{"id":35569,"date":"2019-10-31T22:05:06","date_gmt":"2019-10-31T19:05:06","guid":{"rendered":"https:\/\/prohoster.info\/blog\/shhenyachi-glazki-30-000-let-koevolyutsii-sobaki-i-cheloveka\/"},"modified":"2019-10-31T22:05:06","modified_gmt":"2019-10-31T19:05:06","slug":"shhenyachi-glazki-30-000-let-koevolyutsii-sobaki-i-cheloveka","status":"publish","type":"post","link":"https:\/\/prohoster.info\/en\/blog\/news\/shhenyachi-glazki-30-000-let-koevolyutsii-sobaki-i-cheloveka","title":{"rendered":"\"Puppy Eyes\": 30,000 Years of Dog-Human Coevolution","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\""Puppy<\/p>\n

Dogs are very unusual beings. They never pester you with questions about your mood; they don't care if you're rich or poor, foolish or wise, a sinner or a saint. You are their friend. That is enough for them.<\/p><\/blockquote>\n

These words belong to the writer Jerome K. Jerome, whom many of us know from the book 'Three Men in a Boat, Not to Mention the Dog' and the film adaptation featuring Mironov, Shirvindt, and Derzhavin. <\/p>\n

Dogs have been constant companions of humans for many thousands of years. They are our friends, helpers, and sometimes support systems, without which life can be difficult (just think of guide dogs, rescue dogs, etc.). Such a long coexistence has influenced not only us and our attitude towards dogs but also the dogs themselves, in both behavioral and anatomical senses. Today, we will explore a study on canine physiognomy, in which scientists found evidence that our smaller brothers have evolved by adapting to us. What specific anatomical changes were discovered, what are their purposes, and how do dogs' emotions differ from wolves' emotions from a physiognomic perspective? The answers await us in the researchers' report. Let's go.<\/a><\/noindex><\/p>\n

The foundation of the research<\/h3>\n

\nThousands of years ago, the Earth was inhabited by not particularly intellectually gifted, wild, and untamed predators\u2014humans. In the vicinity of humans lived a great multitude of animals and plants. Some representatives of the flora and fauna were later domesticated by humans for their purposes, resulting in our current pets and fields of wheat. However, the origins of the domestication process remain uncertain, especially concerning the connection between humans and wolves (which later became dogs). Some believe that humans started to tame wolves, while others think that wolves began to approach humans due to their close proximity. <\/p>\n

\""Puppy
\nCave painting of a joint hunt between humans and dogs (Tassili n'Ajjer plateau, Algeria)<\/i><\/p>\n

We cannot say for certain how the relationship between humans and dogs began, but we definitely know the benefits that both sides have gained from this symbiosis. People of that time, although unable to write a dissertation on quantum physics, understood from their own observations that wolves\/dogs possess a number of outstanding characteristics: good hearing, a keen sense of smell, the ability to run fast, and the capacity to bite hard. Therefore, humans primarily used domesticated dogs for hunting, guarding their homes, and protecting their livestock pastures. There are also several other useful 'skills' of dogs \u2014 they eat and they provide warmth. It may sound strange, I know, but dogs in human settlements served as sanitation workers (like ants in forests), finishing off the remnants of human food. And on cold nights, dogs served as living radiators for people.<\/p>\n

\""Puppy
\n\"Boar Hunt\" (1640, painting by Frans Snyders)<\/i><\/p>\n

In addition to the practical benefits of dogs, there was also a socio-cultural aspect. Scientists believe that it was thanks to dogs that certain aspects of ancient human behavior changed: territorial marking and group hunting. <\/p>\n

One might consider our ancestors not the smartest, and therefore not the most cultured beings, but this would be a mistaken assertion that is refuted in relation to the human-dog bond, among other things. Archaeologists around the world find burials of humans and their dogs. The pets were not killed after their owners died, do not worry. The dog died a natural death and was buried in its owner's grave. <\/p>\n

\""Puppy
\nExcavation of the burial of a human and its dog (age between 5000 to 8000 years).<\/i><\/p>\n

This is just a brief description of the relationship between our ancestors and dogs, but it is already clear that the dog has always meant more to humans than just an animal with teeth, paws, and a tail. The dog has become as much a social element of human society as any single individual.<\/p>\n

What is one of the most important elements of socialization? Of course, it is the ability and skill to communicate with one another. It is easier for us humans \u2014 we can talk. Dogs, however, lack this ability, so they use everything in their arsenal to help us understand them: wagging their tails, growling, barking, and facial expressions, or rather, expressions of their muzzles. This is where things get interesting. Humans have 43 facial muscles (correct me if I'm wrong about this number). With such a number, we can express a wide range of emotions, comparable to a color gradient that includes both primary tones and shades. We can say nothing, remain still, stare into one point, and just a slightly raised eyebrow can indicate a particular emotion. But what about dogs' emotions? They do have them, let's note that first. How do they express them? They jump, wag their tails, bark, growl, whine, and raise their eyebrows. The last point is partly due to humans. Prehistoric dogs, like modern wolves, lack the specific muscles that allow domestic dogs to make the facial expression known as 'puppy eyes.'<\/p>\n

