Early Canid Domestication: The Farm-Fox Experiment

Prompted by a recent issue of the NYRB, I bought a copy of reference 1. Which turned out to be a very nicely produced book from the University of Chicago Press - with the fact that this is far more often true of books manufactured in the US than of books bought here continuing to both irritate and puzzle me.

Also an excellent bit of popular science, combining the story of a fascinating bit of research into the domestication of foxes with that of science in the Soviet Union at about the time that the grip of Stalin and Lysenko was being shaken off. Also the time of the cold war and I was reminded of the waste and wasted opportunities resulting from so many decent and well-meaning people on both sides of the fence being locked into the adversarial politics of their masters.

I share a few more facts.

Dogs were first domesticated, almost certainly from wolves, about 15,000 years ago. Modern farm yard animals followed about 5,000 years later.

Russians have farmed silver foxes, close relatives to wolves, for their pelts, on a large scale for a long time. Much interest in how to do better. So a convenient base for a large scale experiment in selective breeding.

Selective breeding for tameness, hypothesised to be the key to domestication. With this selective breeding for a behavioural trait resulting in a cascade of changes in the expressions of all kinds of existing genes, resulting in heritable change orders of magnitude faster than could be achieved by mutation. An idea which was rather ahead of its time back in the 1950s.

Some of these changes were to do with hormones, one of which was melatonin, mixed up with the pineal gland which I might have mentioned at reference 3, but did not. Melatonin does various things, but one of them is tracking the seasons - important for the timing of mating - by tracking the amount of light. Which gives us the connection to the extra eyes of reference 3.

One result of which was changing the rate of development which resulted in turn in the retention into adulthood of traits and features which had before been dropped - with a lot of the behaviours of adult pets being the same behaviours that we value in infant humans.

Domestic animals are usually sociable, both with each other and with humans. While wolves are very sociable among themselves, but very aggressive towards humans. Bonobos are even more sociable among themselves. While chimpanzees have a busy, but sometimes very violent social life. Maybe domestication parallels our evolution from something like a chimpanzee to what we have become today. Some people are very keen on something called self-domestication.

In the case of the domesticated foxes, there was also a modest reduction in the difference between males and females, with the males heading towards the females rather than the other way around.

Some talk of something called the good object test. For example, hide a snack under one of two similar boxes and point to the one where the snack is. The tame foxes got the idea, but the wild ones did not. Dogs, it seems, are very good at this game and its variants. All because, being domesticated they are very good at reading the cues from the humans. With a famous example of how not to do such experiments being the horse called 'Clever Hans'. I suspect that our youngest grandchild, at 18 months, would already pass this test.

Some speculation about trying the same thing with chimpanzees. Speculations which are unlikely to be turned into experiments, partly because of the time and expense involved (with chimpanzees breeding at ten years compared with the foxes' one year), partly because of ethical concerns.

For those who prefer something with a more scientific flavour there is also reference 2, free to download if you know where to look. Much shorter and still accessible to the general reader, such as myself. I offer two quotes:

‘… After 12 generations of selective breeding, the basal levels of corticosteroids in the blood plasma of our domesticated foxes had dropped to slightly more than half the level in a control group. After 28 to 30 generations of selection, the level had halved again. The adrenal cortex in our foxes also responds less sharply when the foxes are subjected to emotional stress…’.

‘… By intense selective breeding, we have compressed into a few decades an ancient process that originally unfolded over thousands of years. Before our eyes, “the Beast” has turned into “Beauty,” as the aggressive behavior of our herd’s wild progenitors entirely disappeared…’.

PS: interested to see that reference 1 saw fit, in 1999, to include drawings taken from photographs, one of which is snapped above. Was this just the different habits of scientists from the east or a respect for the greater clarity of the drawn picture? The advantage of a diagram over a photograph, with a drawing from a photograph getting the best of both worlds?

Reference 1: Early Canid Domestication: The Farm-Fox Experiment: Foxes bred for tamability in a 40-year experiment exhibit remarkable transformations that suggest an interplay between behavioral genetics and development - Lyudmila N. Trut – 1999. Open access.

Reference 2: How to Tame a Fox (and Build a Dog): Visionary Scientists and a Siberian Tale of Jump-Started Evolution - Dugatkin, Lee Alan and Trut, Lyudmila - 2017.

Reference 3: http://psmv3.blogspot.co.uk/2018/04/chief-architect.html.