It was the height of the Cold War between the Soviet Union and the United States. In the dark of a harsh Russian winter night, Sean Connery silently parachuted in to the U.S.S.R. government compound. After tearing off his tuxedo to reveal a darker, stealthier tux underneath, he pulled his Walther PPK pistol from its holster and proceeded towards his target. He darted from tree to tree, never taking his eyes off the guards patrolling the facility. Finally, after hastily knocking a guard out and stashing his limp form in the bushes, the British secret agent slipped in to the building. He had found his mission objective, the reason he was risking his life for his country and for the free world. Looking around him, he saw cages and cages of… foxes.
Or, at least, something like that, sort of, might have been the scene in the 1960’s if James Bond were real and the British intelligence agencies had wanted to spy on one of the more surprising biological experiments conducted in the 20th century. The compound in question would be the Institute of Cytology and Genetics, located in Novosibirsk, Siberia. And while it might not have had guards and foreign spies duking it out in the darkness, it really was home to a bunch of foxes that were teaching us something surprising about evolution. They were teaching us about the genetic and evolutionary nature of domestication in animals, and it was actually a lot easier than anybody expected.
But first, a bit of backstory. The Soviet Union under the leadership of Joseph Stalin had been in the grip of a, frankly, bizarre backlash against the study of genetics and Darwinian evolution. Mendel was a dirty word from the 1930’s up through the 50’s, and if you don’t know who Mendel was… well what a good little Communist you would make! The story of this period of anti-science sentiment in the USSR is, frankly, fascinating and will probably make its way into an entire episode of its own some day. But, for now, the gist is that genetics and Darwinian evolution just weren’t very communist or Marxist, and at that time, everything in the U.S.S.R. had to prove that communism was the superior philosophy, even science. The notion that a single, random mutation in one gene in a single individual could eventually alter the nature of an entire species went entirely against the belief that progress could only come about through the hard work of the collective.
And so, for years and years, genetics was essentially illegal in the Soviet Union. Soviet scientists had a choice: pretend that DNA didn’t exist, or be punished. To their great credit, many stood by the science, even non-geneticists, and so they were all fired. Or imprisoned. Or killed. Martyrs for science. During this period, a guy named Dmitry Konstantinovich Belyayev lost his job because the Communist Party eventually figured out that his studies of the physiology of mammals were actually about genetics. You’ll notice I said “lost his job” and not “slowly starved to death over the course of several years in a labor camp”, and so he was very lucky. Belyayev still wasn’t deterred, however. The anti-science politics of the times infuriated him. He kept secretly studying and theorizing about genetics for the next ten years, still claiming it was actually physiology. Eventually, a few years after Stalin’s death, the political climate had cooled off a bit. He was eventually able to start openly researching genetics again. And he was eager to finally start looking at a problem that had been nagging at him for years: what the heck is up with dogs?
Who let the dogs How were the dogs let out? Of the wolf?
You see, Belyayev, along with some random no-names like Charles Darwin, had wondered for a while why every species of domesticated animal had physical traits that were different from their wild ancestors, but which offered no obvious benefit to their domesticated life. Think of floppy ears in dogs, curled tails in pigs, or spotted color patterns in basically all domesticated animals. Not all members of the domesticated species have these traits… many dogs have ears that stand up straight, and plenty of domesticated animals have color patterns that resemble their wild ancestors. But every domesticated species does seem to have at least some members with some of those traits that are rare or non-existent in the wild.
And what puzzled Belyayev was, it doesn’t seem like they offer a practical benefit. Remember, these are generally animals that were domesticated for practical purposes. Why would our ancestors have intentionally tried to breed pigs that had floppy ears, spots, and curly tails, when they were just going to eat them anyway? And yet there they are. Not all of them, but they’re not hard to find. Something weird seemed to be going on. Belyayev figured these traits must be accidental, that when our ancestors selected individual animals that were easier to work with, there were these other odd physical traits that inevitably got carried along for the ride. But there was no way to go back in time and prove it by watching people domesticate, say, dogs from wild wolves.
So Belyayev decided he would try to re-domesticate dogs himself. No big deal, right? It just took… well, we don’t even really know how long it took for dogs to become domesticated originally. It happened tens of thousands of years ago, but most folks at the time generally assumed it was a process that had taken hundreds or even thousands of years to get from the grey wolf to a pomeranian. That Belyayev wanted to even try this was… well ambitious would be one word. Kind of crazy would be another. After all, he had no idea how long he would have to run this experiment before it yielded measurable results. If it ever did. He might die before it really went anywhere. But Belyayev said, screw it, I’m gonna figure this out even if I do die first. Except, you know. He said it in Russian.
