how anti fox farming views have existed since the practice began), Mytholm Fur Farm in Halifax (the release of farm foxes in this area at the start of WWII is believed to be the reason why melanistic traits are greater in foxes in and around Halifax today), Lumphanan Silver Fox Farm in Aberdeenshire and Sheringham Zoo and Silver Fox Farm in Norfolk.
Photo and video evidence also documents fox farms in Kent, Warwickshire, Sussex, Hertfordshire, Yorkshire and East Lothian. Other towns with online evidence of historical fox farms include Yateley, Norwich, Headley, Mulbarton, Walsall and Cowlinge. With silver foxes being "bred in Bearfoot wood in the 1930's" according to British History Online. A possible reference to the farm situated at Broadoak, Gloucestershire.
"I was 20 years old in 1932... I only worked on the farm for a few months during the summer of that year... A driveway along side of the bungalow led down to the Fox Kitchen and the Offices, the kitchen was used for the fox's food, which as far as I can remember consisted of a lot of eggs and baby turkeys, there were a lot them about, and I do remember that the kitchen was spotlessly clean...
The foxes themselves were housed in pens completely made up of chicken wire both round the sides and on the floor, presumably to stop them digging their way out. They were beautiful creatures with black and silver fur. I supposed they were bred for their fur. There must have been just under a hundred as far as I can remember"
In 2000, as a tribute to their historical involvement in the once thriving trade of UK fur production, the Shetland Museum opened an exhibition dedicated to the history of fox and mink farming on the isles, documenting their involvement in the fur trade, as well as the humane farming practices the isles brought to the industry. Since it's peak in the mid-1900's, the fur industry has considerably reduced housing standards compared to what was once considered acceptable, with the original fur farmers keeping their foxes in a similar way to how zoo's and private keepers might today.
It is also interesting to note, that the fur trade began not only as a means to improve and control pelt quality and colour, but it was also hoped to reduce the burden that hunting for fur was placing on wild populations. Given man's attitude towards hunting at the time, combined with the increasing demand for fox fur, it seems possible the North American red fox may have ended up hunted into extinction, had farming not have been able to meet the demand. As it stands, pure native lines of North American red fox are considered a threatened species today. The result of historic practices of hunting and trapping, hybridisation with introduced foxes (both farm foxes and European fox), current human activity and increasing environmental pressures.
The Domesticated Silver Fox
Throughout the experiment, foxes were temperament tested and given a tameness classification level, being graded from 1st-3rd Class based on their results to the testing. Only the top 20% of each generation from the 1st Class group were allowed to became the next seasons breeding stock. Within 10 generations, they were producing foxes that were tame beyond what they had expected from even a Class 1 animal and an Elite Class (known as the "Domesticated Elite") had to be created, with 18% of foxes making the grade. By 2009, 70-80% of foxes were being graded as "Domesticated Elite".
The experiment showed that the foxes are fundamentally different in genetics and behavior compared to their wild counterparts, having a greater ability to cope with stress. A trait that is believed to be the result of a change in the production of stress hormones;
"It is not the case that coat color causes a difference in temperament, but rather that certain physiological processes underlie facets of both coat color and behavior. In particular, the hormones and neurotransmitters involved in the stress response and other behaviors are closely integrated with pigment production. For example, the neurotransmitter dopamine and the hormones noradrenaline and adrenaline, which are involved in the stress response, have the same biochemical precursor as the melanin pigments (Anonymous 1971, Ferry and Zimmerman 1964).
In addition, dopamine directly influences pigment production by binding to the pigment-producing cells (Burchill et al. 1986). Dopamine indirectly influences pigment production by inhibiting pituitary melanotropin, also known as melanocyte stimulating hormone (MSH), which is responsible for stimulating pigment cells to produce pigment (Tilders and Smelik 1978)"
Given that the parent population of experimental foxes were obtained from North American fur farms and that there are only forty genes found to differ between domesticated and non-domesticated farm-raised foxes (with 2,700 genes difference between the wild foxes and either set of farm-raised foxes), it makes sense that all sliver foxes display phenotypes and behavioural traits not seen in wild foxes, despite the different forms of domestication. However, there are further differences between those foxes scientifically domesticated for tameness and their fur farm counterparts;
- Tame, dog-like behaviours (whining for attention, licking, tail-wagging, playfulness, and barking),
- shorter legs, shorter and curled tails* and spotted fur,
- narrower skulls and shorter snouts than that of wild foxes,
- females began to come into heat twice a year instead of just once as in the case of wild foxes, also,
- tame fox cubs opened their eyes sooner and developed a fear response later than wild fox cubs.
