Study: Evolution To Thank For Cute 'Puppy Dog Eyes'

LOS ANGELES (CBSLA) — Most of us are suckers for "puppy dog eyes." Now, researchers say there's something actually to them!

Experts say your dog's "sad eyes" are more than just an attempt to get a treat. They say it is part of evolution.

Researchers compared a dog's anatomy and behavior to wolves, and found that dogs have learned to move their eyebrows in a way to manipulate. It makes their eyes appear larger and creates that "cute factor."

"That eyebrow movement hijacks our emotions," said one expert. "It triggers some kind of nurturing or care-giving response, not unlike what you see in human parents paying attention to their own infants."

Researchers say a dog's face helps it bond with owners, even more than tail wags.

A prior study found that puppy dog eyes are so effective that dogs with more expressive faces are adopted faster from shelters.