The Curious Case of the Friendly Russian Foxes

Dr. Lyudmila Trut and a human-friendly fox, 1974.

Foxes have a reputation for being elusive, canny, shy. . . in other words, foxy. Wild foxes in captivity are innately aggressive and fearful of humans – not friendly at all. With a great deal of patience, you may be able train one to be more docile, but it would not be a dog-like pet. However, if you have a slightly weird desire for a pet fox that will behave more like a cocker spaniel than a wild fox, you may be able to get one from a genetic research institute in Russia. The institute can sell you a fox which actually seeks human attention, which will lick your face, which will show you doglike devotion (email or Or you can contact one Mitchel Kalmanson, a real estate agent in Maitland, Florida, which is just north of Orlando. Mr. Kalmanson occasionally travels to Russia to purchase a small number of such foxes. (He keeps a few for himself, as well as lions, tigers, cougars, and, until it died recently, a leopard.) Kalmanson may have a friendly Russian fox for you, but it will cost you north of $9,000 US. Where did those foxes come from?

The creation of friendly Russian foxes

The people-friendly foxes originated at the Laboratory of Evolutionary Genetics, which is in The Institute of Cytology and Genetics (IC&G), in Novosibirsk, Russia. The IC&G was established in 1957, when Russia was still part (the dominant part) of the Union of Soviet Socialist Republics — the good old USSR. It was part of a planned multifaceted “city of science” in Siberia, in which the government of the USSR wanted to see all sciences develop to a level that could challenge the West.

Soon after the IC&G was established, Academician Dmitri Belyaev introduced the project that ultimately led to the breeding of friendly foxes to his laboratory there. The nominal aim was to try to produce foxes that were easier to manage on the fox fur farm, but Belyaev had a sly idea that took him into the field of Mendelian genetics, which at that time was forbidden territory in the USSR.

The experimental procedure pursued by Belyaev was straightforward. His student assistant was Lyudmila Trut, who had helped start the project some years earlier and would continue it after Belyaev died in 1985. He sent her to a large commercial fox farm to try to obtain some silver foxes that were less aggressive and fearful of humans that most. Silvers are variants of the red fox, and are desirable in the fur industry. The work had begun in 1952, but in 1959 the project was moved to a “fox farm” at the IC&G. Foxes can produce a litter within about a year, so each year would produce another generation. To try to produce foxes that were friendlier and easier to handle, they were selected for their willingness to approach and interact with a handler.

The handlers had categories for the foxes. Those that remained aggressive, that cowered at the back of the cage, that attempted to bite the heavy glove of the handler, were Class III. Class II animals would tolerate handling, although they showed little desire for human interaction. And Class I were foxes that not only had lost their aggressive tendencies, they explored human contact. The 20% or so of the friendliest foxes were bred to each other every year, to try to develop the “friendly” behavior. This selection was repeated down through the generations.

An important feature of the program was that no effort was made to train or interact with the foxes except during testing. This was to be a genetic experiment, not a test of the kind of Lamarckian genetics favoured in the Soviet Union at that time (more about that later).

After just a few generations, it was clear that a subgroup of Class I was emerging that was downright eager to interact with humans. The experimenters called them Class IE (for elite). Progress was astonishing. In 1966, seven years after the program at IC&G began, 1.8% of the foxes were in Class IE. By 1970, with generation 10, that number was 17.8%, and it continued to grow. In 2002, after 42 generations, 71% of the selected foxes were Class IE. The genetic selection for friendly foxes was a success, and it happened remarkably quickly. The story of their development is told in a 2017 article in American Scientist by Drs. Lyudmila Trut and Lee Dugatkin (1).

After 1970, the scientists also began to group and interbreed the least friendly, most aggressive, foxes. The difference between them and the friendly, dog-like Class IE foxes is remarkable. A video clip on YouTube shows the wide divergence in behavior between the wildest, and most dog-like, foxes.

Evolution on steroids

Two potential impediments to Belyaev’s work existed in 1959. First, there was no assurance that genetic selection could produce a behaviorally changed fox during anyone’s lifetime. If the agencies that fund scientific research today were controlling the funding for Belyaev in 1959, he would have been out of luck. The science wasn’t against him, but it wasn’t strongly enough for him either. The other barrier was political, and that one almost sank him at the start, as will be described later.