*Curled tails (as well as "floppy ears"), while once thought to be the result of domestication processes, was eventually considered an unwanted mutation that had been inadvertently selected for in the process of domestication. As a result, it is not a trait seen in the experimental fox population today.
The foxes in this experiment have been selectively bred for over 60 generations for their calm temperament and ability to tolerate man. They are considered scientifically "domesticated pets" as a result of the process that has occurred; unlike that of farmed silver foxes, which have not undergone the same process.
Lyudmila Trut and fox scientist Anna Kukekova continue the legacy after Dmitry Belyaev's death in 1985. The foxes continue to be bred at the Institute of Cytology and Genetics for scientists to better understand the process of domestication, but they are now also sold (neutered) to vetted clients (at the cost of several thousand pounds), as a means to fund the continuation of the experiment after it hit financial hardship. In taking such measures, they have been able to continue this valuable and long-standing research project.
Siberian fox scientist Irina Mukhamedshina trained her domesticated fox Anna (above), after obtaining her from the Institute of Cytology and Genetics as a pet of her own. Anna was as obedient as any dog and was able to master some amazing skills in her time with Irina. Sadly however, Anna escaped one day and was not seen again.
The Siberian Cupcakes - Sophie, Boris, Maks, Viktor and Mikhail, were also bred at the Institute and now live as ambassador animals at the JAB Canine and Education Centre in the USA. In the videos below, they can be seen assisting in research that will help further scientific understanding of domestication, the red fox genome and disease development in both humans and animals.
To date, there are no Russian domesticated foxes in the UK. However, they are available for purchase for those with the knowledge, means and funds. It costs around £15-20k to purchase and import a domesticated pet fox, which is a stark difference from the cost of obtaining a regular farm fox.
Pet Foxes in the UK
The silver foxes kept in the UK are not "domesticated pets" as they have not been selectively bred for tame behaviour towards humans until recently. They are instead, "domesticated farm animals" that have been selectively bred for coat colour and quality only. These farm foxes are not the same as the experimental foxes people think of when pet foxes are discussed, nor are they the same as the native wild animals that are kept as pets because they cannot be released.
While they are often compared to dogs and cats, silver foxes do not behave like either. Instead, their behaviour is uniquely vulpine; independent, strong-willed and defensive. Which is why keeping foxes is considered a specialist hobby for those with specific interests in exotic animal education, management and behaviour. Temperament-wise, farm foxes could be considered similar to those "unselected foxes" in the domestication experiment, which were selected for neither tame nor aggressive behaviour and displayed traits from both the tame and aggressive groups, (vocal behaviour in tame, aggressive and unselected foxes).
It requires a lot of time, knowledge and resources to keep exotic pets correctly. Out of all the exotic pets kept, foxes are one of the more difficult species to keep due to their curious and cunning nature. They have many natural behavioural traits that most would consider undesirable in a pet, from their pungent smell to their destructive and territorial tendencies. They are long lived (living up to 10-12 years in captivity), are great escape artists (requiring a secure enclosure) and they are difficult to lead and litter train. They also require a specialist diet, specialist vets and lots of species specific enrichment.
However, for specialist keepers prepared to dedicate their lives to gaining knowledge and understanding on these animals, they can be fun and fascinating companions, as demonstrated below;
- Protection of Animals Act 1911
- Performing Animals Act 1925
- The Pet Animals Act 1951
- The Abandonment of Animals Act 1960
- Wildlife & Countryside Act 1981
- Wild Mammals Protection Act 1996
- Fur Farming (Prohibition) Act 2000
- Animal Health and Welfare (Scotland) Act 2002
- Protection of Wild Mammals (Scotland) 2002
- Fur Farming (Prohibition) (Scotland) Act 2002
- Hunting Act 2004
- Animal Welfare Act 2006
- Infrastructure Act 2015
- The Animal Welfare (Licensing of Activities Involving Animals) (England) Regulations 2018
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Anomalous Red Foxes In the UK
A catalogue of videos of anomalous Red foxes reported in the UK: