Another study uncovered a hormonal mechanism behind the dog’s gaze.

It showed that the same rise in oxytocin levels that promotes bonding and trust between mother and baby is present in dogs and their owners who maintain lots of eye contact.

But this response, and also the eyebrow muscle, is lacking in the grey wolf: the dog’s primary ancestor.

“Over the years, dogs have extended how they talk to us using their gaze with the evolution of the ‘puppy dog eyes’ look, which is designed to pull on our heartstring by mimicking the wide-eyed look of babies,” says K9 Magazine publisher Ryan O’Meara.

“Most dogs are using the power of the gaze as more of a stare to get us to understand what they want from us and owners understand what their dogs are telling them.”

Dogs can “talk” with their owners using their eyes, study finds