But, there was another problem, besides the fact that this was going to be a very long experiment. Getting enough wolves to try to breed and domesticate in captivity was going to be difficult. They would be difficult to house and expensive to feed. So, Belyayev went for the next best thing: red foxes. The red fox had already been bred for about 50 years in farms for their pelts. These animals were actually called silver foxes, and not just because they looked like George Clooney. They were actually melanistic mutants, meaning that they had a lot more of the pigment melanin than normal, giving them a black and grey coat that was highly sought after for fur coats at the time. But otherwise, Belyayev reasoned, they were about the same as wild red foxes. They certainly weren’t tame. Foxes are related to wolves, but they’re a lot smaller, easier to feed and house, and commercial fur farms had as many as he could possibly want, without needing to go traipsing around the wilderness setting hundreds of live traps. So, to reinvent the dog, Belyayev set out to domesticate the red fox.
What does the fox… umm… say. Sorry. It was obligatory.
First he and his colleague Lyudmila Trut (who, by the way, seems to have done most of the actual work), had to pick their initial breeding stock. This was a pretty simple process. They visited fur farms and went from cage to cage, sticking a gloved hand in to see how the foxes reacted. Those that bit or hid in the corner were left alone. Those that allowed themselves to be touched or that at least didn’t seem afraid were picked for the project. If tameness were a genetically determined trait that you could select for, then they should be off to a good start. They then set about breeding these animals back at his Siberian lab. You know, the one that I want to pretend had British secret agents snooping around it. To make sure that they were actually observing inherent, genetically based tameness, and not learned behavior, they kept human contact to the minimum needed to care for them.
When new pups were about a month old, they started testing them for tameness. A researcher would try to hand feed them, pet them, or hold them if possible. They also would sit in an enclosure with a group of the young foxes and observe which ones were curious and came up to investigate the human, and which avoided them and instead hung out with the other foxes. They received a score based on these reactions, and the tests were repeated monthly until it was time to select the next generation of breeders. Again in between tests, nobody interacted with them beyond what was absolutely necessary, to make sure they weren’t just getting used to people. At around 8 months, sexual maturity for red foxes, the foxes that scored the highest on the tameness evaluation were allowed to breed together, while also trying to minimize inbreeding. Then when those pups were about a month old, the process started over, so that each generation, only the foxes that were the most naturally tame were allowed to breed. Each generation took around a year.
The results surprised everyone. Within five or six generations, they started seeing foxes being born that inherently had some dog-like behavior. A few foxes in those generations were not only willing to be touched and handled, they actually seemed to like it. They licked the human researchers, wagged their tails when they saw them, and whined when they left. Remember, the foxes only saw these researchers once a month for a very brief period of time. This wasn’t the result of intense bonding and familiarity. After a few more generations, physical differences started to show up in the tamest foxes as well.
Fox pups have floppy ears when they’re born, and they eventually straighten up. But the ears of these tame foxes were taking longer than usual to perk up. Their tails were also less rigid and had more of a tendency to curl up. Then foxes with spots or mottled coloring started showing up. Each generation, both the tame behavior and these unintended physical traits became more and more common. Meanwhile, they were getting ever tamer. They eventually had to add a new category to their tameness evaluation, because some foxes started to eagerly seek out humans. When researchers went in to an enclosure to see how the foxes reacted to them, these “elite” foxes, as they were called, didn’t just allow themselves to be picked up. They begged for it. They leapt into people’s arms, they pawed at them and whined for attention. They were acting kind of like dogs.
Happy little domesticated foxes
Just as significant, there were chemical changes going on inside the fox’s bodies. Their serotonin levels increased compared to wild foxes. Serotonin, as you may know, is what we popularly refer to as the “happy” brain chemical, because it is responsible for mood regulation as well as many other things, and problems with serotonin levels are one cause of depression in humans. Meanwhile, their adrenaline levels were dropping, and their adrenal glands actually shrank in size. Adrenaline levels are associated with aggression, so between the two of these changes, the foxes were becoming neurochemically hard-wired to be friendlier. At the same time, their stress hormones were also decreasing. And remember… this was not what Belyayev and Trut were selecting for. They weren’t measuring the neurotransmitter and hormone levels of each pup and selecting the ones based on those values. They were selecting for tameness. These other changes seem to just go along with that behavior.
