How the Silver Fox Was Domesticated
The Background on Domesticated Animals
Human beings began domesticating animals approximately 17,000 years ago, when the first wolf became a domesticated dog. Sheep, pigs, and goats followed shortly thereafter, around 9,000 B.C. From ancient times, humans have found domesticated animals to provide everything from companionship and protection (dogs) to meat and clothing (sheep and many other large farm animals).
Domesticated animals are far different from "tame" animals. While many wild animals can be tamed (as evidenced by "tamed" servals and other exotic pets), the tameness is confined to the single animal. A tamed wild animal will have offspring that are as wild as its forebears, unless they are also tamed.
A domesticated animal, by contrast, is born with an inherent tameness, which is not the by-product of training. The offspring of a domesticated animal will be as tame as its parent: domestication is a heritable trait. In other words, domestication is a genetic trait which is passed from parent to child: it is "nature," not "nurture."
How Foxes Shed Light on the Domestication Genes
The fur industry in Russia had a problem: the silver foxes bred for their fur were (justifiably) antagonistic toward their human captors. The foxes were wild and had an inherent fear of human beings, and would bite or scratch at any human approaching their cages.
The fur industry wanted to breed tamer foxes, to make the animals easier to keep and transport. Enter Dmitry Belyaev, a Russian researcher who had fallen out of favor with the new Communist government. Belyaev was interested in the process by which wolves had become dogs, and agreed to experiment with the fur industry's foxes. In 1959, he obtained 130 animals from the fur farms, and began a dual-sided experiment: to breed the most tame foxes from each generation, and to breed the most "wild" foxes from each generation.
To Belyaev's surprise, completely domesticated foxes appeared within 25 years: a much shorter time span than anticipated. The implications are that wolves were domesticated much more quickly than originally thought. Selecting for the tamest animals in each generation set of a sequence of events, which might be termed the "domestication cascade."
The Location of Belyaev's Experiment
Traits of Domesticated Animals
Anyone can determine the difference between a wolf and a dog by simply looking at the animal: dogs come in a variety of colors and coat patterns, can have floppy ears, and curly tails. By a surprising coincidence, the domesticated fox kits in Belyaev's experiment yielded the same traits.
The domesticated silver fox kits started to appear in a variety of colors: piebald fox kits appeared out of nowhere, somewhere along the ninth generation. The domesticated foxes also started displaying floppy ears and curly tails: other traits of domestication. The gene responsible for heritable tameness was also causing changes in the animals phenotype (the physical appearance of the animal). Domesticated traits include:
- Floppy ears
- Curly tails
- Shorter tails (loss of vertebrae)
- Change in vocalizations (barking)
- Less fear
- More social
- Change in coat color
Wild vs. Domesticated Silver Fox
Williams Syndrome, Foxes, and Domestication
Scientists have been studying the domesticated silver foxes to determine which genes might be responsible. A gene known as WBSCR17 has been identified as a probable gene for domestication, as dogs and wolves also differ in the expression of this gene.
Interestingly, there is a human genetic condition called William's Syndrome, which results from a mutation in the same gene. Children with William's Syndrome are extremely social, friendly, and endearing. Unfortunately, this syndrome causes cardiac problems and difficulty with abstract reasoning. In humans, the WBSCR17 gene is located on the long arm of chromosome 7, and encodes for N-acetylgalactosaminyltransferase. N-acetylgalactosaminyltransferase is a catalyst for oligosaccharide biosynthesis, which constitute hormone subunits.
The increase in friendly and social behavior in Wililam's Syndrome is an interesting correlate for the increase in friendly behavior among domesticated dogs and foxes, which harbor changes in the same gene.
The WBSCR17 gene is probably not the sole gene responsible for domestication. Researchers studying domesticated chickens have found a change in the TSHR gene: a gene responsible for the thyroid stimulating hormone receptor (a binding site for the thyroid hormone).
Some Foxes are Adopted by Russians
Why Domesticated Foxes Should Be Adoptable
Belyaev's experiment was a success, in that he discovered the mechanism for domestication was genetic and achievable in a short period of time. The domesticated foxes have an altered coat pattern, which makes the domesticated foxes unsuitable for the fur industry. The foxes are extremely expensive as pets in Russia (over $2,000 in U.S. dollars). The high cost prevents the widespread adoption of the animals, which means the expanding population at the laboratory must be culled each year. A selection takes place each year, and many of the friendly, tail wagging foxes must be euthanized.
If the domesticated foxes were allowed to become pets outside of Russia, their future would be brighter. Instead of living in rows of cages (or sold to the fur industry), the animals could be cared for in a similar manner to dogs. Indeed, the domesticated foxes have very similar traits to puppies: they lick, wag their tails, and are extremely social and friendly animals.
Buying a Domesticated Fox
Domesticated foxes are now available for purchase outside of Russia. One American distributor offers 100% domesticated foxes from the Russian experiment.The cost for purchasing a domesticated fox through a distributor is approximately $7000 for people living in the U.S.A.
Purchases may also be made directly from the Russian Institute of Cytology and Genetics, by contacting:
Ludmilla N. Trut,
Doctor of Biological sciences,
Irina F. Pliusnina.
Candidate of Biological Sciences (PhD),
Institute of Cytology and Genetics,
10 Lavrentyev ave., Novosibirsk,
Phone: +7(383) 333-38-59
Fax: +7(383) 333-12-78
Legality of Owning a Domestic Fox in the U.S.A.
In the United States, there are many laws and regulations regarding the ownership of exotic pets. 20 states ban the ownership of exotic animals. Only nine states have no laws regarding the ownership of exotics, including: Alabama, Idaho, Missouri, Nevada, North Carolina, Ohio, South Carolina, West Virginia, and Wisconsin.
Until the majority of states regard the Russian Silver Fox as a domesticated animal rather than an exotic animal, ownership of a domesticated fox may not be possible for the majority of citizens in the United States.
Domesticated Fox Poll
Would you like to own a domesticated fox?
Caring for Domesticated Foxes
Domesticated foxes can live indoors or outdoors: if kept outside, the fox should be provided with a blanket and shelter from extreme heat. Domesticated foxes kept in a house will often lie on the bed, and may use a litter box like a cat.
Domesticated foxes should be fed canned dog food (the type meant for medium-sized dogs). The addition of cabbage and carrots should help their digestive process. Tomatoes and potatoes should never be fed to a domesticated fox.
Domesticated foxes should visit a veterinarian regularly. A schedule of immunizations is typically provided with each fox, and includes vaccinations against plague, rabies, and other immunizations common to dogs.
Common health problems in domesticated foxes are gastrointestinal issues (due to diet). Rarely, pneumonia is seen among domesticated foxes.