Bones of 15,800-year-old puppy push confirmed origin of our canine companions back nearly 5000 years
In the summer of 2004, Douglas Baird was leading excavations at a remote hunter-gatherer site called Pınarbaşı in central Turkey when his team found something unusual: three puppies placed in a pit directly above a human burial. The bones were too small to tell whether they belonged to wolves or dogs. Their proximity to the human suggested the latter, but the remains—dated to about 15,800 years ago—were nearly 5000 years older than any confirmed dog. “Our minds were racing,” says Baird, an archaeologist at the University of Liverpool.
Now, more than 2 decades later, ancient DNA analysis of the bones confirms the pups were indeed dogs, researchers report today in Nature. The study, along with a second paper in Nature, also provides new insight into how dogs spread throughout Europe—and how they may have interacted with ancient humans.
It’s a “supercool” finding, says Natalie Munro, an archaeozoologist at the University of Connecticut who was not involved with either study. “It’s very, very important to have data from this time period. Without it, we can’t talk about the deep history of dogs.”
Despite decades of study, dogs remain one of the greatest mysteries in archaeology. Scientists know they descend from gray wolves, but exactly when this happened—and whether it happened more than once—has been unclear. Until now, the oldest genetically confirmed dog was an 11,000-year-old canine found at a site in northwestern Russia. Archaeologists have unearthed much older suspected dogs—animals whose shorter and wider skulls, for example, are a hallmark of changes that took place as wolves became domesticated. But until now, they did not have the detailed genetic information needed to close the case.
14,200-year-old dog jawbone from the Kesslerloch cave in northern Switzerland suggests dogs were widespread across Europe during this time
In the new studies, researchers sequenced the nuclear DNA (which makes up the majority of an animal’s genome) of one of the Pınarbaşı pups, as well as of suspected dogs at Gough’s Cave in southern England and a cave known as Kesslerloch in northern Switzerland. Those sites date to about 14,300 and 14,200 years ago, respectively.
Many putative ancient dogs have turned out to be wolves after genetic testing was done, but that wasn’t the case with the Pınarbaşı pup. “It’s 100% a dog,” says Lachie Scarsbrook, a paleogeneticist at the Ludwig Maximilian University of Munich who—along with paleogeneticist William Marsh at the Natural History Museum in London—led the analysis of the Pınarbaşı and Gough’s Cave specimens. “There’s no trace of wolfiness.”
The Gough’s Cave and Kesslerloch animals also turned out to be dogs, and their mitochondrial DNA (a much smaller component of an animal’s genome inherited from mothers) was a close match to that of 14,000-year-old canine remains from western Germany and southern Italy, revealing that dogs were widespread across Europe by this time.
The genomes of the Turkish, English, and Swiss dogs were strikingly similar to one another, despite the vast geographical distances separating the sites, and the very different human cultures there. People at Gough’s Cave, for example, were part of the Magdalenian culture—renowned for its sophisticated cave paintings (and, in the case of the Gough’s Cave inhabitants, making cups from human skulls). Pınarbaşı, meanwhile, was home to Anatolian hunter-gatherers, direct ancestors of the farmers who introduced agriculture to Europe. Humans from these disparate cultures had genetic differences, “but we don’t see the same pattern in dogs,” Marsh says. “They must have all come from the same population.”
Indeed, they may represent Europe’s ur-dogs, an ancient lineage that had yet to become specialized, says Greger Larson, an evolutionary biologist at the University of Oxford and co-author on both studies. Whereas later dogs were bred to perform a wide variety of tasks—perhaps as co-hunters and protectors—these early dogs were more of a “Swiss Army knife,” Larson says. “It’s almost as if this is a new, supercool thing that everyone wants.”
Based on canine and human DNA at the various sites, the team suggests Epigravettian people, expert stone-tool craftsmen who lived throughout southern and eastern Europe between about 21,000 and 12,000 years ago, may have helped spread dogs throughout the continent. “All of a sudden, this animal arrives that you’ve never seen before,” says Scarsbrook, who speculates that these ancient dogs may have been smaller and differently colored from wolves. “To witness people who have harnessed your biggest competitor—that must have been a day.”
A similar scenario may have unfolded again, thousands of years later, as early farmers migrated into Europe, bringing their own dogs. These human newcomers almost totally replaced earlier Europeans. But European dogs lived on. By analyzing dog remains dated to between about 9000 and 7000 years ago—spanning the time before and after the arrival of agriculture in Europe—the second Nature study finds that only about 50% of European dog DNA was replaced by Near Eastern DNA, indicating the migrating farmers may have found the European dogs especially useful. “They seem to incorporate these dogs rather than trying to replace them with their own,” says Anders Bergström, a geneticist at the University of East Anglia who led the work as well as the analysis of the Kesslerloch specimen. (The opposite happened in North America, where colonizing Europeans seem to have wiped out the indigenous dogs.) Perhaps European dogs were more suited to guarding or hauling than the Near Eastern dogs, he says, or maybe they just made better companions.
Neither study answers the age-old question of where dogs ultimately came from, though Bergström’s work challenges the idea that they arose in multiple locations, perhaps in both Europe and Asia. He and his colleagues found that the Kesslerloch dog—and, by extension, the other ancient dogs in the two papers—shares DNA with modern dogs all over the world, suggesting they have a common origin. “There is no need to propose an independent domestication,” Bergström says. “Though we can never rule it out.”
A few years after his team discovered the Pınarbaşı pups, Baird—a co-author on both new studies—made a similar find at a nearby site known as Boncuklu Höyük, occupied a few thousand years later. But there was a twist. Instead of being buried near humans, the dogs here were buried with them, suggesting a deepening of the human-dog relationship over time. Additional finds should further illuminate that growing bond between our two species. “The story,” Baird says, “continues.”