Humans and Dogs Have Been Friends for More Than 15,000 Years, New Study Finds

We all know that dogs are humankind’s best friend — but now we know it's been for far longer than we originally thought.

Two new studies, both published on Wednesday in the journal Nature, revealed the first definitive genetic evidence that dogs and humans were living alongside one another dates as far back as 15,800 years ago. To put it in perspective, that’s before humans started farming. 

The scientists looked at canine specimens from five different archaeological sites across Europe and Western Asia. The oldest dog — the one that they were able to determine was 15,800 years old — was found in Anatolia, Turkey and buried alongside a human companion. The second-oldest came from a cave in Somerset. This one was 14,300 years old. 

“This means that by 15,000 years ago, dogs with very different ancestries already existed across Eurasia, from Somerset to Siberia,” Dr. Lachie Scarsbrook, one of the co-first authors of the study, told The Guardian. “This raises the possibility that domestication occurred during the last ice age, more than 10,000 years before the appearance of any other domestic plants or animals.”

Previous evidence put the domestication of dogs from grey wolves roughly before the end of the last ice age, about 12,000 years ago. But the oldest genetic evidence was only from 10,900 years ago. This was because lots of times DNA from very old bones ends up too fragmented to analyze in depth, especially when it comes to differentiating between dogs and wolves. So pinpointing the exact moment that dogs became their own separate species was very tricky.

“For a long time the only way we could tell whether something was a dog or wolf was to look at the bones, which is not necessarily so reliable,” Dr. Anders Bergström, one of the other authors, said to the Guardian. “Someone would say: ‘It’s a dog’ and another person would say: ‘No, it’s a small wolf.’”

The bones came from sites associated with three distinct hunter-gather cultures. What was particularly interesting is that across the five sites, the dogs were more genetically similar. This suggests that early human societies were exchanging dogs or acquiring them from each other in some way. 

“The people are so different, but the dogs are very much the same,” Greger Larson, another author on the studies, said to The New York Times. “It is kind of the equivalent of a new blade or a new point or a new kind of material culture or art form or something, where everybody’s getting really excited about having this fun new thing around. And it’s useful and it’s interesting and it’s probably cute.”

The researchers are still unsure just how dogs fit into these different societies. Given how much human cultures and environments ranged from region to region, it’s likely that the dogs had different roles in different places. 

One thing was clear: all the societies appeared to have close relationships with their dogs. There was evidence that the early humans provided their dogs with food and treated their bodies with reverence in death. At one site, the bones of three puppies were found over the legs of a human, which mimics the burial practices given to humans. 

“I think it's also interesting that, unlike most other domesticated animals, dogs do not always have very clearly defined roles or purposes for humans. Perhaps their primary role is often ​just to provide companionship,” Bergström said to Reuters.