2023-12-22 23:40:34
Dog eye color could be determined by humans. This is what a new study carried out by Japanese scientists and published in the scientific journal Royal Society Open Science suggests, which has discovered that dark eyes are more common in domestic dogs than in their wild relatives, and that humans perceive dark-eyed dogs as friendlier.
According to Molly Selba, an anatomist at the University of Maryland Eastern Shore—who was not involved in the preparation of this work—the results of this study fit with existing research on how humans have changed the appearance of dogs over the course of time. the history.
“It makes sense that eye color is one more place where humans have left their mark,” he says in statements reported by the media Science.
Shape dogs like stuffed animals
As highlighted in Sciencehumans have shaped dogs since they were first domesticated—perhaps 20,000 years ago or more—choosing animals that are friendly, obedient, and good at working with humans.
“We may also have changed their appearance, from their big eyes to their big heads; ‘neotenic’ features that remind us of our own children, transforming dogs not only into companions, but into stuffed babies,” the text states. Science.
For Akitsugu Konno, behavioral scientist at Teikyo University of Science (Japan) and first author of the research, “lighter irises have some evolutionary advantage for wolves, but domestication has lost this selective pressure and eyes have appeared. darker in some primitive dogs,” he says in statements collected by The Guardian.
The team claims that dark eyes may have later been favored by humans, possibly unconsciously, during the domestication of wolves to dogs. However, Konno points out that the later development of certain breeds could also have influenced canine eye color. So, for example, the blue merle coat color seen in breeds such as Shelties and Border Collies is associated with blue eyes.
The importance of color
Konno and his team edited photos of dogs from 33 breeds – from Welsh corgis to Irish wolfhounds – and lightened or darkened their eyes. They showed selections of these images to 142 Japanese volunteers, mostly students, and asked them to rate each dog based on traits such as friendliness, aggressiveness, maturity and intelligence.
The team found that volunteers were much more likely to judge a dog as friendly — rating it higher on traits such as sociability and non-aggressiveness — when the photo showed dark eyes. Participants rated these dogs as less intelligent and less mature, and similar to puppies.
Dark eyes are preferred
The researchers emphasize that the association of dark eyes with immaturity could influence humans to protect and care for these dogs, although the study found that eye color was not directly related to the fact that the participants They would like to interact with the dog or keep it.
“Overall, dark-eyed dogs may have developed this trait largely as a means of sending humans a non-threatening signal with their gaze,” the team writes in statements reported by The Guardian.
Selba, for his part, believes that he would like the team to analyze whether the phenomenon is valid for more than the approximately 350 official dog breeds that exist, and whether color influences the chances of being adopted more quickly or not.
However, there are exceptions, such as Siberian huskies, Konno says. The penetrating blue eyes common in this breed suggest that they could be related to wolves more than to other breeds, especially in terms of their visual anatomy and communication, the researcher highlights in statements collected by Science.
Research is lacking
“We really like telling stories about the domestication of dogs, but it’s been difficult to do solid studies,” says Jessica Hekman, a veterinarian and canine geneticist at the nonprofit Functional Dog Collaborative.
For Hekman, it is possible that dogs acquired dark eyes in recent centuries, but to determine an exact moment, further research would be required.
According to Lisa Gunter, a dog behavior researcher at Virginia Polytechnic Institute and State University, this new study raises interesting questions about canine evolution. However, questions arise about the idea that dark-eyed dogs look younger.
“Because most dogs have brown eyes, people are more familiar with them and may simply prefer what they’re used to,” Gunter says, adding that the fact that dogs’ pupils are dilated usually means that He’s nervous, not that he’s any nicer.
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