According to new mathematical models, dogs could have domesticated themselves via bonding with humans while scavenging for food at Paleolithic settlements starting around 30,000 years ago.
Paras Kaushal/UnsplashUnder the right conditions, wolves could have domesticated themselves into dogs over the course of about 8,000 years via bonding with Paleolithic humans.
For thousands of years, dogs have been man’s best friend. When humans still lived primarily in hunter-gatherer societies, dogs were among the first domesticated animals. And as the millennia passed, the relationship between man and dog has remained, in many ways, unchanged.
But there has long been debate in the scientific community about when and how, exactly, wolves were domesticated into dogs. Some have speculated that, much like today, humans aided in the process, selectively breeding wolves for tamer traits and other desired features. Humans needed wolves for the hunt, and in return supplied wolves with a portion of the meat, or so the theory goes.
However, a new set of mathematical models published in Proceedings of the Royal Society: Biological Sciences is proposing a different theory: wolves “self-domesticated” into dogs to reap the benefits of human food scraps.
It’s not an altogether new concept, but the new models could help to clarify the timeline somewhat, showing how natural selection could have turned wild wolves into domesticated dogs over the course of a few thousand years — all without selective breeding by humans.
How Were Dogs Domesticated? The Debate Surrounding How Modern Canines Evolved From Wolves
Wikimedia CommonsA North American gray wolf, a close descendant of the gray wolves that kickstarted the domestication of dogs.
It has been well established that humans and dogs have had a strong domestic bond for at least 30,000 years. Archaeological and genetic evidence also shows that dogs are descended from gray wolves and that they became domesticated over the course of two distinct historical periods.
The first domestication period took place between roughly 30,000 and 15,000 years ago, during which wild wolves were domesticated into early dogs. The second period, from 15,000 years ago to the present day, saw the emergence of a variety of dog breeds, some resulting from selective breeding by humans.
Public DomainA watercolor tracing by archaeologist Henri Breuli of a cave painting depicting a wolf-like canid, dated to 19,000 years ago.
Some members of the scientific community have previously argued that the first domestication period was also heavily influenced by humans and selective breeding that was done to tame wild wolves. There are several reasons for this argument, but the main two are: natural selection would not have worked quickly enough to domesticate dogs in that period of time, and it’s more likely that wild wolves would have seen ancient humans as competitors for food and not partners.
“I don’t think it is a likely scenario that ancient hunters would have worked alongside predators who would be at best more likely to view them as competitors than partners of any kind,” Kathryn Lord, an evolutionary biologist at the University of Massachusetts Chan Medical School in Worchester, who was not involved in the study, told National Geographic.
Wikimedia CommonsAn ancient petroglyph depicting a Hawaiian Poi Dog.
Perhaps, some have suggested, ancient humans inadvertently created a population of tamer wolves when they took some in as pups and raised them in human communities. Or, maybe our ancestors recognized the potential of canine hunting companions and kicked off the process on purpose.
The other side of the debate, meanwhile, suggests that wolves initiated the domestication process themselves.
Drawn to discarded food scraps left at ancient human settlements, certain groups of wild wolves acted as scavengers, setting aside their aggression in exchange for easy meals. These tamer wolves would have naturally isolated themselves from more aggressive packs and mated with wolves of the same tameness, thus resulting in a self-domestication process that took place over thousands of years.
But could this process of natural selection really have occurred over such a short (in evolutionary terms) period of time? According to the new models, it’s certainly possible.
How New Mathematical Models Support The Theory That Dogs Domesticated Themselves
Wikimedia CommonsA pack of wolves pursuing an elk.
Without human intervention to speed up the domestication process, critics have argued, it would take far too long for wolves to have self-selected the genetic traits that eventually led to speciation — the formation of a new, separate dog species — over the given timeline. Up until now, though, no one had actually tried to apply mathematical modeling.
“I don’t think mathematical models have really shown up in this discussion yet,” said mathematical ecologist and study author David Elzinga. “I think they have a lot to contribute.”
The researchers ran several models, including ones where tamer, scavenging wolves mated solely with each other and models where they mated with other, more aggressive wolves. Across the models, early dogs separated from wolves 37 percent of the time. If scavenging animals mated with other tamer animals, however, they formed early dog packs 74 percent of the time.
Wikimedia CommonsA modern wolf carrying a caribou hindquarter.
“When females were selecting mates, they also had to select males that had a similar tameness to themselves,” study co-author Alex Capaldi told Live Science. “So if both of those processes are in play, then it is possible for the self-domestication hypothesis to beat the time constraint critique.”
In this latter scenario, it took about 8,000 years for dogs to separate from wolves, and that change, in the model, lasted more than 3,400 years, until the model ran out of “time.”
While the model doesn’t outright prove the self-domestication theory or provide a definitive answer as to how dogs became domesticated, it does at least prove that, under the right circumstances, self-domestication was at least possible.
Of course, it’s also likely that the answer isn’t quite so black and white. Given how close humans and dogs have been historically, the answer is probably some combination of both human influence and dogs choosing to be around them. At the very least, it doesn’t seem as if humans forced domestication onto dogs.
“There are lots of process that are going on,” Capaldi said. “It’s probably a question of, not which one was it, but which one was the larger factor.”
After learning about how dogs may have domesticated themselves, learn about how humans once tried to domesticate the cassowary — the most dangerous bird in the world. Then, read about some of history’s most famous dogs.
