Washington Post – “The mournful, pleading, eyebrows-up expression dogs make is so familiar that we have made it into an idiom: puppy-dog eyes. A study suggests it’s yet another example of dogs’ remarkable ability to communicate with people, one that evolved as the animals were domesticated from ancient wolves at least 15,000 years ago. A specific muscle causes the inner-eyebrow raise that makes dogs’ eyes appear bigger and more infant-like and produces a look similar to one humans make when sad. The researchers found that while six deceased dogs they dissected uniformly possessed this muscle, four dissected wolves either did not have it or barely did. They also found that 27 shelter dogs in the United Kingdom did the eyebrow-raise far more often and intensely when interacting with strangers than did nine wolves at two U.K. wildlife parks.
This suggests ancient canines with expressive eyebrows might have elicited nurturing from humans, the authors write, and that care would have given the animals a selection advantage that allowed them to pass on puppy-dog eyes to their descendants. The study was published in the journal Proceedings of the National Academies of Sciences…” [Note – please consider adoption and rescue.]