And this experiment that was started in 1959 is still going on. They’re at about their 60th generation of fox, and Belyayev has since died, his experiment outliving him. Trut runs the joint now at a spry 85 years of age, and she is still publishing research on the foxes. Nearly all the foxes born at the lab now are pretty tame, and most are “elites”. They’ve also shown some more subtle physical changes. Their faces are slightly shorter and rounder, their legs a little shorter and stouter. They’re retaining a little more of their juvenile features once they reach adulthood. In other words, they’re a little cuter than the wild foxes. Once the red fox genome was sequenced, they started digging in to the genetics of what was happening, and found that a lot of the genetic differences between wild foxes and their domesticated foxes occurred in one region of one chromosome, which they call a “hot-spot” for fox domestication. Some of the genes in this hot-spot are related to memory and learning. The domesticated foxes might be quicker learners than wild ones. Again, this is not something they were selecting for.
I do want to be clear about something though… despite the fact that I keep referring to how dog-like these foxes became, they are not actually like dogs. They still absolutely look like foxes, for one. Different coats and slightly different faces but you’d never think they were anything else. And they still act a lot like foxes. They still have a lot of wild behavior, like marking their territory with urine. And fox urine is notoriously foul smelling. You probably wouldn’t want one living in your house full time. They might be nice to have in for a visit, but if you left them alone in your house while you went out, you’d be liable to come back to a smelly disaster area. These domesticated foxes, by all accounts, are friendly and cute and fun, but that doesn’t mean they’d make a great pet.
So, anyway, what does all this mean? Well, the first obvious takeaway is, domestication happened a lot quicker than anybody predicted. Again, we’re not sure exactly what the process for domesticating dogs originally looked like, but it’s generally been thought to have taken centuries to have gotten from wolves that, perhaps, hung around human camps looking for food scraps, to animals that liked to chill by the campfire with them. Obviously, the Russian foxes had the advantage of intense, deliberate selection and controlled conditions, but still… folks were shocked. We now know that evolution and speciation can happen relatively quickly, over thousands of years rather than millions like it was once thought. But it’s still kind of amazing to see that dramatic of a shift in behavior in just six years.
What came first, the brains or the smiles?
More significantly, it demonstrates that Belyayev was on to something. He figured that, whether it was done consciously or not, the early interaction between humans and wolves was selecting for tame individuals first and foremost, and everything else that we associate with domesticated dogs just came with this behavior. And that makes sense… wolves that are just naturally afraid of humans wouldn’t stick around, and wolves that were too aggressive towards them would have been killed or driven off. If they’re dead or off in the wilderness, it’s going to be hard to domesticate them. It seems reasonable to think that the tameness had to come first, and everything else that makes a dog different from a wolf was incidental or came later. And the domesticated foxes seem to back up that idea. They weren’t selected for varied coat patterns or smaller adrenal glands. They weren’t measuring the heads of foxes and only picking the ones with shorter faces. They weren’t even choosing the smartest ones. Tamer foxes just wound up having these traits anyway. It seems to provide evidence for a domestication syndrome, a set of characteristics that tend to go along with domestication whether you like it or not, regardless of the species. This idea excited a lot of people, and provides a satisfying explanation for the existence of things like floppy ears in not just dogs but goats, pigs, and most other domesticated animals.
And here we start to encounter some of the controversy surrounding the Russian domesticated fox project. Because it turns out, nobody can agree on what a “domestication syndrome” means. Even the definition of the word “domesticated” is a bit fuzzy. And, as I said before, the traits that are thought to be part of the domestication syndrome are inconsistent. Most domesticated animals have some individuals with spotted or patchy coloration. But only some individuals. Others have solid color patterns or otherwise resemble their wild ancestors. Floppy ears and tails show up in some domesticated species, but not all. So, what exactly is included in this domestication syndrome? How do we define something that seems to shift depending on what species you’re talking about?