Genetics underwent a revolution during the first decades of the twentieth century. Darwin had proposed that evolution required organisms to change in order to be selected for advantage. But Mendel had shown that the units of biological inheritance, what we call genes, were unchanging over the generations. If biological traits were the products of unchanging genes, but had to change to allow for evolution, there was a conundrum. The problem was solved by the discovery that genes can change by undergoing mutation. Darwin’s and Mendel’s theories could be compatible.

This new view of genetics, the “Modern Synthesis”, needed another feature to account for the rapid rate of change that sometimes happened in the genetics of populations. Mutations happen too slowly to account for some observed changes. A solution was discovered through careful experimental studies. This was the work of Theodosius Dobzhansky, a young geneticist who had left the Soviet Union for postdoctoral studies in the United States in 1927, and never returned. Dobzhansky studied the genetics of a particular strain of fruit fly. He captured flies all over the United States and analyzed their genetics, and discovered that there was already a high level of genetic variation within that population. Subsequent work, including recently the DNA sequencing of the human genome, has solidified that view. We are all accumulations of genetic changes. Even if two people are identical to the 0.1% level, that leaves a difference of 3 million base pairs (that’s just a simple-minded calculation; the real genetic world is enormously more complex).

This final addition to The Modern Synthesis could account for fast evolution. It wasn’t necessary to wait for mutations to slowly accumulate and provide the selectable characteristics. Individuals with genetic variations of particular genes already existed in the population at large. They could be selected relatively quickly by a change in the environment. And if individuals with different genes that each contributed to advantage were mated, the new genetic configuration would proliferate even more rapidly. This is apparently what was happening with Belyaev’s foxes. “Friendly” traits already existed in the population, and were being selected. Breeding individuals with various such traits quickly led to increasingly friendly foxes.

There are two illuminating features of the development of friendly foxes. Belyaev and his colleagues noticed that it takes place in stages. Loss of aggression might happen first, and only later would the loss of fear of humans, and the desire to interact with them, be seen. It became clear that the development of friendliness is genetically complex, and involves several stages, which might include, for example, genetic changes in the levels of hormones that stimulate aggression.

The other feature was that friendly foxes often had physical attributes that we associate with dogs, including curly tails, different facial configurations (shorter snouts, which are cuter, more puppy-like) and even sometimes floppy ears. There appeared to be a linkage between the genes responsible for friendly behavior and physical appearance. These linkages, and the genes responsible for them, probably also exist in dogs, and are currently the subject of genetic studies in both species.

Political Science in the USSR

When Belyaev began his groundbreaking research program on foxes, he knew that he had to be very careful. Genetic science in the USSR was not a happy place at the time. During the early years under the dictator Joseph Stalin, the 1920s and 1930s, there were horrific famines, and literally millions of people died of starvation. The political leadership looked for help in improving crop yields from agronomists, and thought they had found it when an uneducated, but slick, individual named Trofimov Lysenko caught their attention. He claimed, without real evidence, that he could develop crops that would ripen earlier and produce more food under stressful conditions. His work flew in the face of the mainstream, Mendelian genetics practiced in the rest of the world. He said he could induce cold hardiness, for example, by soaking wheat seeds in cold water, and that the wheat grown from those seeds would pass on the cold-resistant trait. If this sounds familiar, it is similar in principle to what the early French naturalist Lamarck had proposed, well before there was any contrary evidence from the work of Mendel.

The political leadership bought what Lysenko was selling, and saw it as a way of providing enough food to prevent further starvation (it wasn’t; and when they sold the story to China it subsequently underwent its own agricultural collapse, with tens of millions of people starving to death). So the all-powerful Soviet leadership gave Lysenko almost unlimited control over Soviet biological science, and he proceeded to dismantle the scientific culture of the USSR. He destroyed Russian population genetics, which was one of the strongest such groups in the world. Dobzhansky, who became a scientific superstar in the USA after his studies on fruit flies, was one of the lucky ones who escaped. Before leaving the Soviet Union, he was influenced by the population geneticist Sergei Chetverikov, whose brilliant work was little known in the West because he published only in Russian. Chetverikov wasn’t as fortunate as Dobzhansky — he was arrested in 1929, imprisoned for 5 years, released and re-employed, and then dismissed in 1948 because of Lysenko’s influence. Other Soviet geneticists were either fired and allowed to starve to death, or imprisoned, or shot. It was midnight for Soviet genetics.

Lysenko (far left) and Stalin (far right) at the Kremlin in 1935.