This is precisely the essence of the study we are examining today. Now, let\u2019s take a closer look at its details.<\/p>\n

Research Results<\/h3>\n

\nFirst and foremost, researchers note that humans have certain subconscious preferences when it comes to the faces (the word 'muzzle' feels awkward to use) of domestic animals, specifically neoteny \u2014 the presence of juvenile facial features in adult humans or animals. In our case, such features are present in pets \u2014 high foreheads, large eyes, etc. This is believed by some researchers to be because a child appears to humans as an innocent creature, while a domestic pet (even though it is domestic) remains an animal whose behavior cannot always be predicted. <\/p>\n

This theory is quite unique, yet it is supported even in cinema, particularly in animation.<\/p>\n

\""Puppy
\nAs you can see, Toothless has very large eyes, and it's not without reason. This feature subconsciously evokes a positive emotional response from us, even though he is a dragon. And a dragon is not like a sheep sneezed (just ask the residents of Royal Harbor).<\/i><\/p>\n

In any case, when the subjects were asked to choose from a range of animal images which ones they liked the most, the majority chose pets that exhibited neotenic traits.<\/p>\n

Researchers also believe that such traits can be enhanced by the action of specific muscles, meaning they were 'artificially' amplified. Accordingly, there is a certain logic behind the raised eyebrows in dogs, explaining why an ordinary person cannot resist such a facial expression.<\/p>\n

There are muscles that raise the inner part of the eyebrow, which makes a dog's eyes appear so large and sad. But do wolves have such muscles? Perhaps they simply don\u2019t use them, as their interaction with humans is quite limited. No, wolves do not have these muscles, as they have evolved down a different path.<\/p>\n

To prove this, scientists conducted a study on the facial muscle structure of gray wolves (Canis lupus<\/i>, 4 samples) and domestic dogs (Canis famisis<\/i>, 6 samples). It should be noted that all samples for dissection were provided by a medical museum, meaning the animals died of natural causes and were not killed for research. Observations were also made of the behavior of wolves (9 individuals) and dogs (27 individuals) during interactions with humans, allowing for first-hand observation of facial muscle activity, so to speak.<\/p>\n

\""Puppy
\nImage No. 1<\/i><\/p>\n

As seen in the schematic comparative image of the facial muscles of a dog (on the left) and a wolf (on the right), in both cases the musculature has identical features, with the exception of one detail \u2014 the muscles around the eyes. <\/p>\n

In dogs, the muscle known as levator anguli oculi medialis<\/i> (LAOM) was fully present and well-developed, while in wolves there were only minimal and underdeveloped muscle fibers, heavily covered with connective tissue. Often in wolves, a tendon was observed that fused with the medial parts of the fibers of the circular muscle of the eye at the point where LAOM was present in dogs. <\/p>\n

Image No. 2 (not for the faint-hearted): dissection of a dog's head (left) and a wolf's head (right) highlighting the differences (green outline).<\/b>\""Puppy
\n
\nThis obvious difference in muscle structure indicates that wolves find it more difficult to raise the inner part of their eyebrows.<\/p>\n

In addition, differences in the muscle were also observed. retractor anguli oculi lateralis muscle<\/i> (RAOL). This muscle was present in both dogs and wolves. However, in wolves, it was poorly developed and consisted only of a cluster of muscle fibers.<\/p>\n

\""Puppy
\nComparison table of facial muscle structure in wolves (C. lupus) and dogs (C. familiaris). Designations: P<\/b> \u2014 muscle is present in all samples; V<\/b> \u2014 muscle is present, but not in all samples; A<\/b> \u2014 muscle is present in most samples; *<\/b> \u2014 muscle was absent in one of the wolf samples; \u2020<\/b> \u2014 muscle was not represented in wolves as a full muscle, but as a cluster of fibers; \u2021<\/b> \u2014 muscle was found in all dog samples except for the Siberian Husky (could not be detected during dissection).<\/i><\/p>\n

The RAOL muscle pulls the outer corner of the eyelids towards the ears. Most domestic dogs have this muscle, except for the Siberian Husky, which is a more ancient breed, thus more closely related to wolves than other breeds. <\/p>\n

The findings of the anatomical study of wolves and dogs were confirmed during behavioral tests. 27 dogs were brought from different kennels, to which an unfamiliar person approached one by one, filming their reaction to him for 2 minutes. Wolves were delivered from two different institutions where they lived with their packs. An unfamiliar person also approached each of the wolves (9 individuals) and filmed their reaction for 2 minutes.<\/p>\n

The 'puppy dog eyes,' which researchers gave the harsher code name AU101, were analyzed and classified based on intensity, ranging from low (A) to high (E).<\/p>\n

Comparison of AU101 frequency between species showed that dogs use this facial expression significantly more often than wolves (Mdn = 2, Mann-Whitney: U = 36, z = \u22123.13, P = 0.001).<\/p>\n