Then there’s the origin of the domesticated foxes themselves. Remember, the founding members of the breeding colony came from Russian fur farms. They in turn got their original animals from Canadian fur farmers, who were the first ones to manage to get foxes to breed in captivity and to start breeding the silver fox, that melanistic mutation that earned them more money than the normal red coloration. So, the animals that Belyayev and Trut had picked their tamer foxes from were already the result of 50 years of captive breeding. Belyayev thought they were close enough to being wild as to make no difference, but… were they? The fur farmers weren’t trying to tame their foxes. Nothing mattered to them except what the fur was like. They didn’t give a shit if the fox was an asshole or not, because they were just going to turn them into coats for rich people anyway. They weren’t really intentionally selecting for anything.
On the other hand… it seems unlikely that, after fifty or more generations of breeding these foxes in captivity, they weren’t changing at all. If nothing else, they were selecting for foxes that survived better in cages. Foxes with a higher tolerance for stress, maybe, or that did better on the type of food the farmers provided. This wasn’t intentional, but it seems likely that it happened anyway. And if there were any odd genes floating around by chance in those Canadian fur farms… perhaps genes for splotchy color patterns… then they might turn up in Belyayev’s domesticated foxes just by chance, not as the result of any domestication syndrome.
Oh, and in recent years, people have found old photos from those early Canadian fur farms that seem to show foxes interacting with their keepers. One is shown standing on someone’s shoulders. Now, we don’t have the context for those photos. Maybe those animals were half starved and that guy was feeding them and that’s all there was to it. Or maybe they were already halfway tame before their descendants ever got to that Siberian laboratory. It throws the whole domestication syndrome debate up in the air.
To be a domesticated fox, or to be a fashion accessory
As for the Institute of Cytology and Genetics, the Siberian lab where this has all gone down, they’ve created a bit of controversy themselves. Some of it was inevitable. After all, just because it was no longer dangerous to study genetics in the U.S.S.R. in the 60’s, doesn’t mean that politics and world events never touched the lab again. Just by nature of being in Siberia, access to the research, both physical access to the lab itself as well as getting at the data, hasn’t always been easy through the years. During the Cold War, collaboration or even communication between the laboratory and Western scientists would have been difficult if not impossible. From the outside, it was hard to tell if this was deliberate secrecy or just an accident of international politics. Not much they could have done about it, but it doesn’t help to build up trust either.
Funding for the government lab was also constant issue, especially after the collapse of the Soviet Union in the late 1980’s. To some extent they have had to provide their own funding by… well, what do you think happened to the foxes that didn’t make the cut for breeding the next generation? The ones that wouldn’t let the researchers touch them? Yeah, they were sold to the fur farms. From the standpoint of the science itself, this is irrelevant. It doesn’t affect their data or results. But for those concerned about animal rights, it’s certainly a big problem. And a lab having to support themselves by selling off parts of their own experiments just feels a bit filthy. It skirts the edges of what could be considered a conflict of interest or a bias in their research. Again, there’s no indication that this affected the actual science, but… I mean, can you imagine if Jurassic Park had sold off some of their own dinosaurs to try to make a b…
uhh hang on…
Yeah never mind, turns out they did sell dinosaurs in one of the movies. Okay, but that doesn’t make it any better!
So… nobody’s perfect. I don’t know if the domestic fox project has a fatal flaw in it’s design and execution. Their isolation from the rest of the world, until relatively recently, hurts the ability of other researchers to scrutinize their work or replicate it. I personally don’t like that they sold foxes back to those fur farms. And I definitely am not qualified to weigh in on whether or not the domestication syndrome is a real phenomenon or just a series of genetic coincidences. But one thing is undeniable: Belyayev and Trut basically domesticated the red fox in remarkably quick time, and they didn’t need to worry about anything except how willing the foxes were to be touched. The selection process was so simple, but so effective. Even if the fur farms had done some inadvertent selection ahead of time for them, that’s still a shockingly quick transformation. Natural selection is a potent and powerful force, and this proves it if nothing else does. Yes, it was an artificially focused and controlled version of natural selection, but the point stands. And the results are so delightful… happy little foxes, begging to have their heads scratched.
On that note, does anybody have Daniel Craig’s phone number? He told me he was going out to the fox lab for a “visit”. I didn’t think much of it, but I just realized that he’s the current James Bond. I need to make sure he knows that things are different now and he could probably just walk in and ask for a tour. See, I asked him to bring a domesticated fox back for me, but now I’m afraid he’s going to shoot the place up with the laser in his wrist watch or whatever and escape in a stolen fighter jet. With a cute little fox in his lap.
Eh, it’ll be worth it.