According to the findings of a new study, the brains of domesticated dogs have shrunk over the course of evolution. This reduction is primarily due to the fact that the conditions in which these animals live require less brain activity than what their wild ancestors needed. In any case, humans are to blame for these peculiar changes. This was reported by a team of scientists from the Institute of Ecology and Botany at the Center for Ecological Research in Hungary, led by László Zsolt Garamszegi.
The researchers reminded us that dogs are a species of canids that were domesticated at least 15,000 years ago. They also noted that there are currently over 400 dog breeds on the planet. The general trend is that the relative brain size of these breeds has significantly decreased compared to their ancestral species, the gray wolf. Veterinarians and researchers agree that the brains of dogs have been shrinking over centuries of domestication. Whether it involved finding food, escaping predators, or seeking mates, domesticated dogs faced fewer challenges compared to their wild counterparts. As a result of reduced cognitive demands, the brains of domesticated dogs have gradually decreased in size, as reported by the Daily Mail. The scientists explained, “This phenomenon is a result of the decreased need for metabolically costly brain tissue in a domesticated environment.”
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How the Research Was Conducted
The team aimed to determine whether the brain of a domestic dog is indeed smaller (relative to its body size) compared to the brains of its wild relatives. The researchers analyzed the brain and body sizes of 25 canid species, including the domestic dog (Canis familiaris), the gray wolf (Canis lupus), and the raccoon dog (Nyctereutes procyonoides). They found that the brain size of domesticated dogs has significantly decreased compared to their wild ancestor, the gray wolf. However, overall, the domestic dog still has a relatively large brain compared to some other species. Interestingly, the raccoon dog is a “notable exception” regarding brain size reduction. In other words, the brain of the raccoon dog is remarkably small for its body size. The scientists suggested that this is because it is the only canid that hibernates.
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According to the scientists, hibernation is associated with prolonged periods of low metabolic activity and food scarcity. Therefore, it likely contributes to the reduction in brain size. “Extended periods of food scarcity, such as during hibernation, hinder brain development due to permanently high energy demands,” the researchers explained. They concluded that while the domestication of dogs is indeed linked to a decrease in brain size, another reason for this metamorphosis is hibernation, at least among wild canids. The results of the study were published in the journal Biology Letters.