Dogs began developing into different shapes and sizes much earlier than previously believed, according to groundbreaking new research from the University of Exeter that challenges long-standing assumptions about canine evolution.
Ancient Origins of Canine Diversity
Scientists at the University of Exeter have analysed 643 modern and archaeological canine specimens spanning the last 50,000 years, including recognised breeds, street dogs, and wolves. Their findings pinpoint the surprising moment when dogs began to physically diversify – around 11,000 years ago, during the Mesolithic and Neolithic periods.
The research, conducted in collaboration with French colleagues, used 3D models of skulls to study size and shape variations. Results showed that early dogs already displayed about half of the total cranial variation observed in modern dogs today.
Challenging Victorian Assumptions
These findings directly challenge the long-standing assumption that dogs only look different because of selective breeding since the Victorian era. While researchers acknowledge that Victorians were largely responsible for what we now recognise as formal breeds, the study demonstrates that physical diversity in dogs dates back thousands of years earlier than commonly thought.
'These results highlight the deep history of our relationship with dogs,' said study 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.'
Timeline of Canine Evolution
The earliest specimen identified as a domestic dog came from the Russian Mesolithic site of Veretye dating to approximately 11,000 years ago. The team also identified early dogs from America around 8,500 years ago and Asia about 7,500 years ago with distinctive 'domestic skull shapes' – proportionally shorter and wider compared with wolves.
According to study author Dr Allowen Evin at CNRS in France, while early dogs didn't show the extreme skull shapes of modern breeds like pugs or bull terriers, 'Mesolithic and Neolithic dogs already displayed about half of the total cranial variation observed in modern dogs. This means that early dogs varied considerably in skull size and proportions.'
The research, published in the journal Science, reveals several key milestones in canine evolution:
- 11,000 years ago: Dogs begin to diversify in size and shape
- 9,700-8,700 years ago: Overall reduction in dog skull size
- From 8,200 years ago: Greater variability in skull shape
- From 7,700 years ago: Increase in canine size variability
Dr Evin emphasised that modern breeds now range from chihuahuas to mastiffs and from flat-faced pugs to long-snouted greyhounds – forms far more extreme than anything found in the archaeological record.
Dr Dan O'Neill, professor of animal epidemiology at Royal Veterinary College who was not involved with the study, agreed that diversity of the canine body as an overall concept has been around for thousands of years. However, he stressed that selective breeding of extreme and unhealthy body shapes is a much more recent phenomenon, dating back to about the late 1800s.
'What did happen in Victorian England was the invention of breed as a concept in dogs and the formal written descriptions of what a breed should look like,' Dr O'Neill told the Daily Mail. 'This was for the purposes of having a standard to compare between dogs in a show ring. This built on the thousands of years of physical diversity to create all these new breeds that emerged around then in the late 1800s.'
The study focused exclusively on skull morphology rather than other physical traits like coat colour or body size, but researchers confidently identified when cranial features diverged from the wolf pattern to form what we recognise as a 'domestic' shape today.
