The dog is a very unusual creature. She never bothers with questions about your mood, she is not interested in whether you are rich or poor, stupid or smart, a sinner or a saint. You are her friend. That's enough for her.
These words belong to the writer Jerome K. Jerome, whom many of us know from the work "Three in a boat, not counting the dog" and the film adaptation of the same name with Mironov, Shirvindt and Derzhavin.
Dogs have been constant companions of man for many thousands of years. They are our friends, helpers and sometimes a support, without which it is difficult to live (what are guide dogs, rescue dogs, etc.). Such a long coexistence has affected not only us and our attitude towards dogs, but also dogs, not only in a behavioral, but also in an anatomical sense. Today we will get acquainted with the study of the physiognomy of dogs, in which scientists have found evidence that our smaller brothers have evolved, adapting to us. What kind of anatomical changes were found, why are they needed and how do the emotions of a dog differ from those of a wolf from the point of view of physiognomy? The answers await us in the scientists' report. Go.
Research basis
Many thousands of years ago, not particularly intellectually gifted, wild and not domesticated predators walked the earth - people. In the neighborhood with people lived a great variety of animals and plants. Some representatives of the flora and fauna were later domesticated by man for their own purposes, as a result of which we now have pets and fields of wheat. However, the origin of the domestication process is still uncertain, especially in terms of the connection between man and the wolf (later the dog). Some believe that people began to tame wolves, others that wolves themselves began to approach people, due to their close proximity.
Rock image of a joint hunting of a man and a dog (Tassilin-Adjer Plateau, Algeria)
We cannot say exactly how the relationship between man and dog began, but we know for sure what benefits both parties had from this symbiosis. Although people of those times could not write a dissertation on quantum physics, they perfectly understood from their own observations that wolves / dogs have a number of outstanding characteristics: good hearing, a keen sense of smell, the ability to run fast and bite painfully. Consequently, first of all, man used domesticated dogs for hunting, guarding his home and pastures of domesticated cattle. You can also highlight a few other useful "skills" of dogs - they eat and they are warm. It sounds strange, I know, but dogs in human settlements acted as orderlies (like ants in forests), finishing off the remains of human food. And on cold nights, dogs served people like living radiators.
Boar Hunt (1640, painted by Frans Snyders)
In addition to the practical benefits of dogs, there was also a socio-cultural one. Scientists believe that it was thanks to dogs that some aspects of the behavior of ancient people changed: marking the territory and group hunting.
It is possible to consider our ancestors not the smartest, and therefore not the most cultured creatures, but this will be an erroneous statement, which is also refuted in relation to a person to a dog, among other things. Archaeologists around the world find burials of a man and his dog. Pets were not killed after the death of their owners, do not worry. The dog died a natural death and was buried in the owner's grave.
Excavations of the burial place of a man and his dog (age from 5000 to 8000 years).
This is only a brief description of the relationship between our ancestors and dogs, but it is already becoming clear that a dog for a person has always been something more than just an animal with fangs, paws and a tail. The dog has become the same social element of human society, like any individual person.
And what is one of the most important elements of socialization? Of course, the ability and ability to communicate, that is, to communicate with each other. It's easier for us, people - we know how to speak. Dogs, on the other hand, do not have such an opportunity, because they use everything that they have in their arsenal so that we can understand them: tail wagging, growling or barking and facial expressions, or rather muzzles. And here the most interesting begins. There are 43 facial muscles in a human (correct me if this number is wrong). Thanks to this amount, we can express a very wide range of emotions, comparable to a color gradient, in which there are both basic tones and shades. We can say nothing, not move, look at one point, and only a slightly raised eyebrow will already be a sign of a certain emotion. What about emotions in dogs? They have them, let's note for a start. How do they express them? They jump, wag their tails, bark, growl, whine and raise their eyebrows. The last point is the merit of a person, to some extent. Prehistoric dogs, like modern wolves, lack certain muscles that allow domestic dogs to make a facial expression called "puppy eyes."
This is precisely the essence of our study today. Now let's take a closer look at its details.
Results of the study
First of all, scientists note that people have certain subconscious preferences when it comes to faces (the word βmuzzleβ somehow does not want to be used) of domestic animals, namely paedomorphism - the presence of childish facial features in an adult person or animal. In our case, pets also have such features - a high forehead, large eyes, etc. This is due, according to some researchers, to the fact that a child seems to be a harmless creature, but a pet (although it is domestic) still remains an animal whose behavior cannot always be predicted.
This theory is very peculiar, but it finds its confirmation even in cinema, especially in animation.
As you can see, Toothless has very big eyes, and for a reason. Due to this, we subconsciously perceive it with a positive emotional color, despite the fact that we have a dragon in front of us. And the dragon is not a ram sneezing for you (ask the inhabitants of King's Landing).
In any case, when the subjects were asked to choose from a series of images of animals that they liked best, the majority chose those pets that had paedomorphic features.
Scientists also believe that such features can be enhanced by the work of certain muscles, that is, they were "artificially" enhanced. Accordingly, there is already a certain logic in raised eyebrows in dogs, explaining why a normal person cannot resist such a facial expression.
There are muscles due to which the inner part of the eyebrow rises, which makes the dog's eyes look so big and sad. But do wolves have such muscles? Maybe they just do not use them, because their communication with a person is very limited. No, wolves do not have such muscles, because they evolved in a different way.
