They may be man’s best friend, but could we have created dogs in our own image? Scientists say that by selectively breeding the animals for certain behaviours, humans have shaped their brains.

Over several hundred years, people have bred different lineages of domestic dogs for different tasks – such as hunting, herding, guarding or companionship. 

A study published in the JNeurosci, the Journal of Neuroscience, examined whether and how selective breeding has altered the organisation of the brain in dogs.

Erin Hecht, from the department of human evolutionary biology at Harvard University, and colleagues analysed magnetic resonance imaging (MRI) scans of 62 male and female dogs of 33 breeds.

The research team observed a wide variation in brain structure that was not simply related to body size or head shape. Scientists examined the areas of the brain with the most variation across breeds, which included beagles, dachshunds, greyhounds and Labrador retrievers.

This generated maps of six brain networks, with proposed functions varying from social bonding to movement, that were each associated with at least one behavioural characteristic.

The variation in behaviours across breeds was correlated with anatomical variation in the six brain networks, researchers say.

Importantly, an analysis looking at evolutionary relationships revealed the majority of changes between breeds occurred relatively recently.

Researchers say these results establish that the significant variation in brain anatomy in dogs is likely due to human-applied selection for behaviour.

“These results indicate that through selective breeding, humans have significantly altered the brains of different lineages of domestic dogs in different ways,” the authors wrote. 

“Finally, on a philosophical level, these results tell us something fundamental about our own place in the larger animal kingdom – we have been systematically shaping the brains of another species.”