Selective Breeding

Cass Sunstein’s latest column at Bloomberg, “How Dogs and People Ended Up Ruling the World”, is almost right. Here’s his thesis:

Why do dogs flourish as wolves struggle to survive? Why are we the only remaining humans?

New research suggests that these diverse questions have a single answer.

In brief: Dogs are far less likely than wolves to respond to challenges with violence (or by running away). Or, in more technical terms, they show low levels of “reactive aggression” in social interactions.

As compared to extinct human species, Homo sapiens show precisely the same thing. As a result, we — you and I — are uniquely capable of trust and cooperation. That’s the basis of our evolutionary triumph.

Where he’s wrong is that natural evolution did not produce the relative “docility” of both dogs and humans. It is the result of selective breeding.

We don’t really know how dogs developed from the small Middle Eastern wolves from which they are believed to be descended but we think it happened something like this. Human beings and wolves occupy similar niches in the ecosystem. We are both cursorial hunters who hunt in packs with similar habitats and ranges. It was inevitable that our paths would cross. A less wary, more “docile” wolf would occasionally wander into a human campsite and less wary and frightened human groups would let them. The humans might actually feed those wolves. That would attract more of those less wary and more docile wolves, drawn by the food. Humans would encourage mating between less wary, more docile male and female wolves, resulting in even less wary, more docile offspring.

In technical terms we were selecting wolves for lower cortisol production and neoteny. Eventually those wolves became dogs.

Humans and dogs make a great team. Not only do we occupy similar ecological niches and have similar sociability, we have overlapping capabilities. Dogs have better senses of smell; we have better vision. We hear in a lower register; dogs hear in a higher one. Dogs are crepuscular; humans are diurnal. Dogs have surer footing; we have hands. They run faster; we have greater endurance. Our abilities are complementary. One of the things that means is that humans who were able to tolerate and live with dogs did better than those who couldn’t.

We didn’t just guide dogs’ evolution. Our two species co-evolved.

3 comments… add one
  • James P Kirby Link

    What I find interesting is the claim that a man has the endurance to track on foot and capture any land animal, partly on account of his ability to carry his food, though the attempt can be frustrated by the ability of a tired elk, for example, to lose himself in a herd.

  • Greyshambler Link

    Never really been a dog lover because they go overboard, we have a Doberman and if I let her, she’d lay on top of me 24/7. Feel like full time job avoiding her.

  • steve Link

    I thought the idea of persistence hunting was controversial.


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