Many people have pets, with almost two times more cats than dogs — 33.7 million versus 18.9 million. A similar picture in other countries of the world. Why are cats and dogs the closest of domesticated animals to man?
The love of dogs sits deep in our genes. According to estimates by Swedish scientists who have studied these 35 thousand pairs of twins, the desire to have a four-legged friend by more than 50 percent is determined by genetic factors.
What genes form the desire to become the owner of the dog is not yet clear. But it is quite possible that they are somehow connected with our perception of dog mimicry. Indeed, in the process of domestication in these animals the anatomy of mimic muscles has changed. In dogs, the two key muscles LAOM (levator anguli oculi medialis) and RAOL (etractor anguli oculi lateralis) are arranged slightly differently than their wild ancestors wolves. The first raises the inside of the eyebrow, the second pulls the outer corner of the eye to the ear. Because of this, the dog’s eyes seem larger, and their expression of the muzzle seems to be a little offended.
According to American and British biologists, people like it, because it resembles the expression of an offended or distressed person. And it is likely that this particular feature of dogs is associated with the desire to take care of them. The authors of the paper note that animals, which more often and more intensely move their eyebrows, as a rule, are picked up faster from shelters than their less emotional relatives.
This assumption is also supported by the fact that during visual contact between a dog and a man, oxytocin is released in both organisms. This hormone stimulates confidence and creates a sense of affection. So, it is he who is involved in creating an emotional connection between mother and child. Obviously, a similar reaction can develop only in response to some external features of dogs, Japanese researchers note.
For dogs themselves, the release of oxytocin makes it possible to better read human emotions and build social relations within the host family. In this sense, they are even greater masters than our closest relatives of chimpanzees.
The same developed mimic muscles, like a dog, has another great friend of a man – a horse. As American and British specialists have found out, the expressions of the faces of these animals are much more diverse than those of some primates, and in some parameters their mimics even coincide with human ones. The muscles around the mouth, ears and nose are especially well developed.
The researchers watched 15 hours of video recordings of the expressions of the faces of 86 horses. They identified the basic units of facial expression – stretching the lips, blinking, etc. – and compared them with human ones. It turned out that the artiodactyls of such elementary movements are 17 (for chimpanzees and dogs – 13 and 16, respectively) and most of them coincide with the movements of human faces. For example, even despite the lack of eyebrows, horses manage to raise the skin above the inner corner of the eye, as we do when we move our eyebrows.
In addition, as it turned out, horses not only masterfully read a person’s emotions, but also know how to relate them to his voice and memorize. When scientists specially presented animals with photographs of angry and unsmiling people, the horses subsequently tried their best to avoid those who were depicted in these photographs.
But if the animal has something to its liking, then it will definitely bring it to the owner. Most often, snorting is a sign of approval, but some horses have been trained to use symbols to communicate with a person. And they coped with this no worse than chimpanzees and gorillas.
The only mystery is the cat. Her mimicry is less rich than that of dogs or horses. Thus, American and British scientists counted only 15 motor units that express the animal’s emotions, and this number, in addition to facial expressions, also included the position of the ears and tail. In addition, the behavior of modern domestic cats are not too far from their ancestor – the steppe cat (Felis silvestris lybica), who led a single nocturnal lifestyle.
But, as it turned out, mimicry the cat to anything, she takes caress. Observing for several months at the animals from six months to 14 years old, living in three British shelters, experts found that people more often chose those cats that rubbed more intensively about various objects in the cage. Such behavior increased the chances of finding a master by almost 30 percent. At the same time, friction functions are still not clear, but researchers assume that they can mean friendliness and submission.
In addition, cats are almost the best in the animal world are able to read human emotions. In an experiment by scientists from the University of Auckland (USA), 12 cats began to behave differently depending on whether their owners smiled or frowned. In the first case, the animals rumbled, climbed on their knees to the people and tried to be close all the time. In the second they ran away from the owners.
According to the authors of the work, the ability to correctly interpret human facial expressions is a skill acquired in the process of domestication. However, this does not mean that cats are capable of empathy, as their owners think. They are simply interested in the neighborhood with a person, because it simplifies survival, the researchers emphasize.
However, some experts suggest that humans are attracted to cats not by their affection, but by ordinary intracellular parasites.
Toxoplasma (Toxoplasma gondii) considers a person as an intermediate host, that is, inside our body it can only be in the form of larvae. But the cat – already the main owner of Toxoplasma gondii – it needs for sexual reproduction. That is why fluffy pets can seem so attractive to people. There is a hypothesis that parasites are able to influence the work of the host brain and force, for example, infected mice not to be afraid of cats. It is likely that something similar happens with the brain of a person who has had toxoplasmosis. True, there are no scientific papers confirming or refuting these assumptions.