It’s hard to say no or stay mad when your pet gives you puppy dog eyes and now science has figured out why. New research suggests that over the thousands of years that dogs have become domesticated, people preferred pooches that could pull off that sad, sweet, appealing expression. And that innocent look has pretty much guaranteed the survival of dogs with humans.
In a new study released by the National Academy of Sciences, researchers find that centuries of living with people encouraged dogs to develop a muscle that lets them raise their eyebrows so they look more baby-like. That muscle is “virtually absent” in wolves, the ancestors of dogs. “You don’t typically see such muscle differences in species that are that closely related,” explains study author Anne Burrows.
Researchers think dogs used this eye muscle to communicate with people and to get them to feed or take care of them. It worked and people obliged and those hard-to-resist puppy dog eyes are here to stay.