OXFORD, England — Before humans milked cows, herded goats or raised hogs, before they invented agriculture or written language, before they had permanent homes, and most certainly before they had cats, they had dogs.
Or dogs had them, depending on how you view the human-canine arrangement. But scientists are still debating exactly when and where the ancient bond originated. And a large new study being run out of the University of Oxford here, with collaborators around the world, may soon provide some answers.
Scientists have come up with a broad picture of the origins of dogs. First off, researchers agree that they evolved from ancient wolves. Scientists once thought that some visionary hunter-gatherer nabbed a wolf puppy from its den one day and started raising tamer and tamer wolves, taking the first steps on the long road to leashes and flea collars. This is oversimplified, of course, but the essence of the idea is that people actively bred wolves to become dogs just the way they now breed dogs to be tiny or large, or to herd sheep.
The prevailing scientific opinion now, however, is that this origin story does not pass muster. Wolves are hard to tame, even as puppies, and many researchers find it much more plausible that dogs, in effect, invented themselves.
How did it start?
Imagine that some ancient wolves were slightly less timid around nomadic hunters and scavenged regularly from their kills and camps, and gradually evolved to become tamer and tamer, producing lots of offspring because of the relatively easy pickings. At some point, they became the tail-wagging beggar now celebrated as man’s best friend.
Some researchers question whether dogs experience feelings like love and loyalty, or whether their winning ways are just a matter of instincts that evolved because being a hanger-on is an easier way to make a living than running down elk. Raymond Coppinger, a professor emeritus of biology at Hampshire College, noted in his landmark 2001 book, “Dogs,” that “best friend” is not an “ecological definition.” And he suggested that “the domestic house dog may have evolved into a parasite.”
Researchers also point out that of the estimated 1 billion dogs in the world, only a quarter of them are pets. The vast majority of dogs run free in villages, scavenge food at dumps, cadge the odd handout and cause tens of thousands of human deaths each year from rabies. They are sometimes friendly, but not really friends.
Modern dogs are different from modern wolves in numerous ways. They eat comfortably in the presence of people, whereas wolves do not. Their skulls are wider and snouts shorter. They do not live in pack structures when they are on their own, and so some scientists scoff at dog-training approaches that require the human to act as pack leader.
Wolves mate for the long haul and wolf dads help with the young, while dogs are completely promiscuous and the males pay no attention to their offspring. Still, dogs and wolves interbreed easily and some scientists are not convinced that the two are even different species, a skepticism that reflects broader debates in science about how to define a species, and how much the category is a fact of nature as opposed to an arbitrary line drawn by humans.
Tracing the origins
If current divisions between species are murky, the past lies in deep darkness. Scientists generally agree that there is good evidence that dogs were domesticated around 15,000 years ago. By 14,000 years ago, people were burying dogs, sometimes along with humans. But some biologists argue, based on DNA evidence and the shape of ancient skulls, that dog domestication occurred well over 30,000 years ago.
And as to where the process occurred, researchers studying dog and wolf DNA — most of it modern but some from ancient sources — have argued in recent years that dogs originated in East Asia, Mongolia, Siberia, Europe and Africa.
One reason for the conflicting theories, according to Greger Larson, a biologist in the archaeology department at the University of Oxford, is that dog genetics are a mess. In an interview at his office here in November, he noted that most dog breeds were invented in the 19th century during a period of dog obsession that he called “the giant whirlwind blender of the European crazy Victorian dog-breeding frenzy.”
That blender, as well as random breeding by dogs themselves, and interbreeding with wolves at different times over at least the last 15,000 years, created a “tomato soup” of dog genetics, for which the ingredients are very hard to identify, Dr. Larson said.
Building a database
The way to find the recipe, Dr. Larson is convinced, is to create a large database of ancient DNA to add to the soup of modern canine genetics. And with a colleague, Keith Dobney at the University of Aberdeen, he has persuaded the Who’s Who of dog researchers to join a broad project, with about $2.5 million in funding from the Natural Environment Research Council in England and the European Research Council, to analyze ancient bones and their DNA.
Robert Wayne, an evolutionary biologist at UCLA who studies the origin of dogs and is part of the research, said, “There’s hardly a person working in canine genetics that’s not working on that project.”
That is something of a triumph, given the many competing theories in this field. “Almost every group has a different origination hypothesis,” he said.
But Dr. Larson has sold them all on the simple notion that the more data they have, the more cooperative the effort is, the better the answers are going to be. His personality has been crucial to promoting the team effort, said Dr. Wayne, who described Dr. Larson as “very outgoing, gregarious.” Also, Dr. Wayne added, “He has managed not to alienate anyone.”
Scientists at museums and universities who are part of the project are opening up their collections.
If all goes well, Dr. Larson said, the project will publish a flagship paper from all of the participants describing their general findings. And over the next couple of years, researchers, all using the common data, will continue to publish separate findings.