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Puppy dog eyes are no accident

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Even the most cynical human can be softened by puppy dog eyes. You know the look. Those gorgeous wide eyes which shout innocence and all-round cuteness. Dogs often raise their inner eyebrow muscle when greeting people and this makes their eyes look larger. A new study suggests that this wide-eyed expression is no accident but rather the result of evolution.

The study appears to demonstrate that centuries of domestication have resulted in changes to canine anatomy which help humans to better understand their dogs’ emotions.

Canine research reveals changes to eye muscles

The research was led by Juliane Kaminiski from the . She doesn’t believe that dogs move their eyebrow muscles intentionally. Dogs have become tuned to human emotion and their eye muscles have evolved as a result.

Kaminiski has studied dogs extensively and has found that man’s best friend can interpret human gestures better than primates. She was keen to explore the other side of the coin. Can people understand dog behaviour and have the animals adapted to our reactions following their domestication?

The eyes have with canine adoptions

In one experiment, published in 2013, Kaminiski filmed dogs in shelters to discover if any of their behaviours were linked to how quickly they were adopted. She found that the movements of the dogs’ eyebrows upwards and inward was the most significant factor. This was a great surprise and prompted further investigation. She moved on to research whether the eyebrow gestures were unique to dogs or if they could also be found in their ancestors, wolves.

Facial muscle is absent in wolves

The new study, published in , involved analysing the facial muscles of six different dogs and four wild grey wolves. The animal’s bodies had been donated to scientific research following natural deaths.

Interestingly, the levator anguli oculi medialis, a large and prominent muscle was present in all six dogs but it was almost completely absent in the wolves. The retractor anguli oculi lateralis muscle was smaller and more variable in size and presence in the wolves than it was in the dogs. The only exception was the Siberian husky. This breed is closely related to the wolf. The retractor anguli oculi lateralis muscle enables the exposure of the white of the eyes. In other words, it creates a look more like that of humans.

Facial muscles are tiny but can have a huge impact on how we perceive and interpret expressions.

Dogs have the advantage over other pets

The study has demonstrated that over the course of 20,000 years, dog’s faces have evolved to give dogs a significant advantage in their interactions with humans. Their bodies have evolved to be more expressive and of greater appeal. More than that, they have acquired some of the attributes of humans.

Kaminiski intends to conduct further research encompassing ancient breeds to better understand the evolutionary process which has resulted in the muscular changes. She also wishes to look more closely at human reactions to canine eyes and hopes to discover why we find it so hard to resist them.


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