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Biologists who compared the facial muscles of dogs and wolves report that dogs have facial muscles that allow them to lift their inner eyebrows, making their eyes appear large or sad. The study suggests that the domestication of dogs by humans has led to this adaptation because humans may view dogs’ eyebrow expressions as an appeal for help, the authors write in PNAS yesterday (June 17).
The muscles were thinner or weren’t present in the four wolf cadavers they dissected (they also examined six dog heads). In behavioral observations, dogs raised their eyebrows more often and more intensely than wolves did.
“You don’t typically see such muscle differences in species that are that closely related,” coauthor Anne Burrows of Duquesne University in Pittsburgh tells the Associated Press. The results points to “how important faces can be in capturing our attention, and how powerful facial expression can be ...
