New archaeological research is reshaping our understanding of when domestic dogs first developed the wide range of shapes and sizes seen today. The study shows that dogs began to vary in form far earlier than scientists once believed, with clear signs of diversity appearing at least 11,000 years ago.

Using advanced shape analysis on hundreds of ancient remains collected across tens of thousands of years, researchers were able to track how early dogs changed over time. Their findings pinpoint a deep prehistoric moment when dogs started to differ noticeably in both size and skull shape.

Dog Diversity Predates Modern Breeding by Millennia

For decades, many scientists assumed that most dog diversity resulted from recent selective breeding practices that emerged with Victorian Kennel Clubs. This new work challenges that idea. Instead, it reveals that dogs were already showing substantial physical variation thousands of years ago, not long after they split from wolves.

The results suggest that early dogs were adapting quickly, long before the appearance of modern breeds, driven by their close and growing relationship with human communities.

A Global Study Spanning 50,000 Years

Published in Science and led by researchers at the University of Exeter and the French CNRS, the project is the most wide-ranging analysis of dog skulls ever conducted. The study began in 2014 and examined 643 canid skulls from both modern and archaeological sources, including recognized breeds, street dogs, and wolves. Together, these specimens span roughly 50,000 years, from the Pleistocene to the present.

Scientists from more than 40 institutions worked together to create detailed 3D models of each skull. They analyzed these models using geometric morphometrics, a method that allows precise comparisons of size and shape.

Early Dogs Took on Many Roles and Forms

The analysis revealed that by the Mesolithic and Neolithic periods, dogs already displayed a broad range of skull shapes and body sizes. This growing diversity likely reflected the many roles dogs played in early human societies, including hunting, herding, guarding, and companionship.

"These results highlight the deep history of our relationship with dogs," said co-lead author Dr. Carly Ameen of Exeter's Department of Archaeology and History. "Diversity among dogs isn't just a product of Victorian breeders, but instead a legacy of thousands of years of coevolution with human societies."

The Earliest Known Domestic Dogs

The oldest confirmed domestic dog in the study came from the Russian Mesolithic site of Veretye (dating to ~11,000 years ago). Researchers also identified early domestic dogs in America (~8,500 years ago) and Asia (~7,500 years ago), based on skull shapes associated with domestication. After these early appearances, variation among dogs increased rapidly.