How were dogs domesticated?
It’s certainly easy to explain the close relationship between humans and domesticated dogs as a human-sought endeavor, especially when that furry friend sitting at your feet doesn’t do much in return for being fed and cared for, besides the occasional nuzzle and tail wag.
But was domesticating dogs done with a purely human-driven, top-down approach? A new essay in National Geographic by Dr. Brian Hare, director of the Duke Canine Cognition Center and Vanessa Woods, a Duke research scientist, suggests it might have been the other way around.
The common belief is that dogs were domesticated by humans, as people took on the friendliest and most docile of wolf cubs, and bred the animals to be even more docile. These tame wolves ate our garbage and their barking served as an early warning system for nighttime dangers. Over time, these tame wolves became tamer, grew smaller and developed smaller snouts. And in Victorian times, breeding took off in Europe, leading to the enormous amounts of different breeds.
But Hare and Woods claim this top-down view might not be true, and point to our historic relationship with other carnivorous mammals. It turns out, prehistoric humans didn’t get along with their carnivorous competition at all. When early humans expanded to Europe 43,000 years ago, they wiped out almost all the large carnivores on the continent, including giant hyenas and saber-toothed cats. It’s unclear whether these predators died because of human hunting or from competition with people, but as Hare and Woods put it, “most of the Ice Age bestiary went extinct.” The hypothesis that wolves helped humans hunt doesn’t hold up either. Humans were already the most successful hunters (just ask the sabre-toothed cats) without the help of some friendly wolves, and as we’ve seen on nature documentaries, wolves eat a lot (a deer a day for a 10-wolf pack) and do not like to share, making them difficult hunting partners.
Humans did not give up their wariness toward wolves all they way back in prehistoric times. Henry VII ordered the last wolf in England be killed in the 16th century. And Americans had killed all the wolves in the lower 48 states by 1930. So who first approached whom?
Hare and Woods suggest that while scavenging for garbage around human camps, the boldest of the wolves began to approach humans. Obviously, the wolves that were boldly aggressive were killed, but the wolves that were both aggressive and friendly were tolerated. In a way, we selectively bred the wolves for temperament (although this was probably a nice side effect of “killing the snarling carnivore threatening us”).
As populations of friendly wolves began developing around human settlements, other adaptations took hold. The wolves’ coats became splotchy, their ears floppy, and their tails began to wag. This last change in particular went hand in hand with a change in the wolves’ (now protodogs') psychology: they developed the ability to read human gestures, cementing their bond with humans.
Dogs can understand humans remarkably well, even better than our smarter, more closely related cousins, chimpanzees. And it was this that made them valuable hunting companions: understanding commands, pointing gestures and even something as subtle as a change in eye direction.
In the end, the domestication of dogs was not a result of a human benefactor with a soft spot for furry animals. Instead, it came from a partnership first initiated by some bold, but friendly wolves looking for some garbage. And it was their ability to communicate and understand us (that nuzzle and tail wag) that convinced us to keep them around.
The essay is adapted from their new book, The Genius of Dogs and can be found at National Geographic Daily News.
(Edited by Lois Heyman)
