Scientists used to think Stone Age people domesticated the dog by adopting wolf pups and breeding the friendliest of them, or the most obedient. But more recent thinking says dogs domesticated themselves.
Dogs were first domesticated in Europe or Asia 15,000 to 40,000 years ago. But how? The traditional wolf-breeding theory has some problems. Stone Age people might capture a wolf pup, but how could they pick the pup’s mate once it grew up? Back then, no one had a cage or kennel. They didn’t even have buildings or metal tools. Our whole species lived as hunter-gatherers, in camps that moved from place to place. So probably any wolves living with people roamed free, at least mostly, staying near the camp by choice. How then could these humans control their wolves enough to choose mates — over and over for generations?
Also, wolf-management isn’t easy. Wolves don’t obey people as readily as dogs. And pushing around a full-grown wolf can be hazardous to your health, particularly if you try to block mating — even if you’ve showered the creature with love its whole life. That’s the point of domestication: it made wolves/dogs safer and more manageable. So how would Stone Age people have controlled wolves during generations of breeding?
Finally, our alleged wolf-breeders didn’t know about dogs. None had ever existed, so they didn’t know they could create an obedient, super-friendly, manageable wolf-thing. It’s hard then to imagine Stone Age hunter-gatherers putting a lot of energy into a difficult, time-consuming, dangerous breeding project.
Did Wolves Adopt Us?
The newer thinking says natural selection domesticated the dog, with little or no human management.
Once in a while, a lone wolf would follow people around from camp to camp, scavenging their leftovers. The humans might even feed the wolf, if it had the brains not to threaten them. And since wolves are natural pack-hunters, this camp wolf could easily figure out how to help the hunters track and kill prey, making it even more popular. Wolves hunt and socialize a lot like people, so the wolf wouldn’t have too much trouble fitting in.
The camp wolf probably didn’t depend entirely on Homo sapiens. It probably hunted small game on its own too. That’s how dingoes often live in Australia, or used to. The dingo is a subspecies or type of wolf, and some live alongside Aboriginal hunters, both hunting on their own and helping the humans. In other words, these dingoes live wild and free but still share their lives with people.
How did one camp wolf become many? The first lone wolf could easily have arrived pregnant. A pack’s alpha female will drive away any other female who dares to mate. So pregnant females often become lone wolves. Or another lone wolf might join the human “pack,” providing a mate.
Natural Selection for Courage around Humans
Among these camp wolves, the animals least afraid of humans got the best treatment. In particular, they got first dibs at the humans’ meat. So these less fearful wolves ate more, survived longer, and had more pups.
That’s natural selection — for low fear of humans. Over the generations, or centuries, selection for that trait led to a cascade of other changes in the camp wolves. Those include shorter noses, curled tales, floppy ears, patches of white fur, puppy-like playfulness, and a tendency to bark when excited — not to mention a submissive, tail-wagging love for Homo sapiens. In other words, the camp wolves became dogs. Why? What’s the connection between those features and low fear of humans? Scientists think the hormone that reduces avoidance and fear also triggers all those doggy traits.
And that’s not just speculation. We’ve actually seen selection for low fear of humans lead to dog-like features in a similar species.
What Russian Foxes Tell Us about Dog Domestication
In 1959, Russian scientists in Siberia began a multi-decade experiment with foxes. From a group of animals kept for fur, researchers bred the foxes least afraid of people. After ten generations of this breeding, the experiment had transformed a fifth of the foxes. They had shorter noses, curled tails, floppier ears, white patches, and puppy-like playfulness — and they’d become submissive tail-waggers who love, love, love human beings.
In other words, selection for low fear of humans created a new dog-like creature. In fact, you can adopt one of these Russian foxes, and they make great pets — unlike all other foxes.
Dog Domestication Reloaded
We don’t know how many times dogs were domesticated. It’s possible the camp wolf story above happened only once, and all dogs descend from that first camp wolf. Or the story may have played out over and over in different places and times.
Humans certainly do manage dog mating now and have for centuries, creating today’s many breeds. (There’s no way natural selection created animals that can hardly breathe, like the English bulldog, or animals with hair blocking their eyes, like the Tibetan terrier.) But most likely no one bred the dog in the first place. Rather, camp wolves evolved into dogs, thanks to life with humans.
- Grey wolf in Bavarian Forest National Park, courtesy of MrT HK, licensed under Creative Commons Attribution 2.0 Generic (CC BY 2.0)
- Among cannibals; an account of four years’ travels in Australia and of camp life with the aborigines of Queensland, Lumholtz and Rasmus, cropped and color-adjusted, courtesy of Wikimedia Commons
- A Russian domesticated Red Fox with “Georgian White” fur color, by Kayfedewa, licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0).
For a great book on the subject, see Pierotti and Fogg, The First Domestication: How Wolves and Humans Coevolved, Yale University Press (November 28, 2017).
This post updates a prior one, Were We Just Bystanders in Dog Domestiction?
© 2020 by David W. Tollen
The theory that dogs domesticated themselves out of opportunism makes a lot of sense to me. I loved this article.