How to Tame a Fox and Build a Dog

EXCERPT

BY LEE DUGATKIN AND LYUDMILA TRUT

In 1959, Dmitri Belyaev and Lyudmila Trut began one of the longest-running experiments in biology. For the last 58 years they have been domesticating silver foxes in Novosibirsk, Siberia, and studying evolution in real time to better understand how dogs were domesticated from wolves. By 1974, after about 15 generations during which they had selected the calmest and tamest foxes to parent the next generation, Lyudmila and Dmitri had a population that was on the fast track to domestication. These foxes were markedly tamer than the ones that parented the first generation, and they were beginning to not just behave like dogs, but to look eerily dog-like.

Right from the start Dmitri had predicted that even if foxes were selected strictly based on tameness—how calm they were when interacting with humans—he and Lyudmila would see other traits appear in their domesticated foxes. Many domesticated species share a common set of traits that includes floppy ears, curly tails, and extended reproductive periods: together these traits are referred to as the domestication syndrome. Dmitri had hypothesized that selection for tameness was key to the domestication process and that the other traits associated with the domestication syndrome were genetically correlated (how, he was not sure) with tameness. Even a casual glance at the foxes in 1974, with their floppy ears and curly tails (wagging in joy as humans approached) provided glaring support for this prediction. And the vaginal smears that Lyudmila had taken since the early 1960s indicated that that tame females had also extended their period of estrus.

While they were always looking for other traits associated with domestication to appear, no one on the fox research team was a psychologist, and so initially they had not given much thought to the effect that the process of domestication might have on intelligence. That would change, first as a result of anecdotal observations Lyudmila would make, and then later based on experimental work.