Lysenko grew more and more powerful, even as his scientific credentials were seen to be more and more nonexistent by outside observers. Consistent with communist dogma, he was sure that any trait could be induced by environmental pressure alone and then passed down through the generations; there was no need for “bourgeois” (Mendelian) genetics. According to him, it was an invention of Western capitalists under Jewish influence.

Lysenko’s grasp of science is illustrated by a story from a visit he paid to the Soviet Academy of Medical Sciences. There, he disputed the very existence of DNA (this was after the invention of the double-helical model, and its ability to explain genetic replication). The director, biochemist Vladimir Engelhardt, showed him a sample of dried DNA in a tube. Lysenko sneered “Ha! You are speaking nonsense! DNA is an acid. Acid is a liquid. And that’s a powder. That can’t be a DNA!”

Lysenko became dictator over biological research in the Soviet Union, with Stalin’s complete backing (and what Joseph Stalin wanted, he almost always got). In 1948, the Supreme Soviet, the annual meeting at which the dictates of the Communist Party became law, ruled that dissent from Lysenko’s theories of environmentally acquired biological inheritance was illegal. After Stalin died in 1953, scientists began to breath a little easier, thinking that Lysenko’s days were numbered. They were, but the number wasn’t zero — his influence diminished, but he wasn’t officially fired until 1965. And the existing political powers, including Premier Nikita Khrushchev, had grown up in the Lysenkoist world, and still assumed he was right.  Mendelian genetics was not yet politically acceptable when Khrushchev paid a visit to IC&G in 1959, shortly after Belyaev’s fox breeding program started.

At that moment, Belyaev’s program was teetering on the brink. Khrushchev was disgruntled to find that there were geneticists at IC&G. He threatened to close down the whole “science city” in Novosibirsk, of which IC&G was a part. Fortunately, this didn’t happen. Credit in averting this catastrophe is given in part to Khrushchev’s daughter Rada, a journalist who was trained in biology, and who was brave enough to write that Lysenko was a fraud. Khrushchev backed off, probably because she was his daughter. But he felt he had to do something, so he fired the head of IC&G. He was replaced, ironically, with Belyaev, the deputy director, who was just starting his radical experiment in population, Mendelian-based, genetics. Ironic, too, was the fact that Dmitri Belyaev’s own brother, also a geneticist, had died in prison after being purged by Lysenko.

The damaging effects of political leaders with great power who disbelieve science are well illustrated by the horrors of Lysenkoism. But these conditions are not exclusive to the old Soviet Union. Today’s climate change sceptics and anti-vaxxers are members of the same tribe, and that membership extends to the highest levels of political power in some countries. Nothing good can come of that.

Despite the clear demonstration that Lysenko was a destructive idiot and had nothing useful to contribute to science, his reputation, remarkably, “. . . has enjoyed a renaissance in Russia over the past few years. Several books and papers praising his legacy have appeared, bolstered by what the article calls ‘a quirky coalition of Russian right-wingers, Stalinists, a few qualified scientists, and even the Orthodox Church.'” (2)

What does it all mean?

The results of Belyaev and Trut’s work unequivocally indicate that behavior has a genetic component. There are certainly environmental factors, including very basic ones such as physical health and proper nutrition, which can influence behavior. And there is probably an element of chance in the development of any complex behavioral trait (or in any case, what appears to be chance).

But there is a genetic component, as seen by the ability to select for and enrich the “friendliness” trait by breeding. Of course, other data indicate the same thing, including the classical studies on human identical twins reared apart. In that case, behavior, intelligence, even religious belief, showed greater similarity between the twins, who are genetically essentially identical, than between siblings who don’t share all of their genes (3).

So genetics plays a role in behavior, but not the only one. Furthermore, most behaviors are probably due to a number of genes, and we may never fully understand, say, schizophrenia at the molecular, genetic level. The genetic complexity of “friendliness” in foxes was clearly evident in the progressive, step-wise development of the final phenotype.

Go to Latest Posts



  1. Dugatkin, L., and Trut, L. “How to Tame a Fox and Build a Dog.” American Scientist 105 (2017): p 240. Available online here.
  2. Kean, S. “The Soviet Era’s Deadliest Scientist Is Regaining Popularity in Russia.” The Atlantic December 19, 2017. Available here.
  3. Bouchard Thomas, Lykken David, McGue Matthew, Segal Nancy, and Tellegen Auke. “Sources of Human Psychological Differences: the Minnesota Study of Twins Reared Apart.”Science 250 (1990): p. 223-228.