No matter what they do – all is forgiven when they show the puppy dog eyes…how did they learn the trick?

They are known as man’s best friend and have been around 30-40,000 years. Dogs became domesticated to help humans during the hunter/gatherer phase of development. And the bond has stuck ever since.  Europe, Canada and the US are the most bonded to their dogs. “Puppy dog eyes” started around 1910 in popular journalism and has stuck. It is a reference to the sweet, adoring way dog can look at you…especially if they have done something wrong or in need. And it seems, the reason dogs have puppy dog eyes is do to man. This seemingly simple movement of eyebrows is proof of canine evolution and is due to their constant companionship with their pet parents.

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A study published in the Journal of the National Academy of Sciences explains dogs’ faces are capable of complex expressions thanks to a pair of muscles located near their eyes. By pulling their inner eyebrows dogs are able to give us the famous and adorable stare, facilitating human care and improving their communication skills.

The study, conducted by the University of Portsmouth, was interested in how dogs controlled their brows and how this movement was used as a tool for communication. Researchers gathered some dogs and studied these two muscles, finding that they work in tandem to widen and open dog’s eyes. Results showed dogs move their eyebrows more often when humans paid attention to them and less often when they were ignored or given food. These findings suggest that the eyebrow movement is voluntary, and that dogs use it to express their needs.

Other results show that humans tend to respond positively to these arching eyebrows and that people and dogs receive a dose of oxytocin when engaging in eye-to-eye contact.

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In order to learn if this trait was due to human influence, researchers gathered some data on wolves. These animals were unable to replicate eyebrow movements, proving that our decades of adopting dogs as pets have changed some of their behavior.

Dogs may not be able to hunt as ably as they used to, but they can try their hardest to mirror our facial expressions. When it comes to living with humans, cuteness is what matters most.