Even if you have never had a dog you’ve probably seen one make an expression like the one in the photo above. Dogs can raise their inner eyebrows, making so-called “puppy eyes”. It seems that the dog wants to say “I messed up, but you won’t be angry, right?” Or “You really want to leave me home alone?”
However, wolves – dogs’ closest relatives – cannot make puppy eyes. The muscles of dog and wolf faces are practically identical, except for the single muscle that lets dogs raise their eyebrows. Instead, wolves only have a small tendon, which means they cannot be nearly as expressive with their eyebrows. Additionally, dogs raise their inner eyebrow more often than wolves.
But why do dogs differ from wolves in this respect? It seems that humans, consciously or not, selected for “puppy eyes muscles” and behaviour in dogs.
When dogs pull up their inner brow, they eyes look bigger, more similar to big infant eyes. This facial expression is also similar to the one made by us when we are sad. Dogs with more pronounced puppy eyes may have triggered the human nurturing response. They could have gotten more food, more care and have a higher chance of survival. Even nowadays dogs in shelters that make puppy eyes more often find a new home faster.
Pronounced facial expressions, especially around the eyes, are important in human communication. And it seems important for dog – human communication as well. Even if the dog doesn’t always understand us, its expression may at least give an impression of understanding. Also, dogs more often than other domesticated animals seek eye contact with humans and can follow the human gaze, which helps dog-human communication.
Although I’ve spoken generally here, the facial musculature of just a handful of breeds has been tested so far, but all of them had the extra muscle above the eyes. Except for the husky – the breed most closely (among the studied breeds) related to wolves.
Maybe it’s time to start our own observations? Do you know breeds (or individual dogs) that can’t make puppy eyes?
Photo: Dominika Roseclay, Pexels.com
Polską wersję tego wpisu możesz znaleźć tutaj.