Dogs typically have smaller brains than wolves. But new research shows that the gap between the two is slowly closing as modern dog breeds now have larger brains compared to their ancestors.
The research, titled "Evolution of Relative Brain Size in Dogs-No Effects of Selection for Breed Function, Litter Size, or Longevity" published in the journal Evolution, reports that modern dogs have slightly larger brains compared to their body size due to selective breeding efforts. This increase in brain size is believed to be influenced by the complex interactions between dogs and humans.
Modern Dog Breeding Efforts Triggered Cognitive Growth in the Past 150 Years
Previous studies have consistently shown that the domestication of various animals, including dogs, leads to a reduction in their relative brain size. This is believed to be a result of the decreased need for advanced cognitive abilities in domesticated animals for survival. However, a surprising discovery was made when comparing the skulls of 159 dog breeds, including wolves.
Although wolves have brains that are 24% larger than similarly sized domesticated dogs, Science Alert reported that the research revealed that the more genetically distinct a dog breed was from wolves, the larger their brain size.
This suggests that while domestication of dogs in ancient times may have initially led to a decrease in certain areas of the brain associated with traits like mate choice, predator awareness, or hunting, modern breeding practices have contributed to a modest increase in cognitive growth over the past 150 years.
Niclas Kolm, an evolutionary biologist from Stockholm University in Sweden, explained in a news release that different dog breeds vary in social complexity and perform complex tasks that most likely need a larger brain capacity.
Proving Social Brain Hypothesis
As per Science Alert, Kolm and his team expected that dog breeds bred for complex tasks like herding or sports would have larger brain sizes to test their hypothesis.
However, their research showed that the relative brain size of modern dog breeds was influenced solely by the genetic differences between the breeds and wolves, not their specific functions, litter sizes, or life expectancies. Interestingly, no difference in relative brain size was found among the breeds recognized by the American Kennel Club.
Previous studies have indicated that the absolute brain size of individual dogs can affect their memory and self-control. However, this factor does not seem to strongly influence the overall relative brain size of dog breeds. The findings align with other recent research suggesting that the behavioral traits associated with specific dog breeds are not clearly reflected in their genetic makeup.
Ethologist Enikő Kubinyi from Eötvös Loránd University in Hungary speculates that the increase in relative brain size in modern dog breeds may be attributed to factors such as a more complex social environment, urbanization, and adaptation to greater societal rules and expectations.
This supports the social brain hypothesis, which suggests that larger brains can evolve to meet the demands of more intricate social environments.
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