Guarding the Fox House

A famous animal experiment is in peril, after 54 years of work.

A fox that is part of an experiment started by Russian geneticist Dmitry K. Belyaev

Courtesy Ceiridwen Terrill

The battered Volga bounces us along the buckled roads, frozen and thawed over long Siberian winters. With me in the van are geneticist Lyudmila Trut and her assistant Anastāsiya Kharlamova, whom I met earlier that morning at the Institute of Cytology and Genetics in Siberia.  Now in her 70s, Trut, a petite woman in a blue pinstripe jacket and light gray pants, peers through thick glasses, trying to read a scientific paper as we drive. A few minutes later, the driver stops at the dented metal gate to the experimental farm, and Trut leads the way down dilapidated rows of narrow barracks-style sheds, morning glories sprouting from cracks in the paved walkways. The farm houses 3,000 foxes, each open-air wooden shed holding 100 or so animals in adjacent wire cages. The three of us put on white lab coats and prepare to greet the foxes.

When I open the door to one fox’s cage, the only home it will ever know, the little guy doesn’t shrink in fear as a wild creature could be expected to. Instead he lets me scoop him up, then nuzzles my neck and licks my fingers. Kharlamova, a slim young woman with shoulder-length brown hair, explains that the fox is “emotional” because I’m giving him the attention he wants. 

Although domestication of dogs took thousands of years, Russian geneticist Dmitry K. Belyaev tried to reproduce the whole messy process in one human lifetime, eliminating all the dead ends and inefficiencies of chance and human blunder. In 1957, he began a domestication experiment with the farmed fox Vulpes vulpes, a distant cousin of the dog. In March 2011, a National Geographic article described the experiment as if it were finally on the verge of completion. Researchers were scanning the genomes of the “domesticated silver foxes,” it said, in the hopes of finding “key domestication genes.” But there’s a problem with this narrative: Even after 54 years of research, we still don’t know whether the animals have reached the original end point set out by the project’s founder.

Belyaev, who died in 1985 and left Lyudmila Trut in charge of the project, was clear about his goal: The foxes would be considered fully domesticated only when they obeyed human commands as dogs do. That part of the experiment is still unfinished. No evidence exists to tell us whether the foxes can be trained to override their instincts, the way a dog might learn to avoid defecating on the carpet, or to stay at the heel instead of running off to seek the company of other canines. Belyaev would never have called the experiment over until a whole population of foxes had shown that they were biddable, eager to please, and able to pass those qualities to their offspring. Now Trut would like to put those qualities to the test, but her experiment has stalled for lack of money. After 51 generations of foxes, the world’s foremost domestication experiment languishes. If nothing is done to save it, we’ll have missed an opportunity to understand the mechanisms of domestication, of which genetic tameness—friendly behavior that is not learned but inherited—is only one component.

Belyaev began with several hypotheses: People created the dog, and they did it by selecting—first unintentionally and then intentionally—for behavior.  He could replicate and accelerate the dog’s domestication process with the fox, he theorized, by rigorously selecting for tameness, which would eventually allow him to uncover the genetic mechanisms responsible for changing the dog’s wild ancestor into our beloved Fido. From fur farms where foxes had been bred in captivity for more than 50 years, Belyaev chose 130 of the calmest animals, descendants of foxes who’d already passed an unintentional selection test for tameness simply by surviving the original lure, capture, and confinement that literally scares some wild foxes to death. Kits born to Belyaev’s founding population and each succeeding generation of kits were subjected to a standardized tameness test, each animal ranked according to its response to a human experimenter who tried to touch and feed it. Only those foxes that showed tolerance for the nearness of people were selected and bred to produce the next generation, while fearful or aggressive animals were culled. Each generation of foxes grew more approachable, many showing doglike yearning for human contact. The experimental farm presently houses a stable population of genetically tame foxes.

Results of testing by anthropologist Brian Hare and his team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have shown that Belyaev’s foxes respond to pointing cues almost as well as dogs, which means they’re attuned to human interaction. But although we have the occasional anecdote of a fox walking on a leash or another sitting for a treat, no systematic socialization and training program has been launched to test the capacity and willingness of the foxes to respond to classic obedience cues—come, sit, down, stay, and settle— defining characteristics of a domestic canine. If fox kits are raised like dog puppies, put to the training test, and pass, then scientists would know that all the genes relevant to domestication are present in their genome. They’d just have to find them.

Unfortunately, the experiment is broke. Grant money is scarce in Russia, where economic crises hit in 1998 and again in 2008. Trut has resorted to selling some of the foxes into the exotic pet trade through SibFox Inc., a private company in Las Vegas. For $6,950, the U.S. distributor promises a tame four-month-old fox “delivered to your door in 90 days.” Since the foxes’ critical window of socialization—the period during which they form primary bonds—closes when the animals are about 60 to 65 days old, it’s no wonder the distributor advises housing the foxes in cages with bottoms or dig guards to prevent escape, because that’s what the foxes try to do. 

But the fact is, people aren’t lining up for pet foxes, and each year Trut and her team must either euthanize or sell several hundred foxes to fur farms because she can barely afford basic upkeep. As of this writing, fewer than five foxes have been sold in the United States as pets, and only a handful live with wealthy Russians. One sent to a home in Moscow went roaming and found himself a wild girlfriend whom he occasionally brought around for dinner. She wouldn’t go near the house, and he stayed only long enough to eat a bit of meat—less a pet than a roommate. Yet Trut soldiers on, trying to preserve the integrity of the genetic line in case funding should materialize for a rigorous socialization and training program. 

For the experiment to continue, fox kits would have to be systematically hand-reared and human-socialized. Then they could be trained and tested for their ability and eagerness to respond to classic obedience commands. If the foxes don’t prove trainable, then perhaps domestication, even when compressed for efficiency, takes longer than one human lifetime and is more complicated than merely selecting for a single behavioral trait. Or perhaps the dog’s ancestor possessed something unique in its genes that gave rise to our closest companion, something that can’t be replicated in the fox just because it’s a social canid. The point is, we won’t know until Belyaev’s experiment is finished. Unless the experiment is helped to reach its conclusion—to understand once and for all whether the foxes have achieved domesticity as Belyaev hoped—more than half a century of intellectual labor and the lives of more than 50,000 foxes will have been wasted.

Trut feels bad about the state of the farm and the plight of hundreds of foxes moaning and chattering for attention from their 3-foot wire cubes. On my last night in Siberia, over a meal of tsar’s hodgepodge—described in the menu as “grilled vegetables with secret sauce and garbage”—a man with his personal fifth of Beluga vodka tells me that getting by in Russia takes a lot of luck. I can’t help thinking those farm foxes need all the luck they can get. They’ve already surprised geneticists by suggesting that selection for a single behavioral trait can trigger “piggy-backing” changes in physiology and appearance, like increased levels of serotonin and piebald coats. There may be more surprises to come, but it will take a major infusion of cash, and a collaboration among scientists, adventurous dog trainers, and Lyudmila Trut to let Belyaev’s experiment—and eventually his foxes—out of the box.