Tame Silver Fox

The Tame 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. Notably, the foxes not only become more tame, but more dog-like as well: the new foxes lost their distinctive musky "fox smell", became more friendly with humans, put their ears down (like dogs), wagged their tails when happy and began to vocalize and bark like domesticated dogs. The breeding project was set up by the Soviet scientist Dmitri Belyaev.

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History

Initial experimentation

Scientists were interested by the topic of domestication, and how wolves were able to become tame, like 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 behavioural 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]

Belyaev believed that the key factor selected for domestication of dogs was not size or reproduction, but behaviour; specifically amenability to domestication, or tamability. More than any other quality, Belyaev believed, tamability 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 tame foxes which are fundamentally different in temperament and behaviour from their wild forebears. Some important changes in physiology and morphology are now visible, such as mottled or spotted colored fur.

The project also investigated breeding vicious foxes to study aggressive behavior. These foxes snap at humans and otherwise show fear.^[2]

Current project status

Following the demise of the Soviet Union, the project has run into serious financial problems. In 1996 there were 700 tame foxes, but in 1998, without enough funds for food and salaries, they had to cut the number to 100. Most of their expenses are covered by selling them as pets, but they remain 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.^[3] In this study, DNA microarrays were used to detect differential gene expression between tame foxes, non-tame farm-raised foxes, and wild foxes; one set was raised at the same farm as the tame foxes, and the other set was wild. 40 genes were found to differ between the tame and non-tame 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.

See also

• Domestication
• Neoteny

References

1. ^ http://reactor-core.org/taming-foxes.html
2. ^ Popsci.com
3. ^ 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