Dogs 10,000 years ago were already more diverse than we can imagine. understand

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“About 10,000 years ago, half of all the variation we see today was already present in dog populations,” said Kari Ameen, a bioarchaeologist at the University of Exeter and one of the lead authors of the study published Thursday in the journal Science. “This really challenges our ideas about the origins of dog diversity and the common theory that it was created in the Victorian era.”

The first dogs were already diverse

Exactly when, where, and how wild wolves gave rise to domestic dogs still sparks intense scientific debate. In the new study, an international team led by Ameen and Arowen Evin, a bioarchaeologist at the University of Montpellier, analyzed more than 600 skulls from members of the canid family, including dogs and wolves.

More than 150 of these skulls belonged to modern dogs, including purebreds, mongrels, and feral dogs, and another 86 belonged to modern wolves. The rest were archaeological specimens collected at archaeological sites around the world from canids that lived during the past 50,000 years.

The researchers divided these specimens into two categories. One is from a canid that lived during the Late Pleistocene, more than 12,700 years ago, and the newest specimen is from an animal that was already in the Holocene, less than 11,700 years old.

In general, scientists observed that the skulls of older wolves and canids were longer and narrower, and on average slightly larger, than modern dogs and recent specimens.

Formatting lost over time

Holocene dog and canid skulls were more diverse in size and shape than wolf skulls, including some that were significantly shorter and wider. “You can see a much more robust and compact skull shape,” Ameen said. Some extreme features, such as the nearly flat nose of modern dog breeds (such as pugs), appear only in modern dogs and have no similarities in archaeological specimens.

The researchers also identified a skull shape in the new specimen that is not seen in modern dogs. Amin said the reason for this disappearance is unknown, but one hypothesis is that certain body types lost their functionality or attractiveness over time. “Perhaps there was a role or profile for dogs that we don’t value today as much as we used to,” he says.

The study also found that the oldest skulls with distinctly canine features date back to around 11,000 years ago. Previous specimens, including one that had already been proposed to be a primitive dog, did not display typical characteristics of domestic animals.

“There’s been a lot of debate about these very ancient canids, especially canids that are more than 15,000 years old,” says Melanie Fillios, an anthropoarchaeologist at the University of New England in Australia who was not involved in the study. “Was it a primitive dog?” She says the new analysis suggests these “question mark-shaped” specimens are much more similar to wolves than dogs.

The factors that led to the diversity of dogs in the first place are not yet clear, but experts point to a combination of factors. The ancestors of wolves were relatively diverse, and coexistence with humans may have made it possible for canids with characteristics that would not survive in the wild. “Chihuahuas don’t make good wolves, do they?” Ameen joked. “Domestication allows these forms to survive.”

The variety of dogs may have also expanded due to environment, diet, and adaptation to new areas. The increase in diversity coincides with periods of intense human migration. “We’re seeing massive movements of people around the world,” Fillios said. “And dogs are part of that story.”

A new study, also published this Thursday in the journal Science, strengthens this connection by showing that ancestral dogs often accompanied humans on their journeys, and some societies may even have traded these animals. “Eurasian dogs have lived and migrated with humans of different civilizations and lifestyles, including hunter-gatherers, farmers, and nomads,” Guo Dong Wang, a researcher at China’s Kunming Zoological Research Institute and one of the second study authors, said in an email. “These groups adopted different breeding strategies for their dogs, depending on their survival and production needs.”