According to researchers, the facial features of dogs have evolved over time. This evolutionary change has allowed dogs to display a variety of facial expressions, particularly the “sad eyes” look. Research suggests this evolution helps to improve and facilitate human-dog relationships.
Findings reported by the University of Portsmouth imply that the facial structure of dogs has changed over the centuries to enable them to specifically communicate with humans. Dogs have an inner eyebrow-raising muscle which triggers and creates the “sad eyes” expression. In comparison, other animals, like wolves, do not.
The authors suggest that the inner eyebrow-raising signifies a nurturing response in humans because it makes their eyes appear bigger and more infant-like. The results also imply that expressive eyebrows may be the result of humans unconscious preferences that “influenced the selection of domestication”. Thus, this gives dogs an evolutionary advantage over other animals and reinforces the desired “puppy eyes” for future generations. The findings also imply that the behaviour is intended for human consumption.
Previous research by Dr Kaminski also showed that dogs moved their eyebrows significantly more when humans looked at them compared to when humans were not looking at them. It could be evolution’s way of manipulating your feelings for your dogs!