In order to prove this, scientists conducted a study of the structure of the facial muscles of gray wolves (Canis lupus, 4 samples) and domestic dogs (canis famisis, 6 samples). It is worth noting that all specimens for dissection were provided by the Museum of Medicine, i.e. the animals died of natural causes and were not euthanized for research. Also, observations were made of the behavior of wolves (9 individuals) and dogs (27 individuals) during communication with a person, which made it possible to observe first-hand muscle activity on the face, so to speak.
Image #1
As can be seen from the schematic comparative image of the facial muscles of a dog (left) and a wolf (right), in both versions the muscles have the same features, except for one detail - the muscles around the eyes.
Dogs have a muscle called Levator anguli oculi medialis (LAOM) was fully present and developed, while the wolves had only minor and undeveloped muscle fibers, heavily covered with connective tissue. Quite often, the presence of a tendon was observed in wolves, which grew together with the medial sections of the fibers of the orbicularis oculi muscle in the place where LAOM was present in dogs.
Image #2 (not for the faint of heart): head dissection of a dog (left) and a wolf (right) showing the difference (green outline).
This apparent difference in muscle structure suggests that it is more difficult for wolves to raise the inner part of their eyebrows.
In addition, there were also differences in muscle retractor anguli oculi lateralis muscle (RAOL). This muscle was present in both dogs and wolves. But in the latter, it was mild and was only an accumulation of muscle fibers.
Table comparing the structure of the facial muscles of wolves (C. lupus) and dogs (C. familiaris). Designations: P β the muscle is present in all samples; V β the muscle is present, but not in all samples; A β the muscle is present in most specimens; * - the muscle was missing in one of the wolf samples; β - the muscle in wolves was not presented as a complete one, but as an accumulation of fibers; β‘ The muscle was found in all canine specimens except for the Siberian Husky (could not be detected during dissection).
The RAOL muscle pulls the lateral angle of the eyelids towards the ears. Most domestic dogs have this muscle, except for the Siberian Husky, as this breed is older, more closely related to wolves than other breeds.
These findings of the study of the anatomy of wolves and dogs were confirmed during behavioral tests. 27 dogs were brought from different kennels, to which a stranger approached them in turn and filmed their response to him for 2 minutes. The wolves were brought in from two different establishments where they lived with their packs. An unfamiliar person also approached each of the wolves (9 individuals) and filmed their response for 2 minutes.
"Puppy eyes," which the scientists gave the more severe code name AU101, were analyzed and classified according to intensity, ranging from low (A) to high (E).
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 = β3.13, P = 0.001).
Comparison of AU101 intensity between species showed that low intensity (A) occurs with equal frequency in dogs and wolves. Increased intensity (C) occurs more frequently in dogs, while maximum intensity (D and E) occurs exclusively in dogs.
The reaction of wolves during observations indicating the intensity of expression of AU101:
Intensity A
Intensity B
Intensity C
The reaction of dogs during observations indicating the intensity of expression of AU101:
Intensity A
Intensity B
Intensity C
Intensity D
E intensity
Researchers' findings
The results of the study of the muscular structure of dogs and wolves, together with the behavioral observations made, provided irrefutable evidence that mimic muscles were formed in dogs during domestication. Scientists find this surprising, since this process began as recently as 33 years ago. The difficulty of conducting such studies lies in the fact that soft tissues (in this case, muscles) can not always be found in the form of fossils. Therefore, it is necessary to use other research methods. In this work, modern wolves were used, which did not depart anatomically very far from their ancestors, unlike domestic dogs.
The next conclusion is that the appearance of facial muscles is directly related to the close communication between dogs and humans. Raising the inner part of the eyebrows, the dog makes his eyes bigger, thereby causing a subconscious association in a person with something safe, good and requiring a positive emotional response. This is not so strange, given the importance of eyebrows in human-to-human communication. The movement and position of the eyebrows plays an important role in the placement of accents during a conversation, as certain emotional markers. People subconsciously follow the eyebrows of the interlocutor with special attention.
So far, one thing is not clear - thousands of years ago, during selection, people knew about the mimic muscles of dogs and deliberately tried to breed new breeds that would have them, or this anatomical feature was not studied by people and was passed down from generation to generation without the participation of selection in any of its form? The answer to this question has not yet been found, but scientists do not stop searching.
For a more detailed acquaintance with the nuances of the study, I recommend looking at .
Finale
The dog is man's best friend. Many thousands of years ago, people and dogs began to live together, caring for the good of each other. And even now, in the era of technological progress, when some super fancy robot can do any dog ββjob, we still prefer our four-legged friends.
Dogs perform many important and complex tasks, ranging from searching for missing people after accidents to helping blind owners. But even if your dog is not a rescuer or a guide, you still love her and sometimes trust her more than people.
Dogs, like any other pets, are not just living toys in the house, they become family members and deserve appropriate respect, care and love. After all, as Jerome K. Jerome said: β...she is not interested in whether you are rich or poor, stupid or smart, sinner or saint. You are her friend. That's enough for her."
Friday off-top:
How to behave so that you are not punished for some dirty trick? It's simple, you have to be as sweet as those repentant dogs. π
Friday off-top 2.0 (cat edition):
There is no greater weakness for cats than boxes. And it does not matter that not everything can fit. π
Thanks for watching, stay curious, love the animals and have a great weekend everyone!
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