It is believed that the increase in brain size is a result of increased urbanization and a more complex social environment than their older relatives.
The evolution of modern dog breeds have become genetically more distant from wolves than ever before. A recent study found that today’s dogs have larger brains than those descended from ancient breeds.
In general, domesticated animal’s brains tend to shrink by up to 20 percent as their life becomes simpler. Researchers from Hungary and Sweden hope that by finding out why some dogs’ brains are getting bigger, they might be able to better understand why humans have such large brains compared to their body size.
The norm for domesticated animals is to have brains that shrink.
The brains of domesticated animals can be up to 20 percent smaller than those of their wild ancestors. This is because domestication offers them a safe environment provided by humans and there is no need to fear predator attacks or hunt for food. Therefore, there is no need to sustain the energetically costly large brain, and the freed-up energy can be directed towards other purposes, such as producing more offspring, which is important for domesticated animals. Their lives are simpler.
Why dogs differ from other domesticated animals.
Even today, the known 400 dog breeds have developed relatively quickly and exhibit great diversity, making them a treasure trove for researchers interested in rapid changes within a species.
- The research team found that the increase in brain size cannot be attributed to the roles or life history characteristics of the breeds, suggesting that it is modern living that is driving the growth.
- This is the first comprehensive study regarding the brain size of different dog breeds, and its preparation took several decades.
A senior research fellow at Eötvös Loránd University (ELTE), has been collecting skulls for decades. CT scans of the skulls were performed and based on the images, experts reconstructed the brains and determined their exact volume. In the end, data was gathered from 865 individuals representing 159 dog breeds, with 48 specimens representing wolves and confirmed that domestication has also led to a decrease in brain size in dogs. However, what surprised researchers is that the further a dog breed is genetically distant from wolves, the larger its relative brain size becomes. Some ancient breeds, such as sled dogs, still resemble wolves today. The researchers say that the transition to settlement, agriculture, pastoralism, and the accumulation of wealth offered various tasks for dogs, requiring guard dogs, herding dogs, hunting dogs, and even lap dogs.
Results
The results show that the breeding of modern dog breeds has been accompanied by an increase in brain size compared to ancient breeds.
“We couldn’t explain this based on the tasks or life history characteristics of the breeds, so we can only speculate about the reasons. Perhaps the more complex social environment, urbanization, and adaptation to more rules and expectations have caused this change, affecting all modern breeds.”
These findings are supported by research indicating that ancient breeds known for their independence are less attentive to human cues and bark less, thus exhibiting differences in visual and acoustic communication compared to modern breeds.