In the past few decades, research into dog domestication has generated intense interest in the scientific community. Experts debate both the definition of “domestication” and the precise origins of the domestic dog. “Disagreements have emerged because it’s hard to tell a dog from a wolf if all you have are bony remains, so pinpointing when some wolves evolved into dogs and what role humans may have played in that evolution is no easy feat,” says the paleoanthropologist Pat Shipman, a former professor at Penn State University who was not involved with the study.

A new origin story for dogs

Recent studies have tried to find evidence of domestication by identifying changes in the genes and skeletal morphologies, or bone structures, of ancient animals. These analyses have helped us get a clearer idea of when and where dogs emerged more than 15,000 years ago. But researchers have seldom looked at how and why dogs and humans interacted. A diversity of cultural practices may have shaped these relationships, but until now they have rarely been investigated.

Understanding how humans and canines lived together is important because specific human practices and mutual cooperation between species may explain changes in the physical aspect and behaviors of dogs. “By documenting the interactions between one group of dogs and one group of humans at Ust’-Polui, long after the first encounter between the species is thought to have happened, we wanted to show there is more to domestication than bodily changes,” Losey says.

To gain insight into human-dog interactions, the researchers retraced the life stories of some of the animals that had lived at Ust’-Polui around 2,000 years ago by looking for evidence of how they were treated and what activities they participated in. They also analyzed the shapes of the bones and crania to find out more about the body structures, health, and ages of the dogs.

In the four centuries that Ust’-Polui was occupied, hundreds of dogs may have passed through the site, according to the research team. Many fragmented bones, Losey and his colleagues found, belonged to young dogs, with some of the remains bearing cut marks. The researchers suggest that humans at Ust’-Polui killed and likely ate these animals.

It seems the ancient communities at Ust’-Polui gave special attention to dog crania, which are unusually abundant at the site, according to the team. These crania, as well as some of the animals’ mandibles, were attached to sticks or straps as ornaments, and some are thought to have been worn by people. The dogs that these remains belonged to may have been ritually sacrificed. In addition, some of the animals were buried whole after what appears to have been a natural death.

Losey and his colleagues had previously analyzed the chemical composition of the bones to try to determine the diet of the dogs buried at the site. A number, they discovered, had consumed fish from nearby rivers, suggesting that they were possibly dependent on humans for some of their basic needs. The scientists also found the remains of wooden sleds that were likely pulled by the animals. Sled pulling, the researchers believe, may have taken a toll on the dogs’ bodies and transformed them over time. In the long term, their bone structure may have adapted to better bear the strains of sled pulling.