Comparison of AU101 intensity between species showed that low intensity (A) occurs with the same frequency in both dogs and wolves. Increased intensity (C) occurs more frequently in dogs, while maximum intensity (D and E) occurs exclusively in dogs.<\/p>\n

Wolf reactions during observations with intensity of expression AU101:<\/b>\""Puppy
\nIntensity A<\/i><\/p>\n

\""Puppy
\nIntensity B<\/i><\/p>\n

\""Puppy
\nIntensity C<\/i><\/p>\n

Dog reactions during observations with intensity of expression AU101:<\/b>\""Puppy
\nIntensity A<\/i><\/p>\n

\""Puppy
\nIntensity B<\/i><\/p>\n

\""Puppy
\nIntensity C<\/i><\/p>\n

\""Puppy
\nIntensity D<\/i><\/p>\n

\""Puppy
\nIntensity E<\/i><\/p>\n

Researchers' conclusions<\/h3>\n

\nThe results of the study of the muscle structure of dogs and wolves, combined with behavioral observations, provided undeniable evidence that domestic dogs developed facial muscles during domestication. Scientists find this remarkable since this process began only about 33,000 years ago. The complexity of conducting such research lies in the fact that soft tissues (in this case, muscles) are not always detectable in the form of fossils. Therefore, alternative research methods must be employed. This study utilized modern wolves, which have not deviated significantly anatomically from their ancestors, unlike domestic dogs.<\/p>\n

The next conclusion is that the emergence of facial muscles is directly related to the close interaction between dogs and humans. By raising the inner part of their eyebrows, dogs make their eyes appear larger, subconsciously triggering an association with safety, goodness, and a positive emotional response in humans. This isn't surprising considering the importance of eyebrows in communication between people. The movement and position of eyebrows play a crucial role in emphasizing points during conversations, serving as certain emotional markers. People subconsciously pay special attention to their interlocutor's eyebrows.<\/p>\n

One thing remains unclear \u2014 whether thousands of years ago during selection people were aware of dogs' facial muscles and intentionally tried to breed new breeds with this trait, or whether this anatomical feature was unknown to humans and passed down through generations without any form of selective breeding. The answer to this question has yet to be found, but scientists continue their search.<\/p>\n

For a more detailed understanding of the nuances of the research, I recommend checking out the the scientists' report<\/a><\/noindex>.<\/p>\n

Epilogue<\/h3>\n

\nA dog is a man's best friend. Thousands of years ago, humans and dogs began living together, caring for each other's well-being. Even now, in the age of technological progress, when any dog task can be performed by some high-tech robot, we still prefer our four-legged friends. <\/p>\n

Dogs perform many important and complex tasks, ranging from searching for missing persons after accidents to assisting blind owners. But even if your dog isn't a rescue dog or a guide, you still love and trust them sometimes more than people. <\/p>\n

Dogs, like any other pets, are not just living toys in the house; they become family members and deserve the respect, care, and love that comes with it. As Jerome K. Jerome said: '...it doesn\u2019t matter if you are rich or poor, foolish or wise, a sinner or a saint. You are her friend. That's enough for her.'<\/p>\n

Friday off-topic:<\/b>

\r\n \"Play\r\n
<\/div>\r\n <\/div><\/center>
\nHow to behave so you won't be punished for some mischief? It's simple; you have to be as cute as these remorseful dogs. \ud83d\ude42<\/i><\/p>\n

Friday Off-Topic 2.0 (cat edition):<\/b>

\r\n \"Play\r\n
<\/div>\r\n <\/div><\/center>
\nThere is no greater weakness in cats than boxes. And it doesn't matter that not all of them fit. \ud83d\ude42<\/i><\/p>\n

Thank you for your attention, stay curious, love animals, and have a great weekend, everyone! <\/p>\n

Thank you for staying with us. Do you enjoy our articles? Would you like to see more interesting materials? Support us by placing an order or recommending us to your friends. 30% discount for Habr users on a unique entry-level server designed by us for you:<\/b> The whole truth about VPS (KVM) E5-2650 v4 (6 Cores) 10GB DDR4 240GB SSD 1Gbps starting at $20, or how to properly divide a server?<\/a><\/noindex> (options available with RAID1 and RAID10, up to 24 cores and up to 40GB DDR4).<\/p>\n

Dell R730xd for half the price?<\/b> Only with us 2 x Intel TetraDeca-Core Xeon 2x E5-2697v3 2.6GHz 14C 64GB DDR4 4x960GB SSD 1Gbps 100TB starting at $199<\/a><\/noindex> in the Netherlands! Dell R420 \u2014 2x E5-2430 2.2GHz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB \u2014 from $99!<\/b><\/b> Read about how To build a corporate-class infrastructure using Dell R730xd E5-2650 v4 servers costing 9000 euros for peanuts?<\/a><\/noindex><\/p>\n

Only registered users can participate in the survey. Please log in<\/a><\/noindex>, please.<\/p>\n

Who is man's best friend?<\/h2>\n