IDogs’ brains are much smaller than those of wolves, but new research suggests that modern breeding methods have increased their size somewhat.
Header image: Belgian Shepherd Tervueren and cub (Bence Járdány/ Loránd-Eötvös University)
Compared to ancient dog breeds, modern breeds that have developed over the past 150 years possess larger skulls relative to their body size. Scientists still don’t know why.
Numerous studies have shown that the domestication of wild animals, such as dogs, fish, pigs, cattle, sheep, rabbits and cats, significantly reduces the relative size of their brains. Scientists believe this is a response to reducing the need for brain capacity for survival. But researchers have discovered something unexpected when comparing the skulls of 159 dog breeds, including some wolves.
While a wolf’s brain is 24% larger than that of a dog of similar size, the more a dog breed differed from a wolf, genetically speaking, the larger its brain. The results suggest that while the domestication of dogs thousands of years ago may have initially shrunk parts of the canine brain (such as those related to mate choice, predators, or hunting), modern breeding has triggered a modest cognitive growth over the past century and a half.
According to Niclas Kolm, an evolutionary biologist at Stockholm University, Sweden:
Different dog breeds live at varying levels of social complexity and perform complex tasks, which likely require greater brain capacity.
Based on the study: CT scan of the skull of a Hungarian short-haired pointer. (Kalman Czeibert)
Kolm and his colleagues therefore hypothesized that some dogs, bred by humans for more complex tasks such as herding or playing sports, would have relatively larger brains… This was not the case. Rather, the only factor that seemed to impact the relative brain size of modern dog breeds was the difference in their genes from those of wolves, not breed function, litter size, or litter size. ‘life expectancy. In fact, researchers could find no difference in relative brain size in the breeds defined by the American Kennel Club.
Previous studies have shown that the absolute size of a dog’s brain plays a role in memory and self-control, but that doesn’t seem to be a strong enough force to influence the relative brain size of the breed as a whole. .
These findings are supported by other recent research, which also suggests that the behavior that some dogs are bred for is not evident in their genetic makeup.
Ethologist Enikő Kubinyi of Eötvös Loránd University, Hungary, speculates that:
The more complex social environment, urbanization, and adaptation to more rules and expectations are perhaps at the root of this change, which affects all modern races.
This hypothesis is consistent with the social brain hypothesis, according to which large brains can evolve to adapt to more complex social environments. Other research, for example, has shown that dogs more closely related to wolves are less good at communicating with humans.
To learn more about the differences between the brains of ancient and modern dogs and those of wolves, the team suggests that future research compare the sizes of different brain regions. They may then be able to determine the impact we have had on the dogs’ brains and behavior.
The study published in the journal Evolution: Evolution of relative brain size in dogs—no effects of selection for breed function, litter size, or longevity and presented on the Loránd-Eötvös University website: The brains of modern dog breeds are larger than those of ancient breeds.
