Does your dog have a sad eye? Evolution might be the cause. A team of scientists believe they have found the cause behind the sad eye look that your dog seem to have when he or she is sad. They claim to understand how dogs do to soften people and thus win their affection: two muscles around their eyes help them to have a sad look, a technique found in human babies.
The researchers explain to have dissected corpses of domestic dogs and wild wolves, in an article published this Monday in the magazine of the American Academy of sciences (PNAS), in which they specified that no animal was killed for the study.
The authors found that dogs have two muscles well formed around the eyes, unlike wolves. The two went on their own evolutionary paths some some 33,000 years ago.
In another part of the study, the scientists filmed two-minute interactions between dogs and a human they did not know, and then between wolves and a person. Only the dogs managed to move the eye contour with great intensity when looking at the human.
“These muscular differences are usually not observed in species that are so related,” said Anne Burrows of Duquesne University in Pittsburgh, author of the study published in the journal Proceedings of the National Academy of Sciences.
“This helped them to enlarge their eyes, as babies do,” Anne Burrows, a professor at Duquesne University in Pittsburgh and co-author of the study, told journalists. “That provokes a reaction of protection in the people”.
The work is added to similar ones, among them one carried out in 2015 by scientists in Japan. The result of that study showed that the exchange of glances between dogs and their masters caused a mutual peak of oxytocin, the so-called “love hormone”. It’s the same thing that happens when a mother and her baby look at each other.
This recent research published on Monday only studied the case of four wolves and six domestic dogs. It would be necessary to dissect more animals to confirm the results, the authors of the work acknowledged.
They also want to study old dog breeds and compare them with their current descendants like the Chihuahuas, and study other man-friendly species such as horses and cats.