László Garamszegi et al. (2023) conducted a large-scale analysis of brain size across 159 dog breeds using high-resolution CT scans. The study aimed to determine whether breed function, skull morphology, life history traits, or selective breeding influenced relative brain size evolution in dogs.
The results confirmed that dogs consistently have smaller brains relative to body size than wolves, a hallmark of the domestication effect. Interestingly, breeds more distantly related to wolves exhibited relatively larger brains than those closely related to their wild ancestors, suggesting some evolutionary divergence since domestication.
However, the analyses showed no significant associations between functional breed categories, longevity, litter size, or skull shape and relative brain size. This suggests that despite extensive selective breeding for tasks such as hunting, guarding, or companionship, these factors did not drive further brain size evolution.
The findings highlight that while domestication reduced canine brain size, subsequent breed diversification focused on morphology and behavior did not alter this evolutionary trend. The study underscores the enduring impact of domestication on canine neuroanatomy.
Source: Garamszegi, L., Kubinyi, E., Czeibert, K., Nagy, G., Csörgő, T., & Kolm, N. (2023). Evolution of relative brain size in dogs – no effects of selection for breed function, litter size or longevity. Evolution; International Journal of Organic Evolution, published April 18, 2023.
