Four-legged friends are an integral part of our life. It is difficult to imagine how humanity would live without such faithful helpers. The origin of dogs is a question to which there is still no definite answer. There are a huge number of versions, more than a thousand genetic experiments and examinations have been carried out, but the question remains open. Let's try to understand the existing hypotheses and find out why there are so many secrets around the domestication of our four-legged friends.
Evolutionary theory
A dog is a predatory mammal of the canine family. According to evolutionary theory, in the first epoch of the Paleogene period - the Paleocene (about 50 million years ago), a predatory detachment already existed , which, in turn, was divided into two suborders: cat-like and pseudo-like. One of the first representatives of the second suborder is considered such an animal as progesperion. Having carefully studied his fossil remains, we can conclude that he looked like a dog: wide mouth, sharp fangs, high paws, long body. Over time, this suborder was divided into three more groups.
The first group included representatives of the descendants of progesperion, the second - a family of borophages, and the third - wolfs. It is the last family and the origin of dogs that are closely related, because, according to evolutionary theory, our four-legged friends came from wolves.
Assumptions of C. Darwin
The expeditions of C. Darwin on the Beagle ship allowed him to travel to different countries. He, like no other, studied the origin of dogs and tried to find out the truth. C. Darwin established an interesting regularity, which consisted in the fact that dog breeds in certain territories are very similar in their external characteristics to the representatives of the genus Wolves living there. So, for example, in one region the domestic dog was very similar to the foxes living there, and in the other - to the jackals. In different territories, dog breeds resembling local predators really lived.
So, some scientists believe that the origin of dogs is due to the fact that, in the framework of uncontrolled breeding, various animals were crossed: foxes, wolves, jackals, coyotes (since each representative has 39 pairs of chromosomes, they can indeed have a hybrid generation). As a result, each breed had common features similar to one or another species, but at the same time significantly differed from it. Indeed, some breeds are very similar to foxes, and some to jackals. And if we add to this selection and artificial selection, then perhaps the origin of the dog breeds is associated precisely with the crossing of animals of the same family.
Alternative point of view
Despite the fact that the dog still belongs to the type of Wolves, some scientists believe that it came from the "prasobaki". Perhaps 30-40 million years ago there was another squad of predators, which is the progenitor of a domestic dog. There is evidence that in the excavations were found the remains of ancient animals similar to dogs. However, there is no scientific basis or evidence for this point of view.
Dog phenotype and dog breeding
As we have already found out, the history of the origin of dogs is not fully understood. It is difficult to say with absolute accuracy from whom they came. But even greater interest lies in artificial selection and selection. There are about four hundred different breeds of dogs. They differ in height, weight, color, shape of the ears and tail, and many other markers of domestication.
The type of activity whose main goal is the breeding and improvement of dog breeds is called dog breeding. Selective selection is primarily based on the goal of breeding a particular breed of dog. There are three areas: decorative, hunting and service. For each, there are certain requirements: weight, height, head, face, nose, etc.
Interesting information
The smallest breed of dog is, of course, a chihuahua. One of her representatives, Bu-Bu, weighs 600 grams and has a height of 10 centimeters. Chuhuahua is a cute companion animal. They are very shy, curious and observant. But the largest dog (the breed of the Great Dane) - Zeus, has a height of 110 cm and a weight of about 70 kg. This gigantic breed of dogs is very kind and playful, but only in relation to the owners. Representatives of this species are often trained as bodyguards.
The origin of the word “dog” is also covered in many secrets and mysteries. In Russian, it appeared in the 12th century. There are a huge number of versions about the origin of this word. Someone believes that it came from the Turkic “kobyak”, which translates as “domesticated predatory animal”. Over time, the Slavs turned it into a more easily pronounced "dog." A more scientific version, which scholars like Miller and Fasmer are inclined to, is that the word “dog” comes from the Iranian sabāka, which translates as “fast”. Until the 12th century, the animal was called "dog" or "hort." Moreover, it is interesting that the “dog” was used for dogs with thick hair, but the “hort”, on the contrary, for smooth-haired breeds.