Domesticated dogs have smaller brains than wolves, but modern breeds have larger brains than their ancestors thousands of years ago. Living with humans was easier for animals. However, over time it became demanding.
Hundreds of different breeds of dogs, which were created in a short – as for evolution – time, are excellent material for research on how a species can change. Evolutionary scientists are particularly interested in the brain. because in the case of humans it has an unusually large size in relation to the whole body.
A Hungarian team of researchers became interested in the evolution of the canine brain and how it might have been influenced by the tasks that different breeds were designed for. They wondered if, for example, “sofa dogs” have different brains than hunting dogs, and whether brain size is affected by lifespan or the challenges of rearing young?
It is also known for sure that cognitive processes require large amounts of energy, so maintaining a large brain costs a lot.
László Zsolt Garamszegi – the author of a new publication that appeared in the “Evolution” magazine ( – he has been researching the brains of dogs for a long time.
“The brains of domesticated animals can be up to twenty percent smaller than those of their wild ancestors. The likely reason is that the lives of domesticated species are simpler compared to those of their wild counterparts. In a safe environment provided by humans, there are no predator attacks or the need to forage for food. Therefore, there is no need to maintain an energetically expensive, large brain, and the recovered energy can be directed to other purposes, such as reproduction, that are important for domesticated animals” – explains the expert.
Scientists reconstructed the animal brains from scans of the skulls of nearly 700 dogs of 159 breeds and 48 wolves. The collection of these skulls has been accumulated over many decades.
As it turned out, wolves have brains with an average volume of 131 cm3, with an average body weight of 31 kg. In contrast, dogs in a similar weight category have a brain volume of about 100 cm3.
This supports the theory that the domestication of dogs led to their brains getting smaller.
However, this is not the end of the discoveries. Researchers have also noticed that the further a breed is genetically distant from wolves, the larger the brains of its representatives. At the same time, the analysis showed that the destiny of the breed, the number of pups produced and the length of life did not matter in terms of brain size.
“The process of domestication of dogs began about twenty-five thousand years ago, but for ten thousand years dogs and wolves were the same in appearance. Many ancient breeds, such as sled dogs, still resemble today’s wolves,” points out Enikő Kubinyi, co-author of the study. “However, sedentary lifestyles, farming, herding and the accumulation of wealth have created a variety of roles for dogs. There were breeds of guard dogs, shepherd dogs, hunting dogs and even companion dogs. However, a large part of the currently known breeds with a distinctive appearance appeared only after the industrial revolution, mainly in the last two centuries, when dog breeding became a kind of hobby.
However, the exact reasons for the increase in brain volume are unclear.
“We couldn’t explain it based on the race’s quests or history, so we can only speculate about the reasons. Perhaps a more complex social environment, urbanization, and adaptation to more rules and expectations resulted in a noticeable change that affected all modern races,” says Dr. Kubinyi.
The results are consistent with previous research showing that ancient breeds known for their independence are less susceptible to human cues and bark less, indicating differences in visual and acoustic communication compared to modern breeds. (PAP)
Marek Matacz
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