2023-12-24 16:49:48
Updated Sunday, December 24, 2023 – 15:49
A group of researchers has discovered that facial images of dogs with brown eyes are perceived as friendlier and this potentially provokes desires for care on the part of humans.
A dog of the Shiba Inu breed.EMRedes A woman walks a man who pretends to be a dog on a leash through Valencia
Most of the dogs They have brown eyes because humans preferred it that way during domestication when they were friendlier and less threatening than wolves, whose eye color is usually yellow.
That is the conclusion of a study carried out by five researchers from the Teikyo or Showa Universities of Sciences (Japan), and published in the journal ‘Royal Society Open Science’.
Comparative studies have shown that the morphology of the primate eye has been determined by a variety of selection criteria, such as communication or environmental factors.
The authors carried out an analysis of the morphology ocular of the oldest domesticated animal in the world, the dog (‘Canis familiaris’), and its closest relatives, the wolf (‘Canis lupus’). In the case of dogs, they selected facial images of individuals from 33 breeds.
They compared their irises in order to evaluate whether dogs’ eye colors affect in the way human beings perceive them.
Dogs were domesticated from wolves between 15,000 and 50,000 years ago, through both natural and artificial selection.
The eye color of dogs seems to be darker than that of wolves. The color of the eyes in both animals is determined mainly by the color of the iris because most of the sclera is not exposed externally and their pupils are usually dark.
Non-threatening looks
The iris color of wolves is usually classified as yellow, while that of dogs can be described as dark brown or black. A darker iris color is recommended in breeding programs for most purebred dogs.
The irises of dogs They are significantly darker than those of wolves. The researchers discovered that facial images of dogs with brown eyes are perceived as friendlier and this potentially provokes desires for care on the part of humans.
“Our findings are consistent with our expectation that humans prefer dark-eyed dogs over light-eyed dogs and provide an updated hypothesis that dark-eyed dogs may have evolved to acquire a facial feature that sends a non-gaze signal. threatening to humans,” they indicate.
The researchers note that “in general, dogs with dark eyes may have developed this trait largely as a means of sending non-threatening gaze signals to humans.
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