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Scientists discover the truth behind ‘puppy dog eyes'

Nothing can make a dog owner feel quite as soppy as when their beloved pup gives them the old ‘puppy dog eyes’. But it turns out we’re not just being overly sentimental. Scientists have discovered that dogs have actually evolved a special eye muscle that allows them to communicate better with humans.

The muscle in question is called the levator anguli oculi medialis (or LAOM) and enables dogs to ‘raise’ their eyebrows and make their eyes appear bigger, which is what gives them that adorable ‘pleading’ look that we all go soft for. The new study compared the facial muscles of grey wolves and six different breeds of dog and found that the wolves did not have the LAOM muscle required to give them ‘puppy dog eyes’.

This suggests that over the thousands of years that dogs have become domesticated, humans may have subconsciously selected dogs with expressive eyebrows. The researchers studied the behaviour of dogs and wolves and found that when approached by a human, dogs raised their eyebrows more often and in a much more exaggerated way than wolves.

Lead author of the study and professor at the University of Portsmouth, Juliane Kaminski, told Journal Sentinel:

“When dogs make the movement, it seems to elicit a strong desire in humans to look after them. This would give dogs that move their eyebrows more of a selection advantage over others and reinforce the ‘puppy dog eyes’ trait for future generations.”

This suggests that thousands of years ago, a dog that was able to make their eyes appear bigger and more like those of a human child would perhaps have been given shelter and protection and received a caring response from a human.

The effect of this muscle is so great that Kaminski and her colleagues even found that it could have an impact on how quickly dogs were adopted from shelters.

As the study continues, Kaminski and her team will investigate the prevalence of the LAOM in other breeds of dog and species such as coyotes and foxes.