Domesticated silver fox

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2009)

The domesticated silver fox is the result of nearly 50 years of experiments in the Soviet Union and Russia to domesticate the silver morph of the red fox. The breeding project was set up in the 1950s by the Soviet scientist Dmitri Belyaev. As a result of selective breeding, the new foxes not only have become tamer, but more dog-like as well.

The domesticated foxes exhibit both behavioral and physiological changes from their wild forebears. They are friendlier with humans, put their ears down (like dogs), wag their tails when happy, and have begun to vocalize and bark like domesticated dogs. They have also developed color patterns like domesticated dogs and have lost their distinctive musky 'fox smell'.

Initial experimentation

The experiment was initiated by scientists who were interested in the topic of domestication and the process by which wolves became tame domesticated dogs. They saw some retention of juvenile traits by adult dogs, both morphological ones, such as skulls that were unusually broad for their length, and behavioral ones, such as whining, barking, and submissiveness.

In a time when Lysenkoism was official state doctrine, Belyaev's commitment to classical genetics had cost him his job as head of the Department of Fur Animal Breeding at the Central Research Laboratory of Fur Breeding in Moscow in 1948. During the 1950s, he continued to conduct genetic research under the guise of studying animal physiology. This was more acceptable to the Communist Party, which wanted to improve humans.^{[1][specify][Need quotation on talk to verify]}

Belyaev believed that the key factor selected for domestication of dogs was not size or reproduction, but behavior; specifically, amenability to domestication, or tameability. More than any other quality, Belyaev believed, tameability must have determined how well an animal would adapt to life among humans. Because behavior is rooted in biology, selecting for tameness and against aggression means selecting for physiological changes in the systems that govern the body's hormones and neurochemicals.

Belyaev decided to test his theory by domesticating foxes; in particular, the Russian silver fox. He placed a population of them in the same process of domestication, and he decided to submit this population to a strong selection pressure for inherent tameness.

The result is that Russian scientists now have a number of domesticated foxes that are fundamentally different in temperament and behavior from their wild forebears. Some important changes in physiology and morphology are now visible, such as mottled or spotted colored fur. Many scientists believe that these changes related to selecting for tameness are caused by lower adrenaline production in the new breed, which causes these physiological changes in a very small number of generations, thus allowing for these new genetic offshoots not present in the original species.

The project also investigated breeding vicious foxes to study aggressive behavior. These foxes snap at humans and otherwise show no fear.

Current project status

Following the demise of the Soviet Union, the project has run into serious financial problems. In 1996, there were 700 domesticated foxes, but, in 1998, without enough funds for food and salaries, the project scientists had to cut the number to 100. Most of the project expenses are covered by selling the foxes as pets, but the project remains in a difficult situation, looking for new sources of revenue from outside funding.

On November 22, 2005, the journal Current Biology published an article about the genetic differences between the two fox populations.^[2] In this study, DNA microarrays were used to detect differential gene expression between domesticated foxes, non-domesticated farm-raised foxes and wild foxes; one set was raised at the same farm as the tame foxes, and the other set was wild. Forty genes were found to differ between the domesticated and non-domesticated farm-raised foxes, although about 2,700 genes differed between the wild foxes and either set of farm-raised foxes. The authors did not analyze the functional implications of the gene expression differences they observed.

On November 21, 2007, the journal Behavior Genetics published an article about continuing research using both the domesticated and non-domesticated foxes developed by the Institute of Cytology and Genetics of the Russian Academy of Sciences.^[3] In this paper, the authors identify a system of measuring fox behavior that is expected to be useful in QTL mapping to explore the genetic basis of tame and aggressive behavior in foxes.

See also

• Domestication
• Experimental evolution
• Neoteny

References

1. ^ Full text of EARLY CANID DOMESTICATION: THE FARM FOX EXPERIMENT, by Lyudmila N. Trut (1999)
2. ^ Jazin et al.: "Selection for tameness has changed brain gene expression in silver foxes." Current Biology, Vol. 15, R915-R916, November 22, 2005, DOI 10.1016/j.cub.2005.11.009
3. ^ Kukekova et al.:"Measurement of segregating behaviors in experimental silver fox pedigrees." Behavior Genetics, Vol. 38, Number 2, March, 2008, 0001-8244 (Print) 1573-3297 (Online), DOI 10.1007/s10519-007-9180-1

External links

• Early Canid Domestication: The Fox Farm Experiment, by Lyudmila N. Trut, Ph.D.
• An Additional NYTimes Article
• Fox Domestication: website from Cornell University with detailed information (videos and articles)
• New York Times article
• CBBC News Article
• Press release from Eurekalert.org
• Tame foxes in North America
• New Scientist article