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.
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: a wide mouth, sharp fangs, high legs, a 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 the 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 appearance 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 various 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.
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.
About the family - Diodorus
When quarreling with someone, you need to keep in mind that this quarrel is subsequently replaced by friendship. Diodorus
Whatever the ancestors of domestic dogs, we can say with confidence that dogs - these are the first animals tamed and domesticated by humans. The remains of the ancients dogs archaeologists find in various parts of the world. Scientists do not yet know the whole truth about the origin of the domestic dog, some suggest that the ancestors of the present dogs were wolves and jackals, proving this theory by the biological proximity of species, external similarities, similar structural features and behavior. Others believe that domestic dogs descended from several extinct wild species of dogs, and confirm this opinion with a large variety of existing breeds.
Yet most scientists adhere to the first theory, and in the scientific classification, a domestic dog belongs to the family canids, kind - wolves. Most likely, the first domestic dogs took a place next to people as assistants in the hunt, even when the ancient people lived only in hunting and did not engage in cattle breeding and agriculture. Afterwards dogs began to be used for guard service.
On ancient egyptian monuments (3-2 thousand years BC) depicts different breeds of dogs, but most of them resemble modern greyhounds, later images of dogs indicate the distribution of hounds and burrows. There are references to large dogssuch as mastiff. In a word, it is obvious that dogs were widely used in hunting and for guard service already several thousand years ago.
Ancient Greek and Roman sources mention the use of dogs in military affairs. There is evidence of use dogs to protect fortresses, guard duty, and later to attack the enemy specially trained and equipped in protective shells dogs. The past millennia and human efforts to select and form new breeds have greatly changed the appearance of a domestic dog. And, although most modern dog breeds are not at all similar to wolf ancestors, many of the features of the behavior of a wild animal living in a pack are still inherent in them. Today dogs they help people in various fields of activity, are used in the border service, to protect the territory, search for people in disasters, accompany the blind. And representatives of decorative breeds do an excellent job with the role of friend and pet. The question about the origin of domestic dogs is clearly not possible to answer. This process began at the end of the Paleolithic and was practically not documented. The main issues are: from one or more ancestors descended domestic dogs and from whom exactly. The problem has been discussed for a long time, many hypotheses are built.
Proponents of monophilia of the origin of all breeds (i.e. from one ancestor) spoke All buffon breed from shepherd dogs, and explained their diversity by the influence of culture and climate, Guldenstad considered the ancestor of the jackal, Studer suggested that the basis is extinct dog Canis ferus. And today, many zoologists consider the ancestor of a wolf dog.
One of the first to speak about polyphyletic origin French naturalist J. Saint-Hilaire, C. Darwin also adhered to this hypothesis. An interesting scheme of origin dogs, created a century ago by K. Keller, a major pet specialist. He gives the following arguments: first, - domestic dogs, in which the features of the breed are clearly expressed, appear early in areas far apart from each other, and secondly, - dogs resemble those living in the same areas wild caninethirdly, the diversity and heterogeneity of the group pet dogs, which cannot be explained only by artificial selection made with the descendants of one ancestor. Keller identifies the following groups of domestic dogs and their ancestors.
- Spitz-shaped - an ordinary jackal.
- Pariah dogs Asian and African - an ordinary jackal.
- Shepherd dogs - Indian wolf, classified as a subspecies of the gray wolf.
- Greyhounds - Ethiopian jackal. The center of origin is in Ancient Egypt, mentioned back in the days of the Ancient Kingdom.
- Dog-like dogs are a Tibetan wolf, completely extinct, apparently one of the subspecies of an ordinary wolf.
- Dogs of the New World before the appearance of Europeans there.
representatives of wild canine. This approach is not unique to Keller. K. Lorenz divides all dog breeds into “wolf” and “jackal”, depending on which of the ancestors participated more in the formation of the breed, and when determining the type of breed it focuses on the character anddog research.
K.T. Sulimov, Jackal-Dog Hybridization Specialist, notes that the nature of the movements and the general type of behavior of these animal species are very different. This casts doubt on the claim that the jackal may be the dog’s main ancestor. According to Sulimov, they are an extinct species resembling a coyote. A.D. Poyarkov believes that most of the rocks should not be bred from the wolf. The modern fauna is much poorer than the one that existed on Earth when the process of becoming a domestic dog began. Breeding of many breeds from coyote-like ancestors is very likely. The authors of the Catalog of Mammals of the USSR, as well as the famous paleontologist N.K. Vereshchagin as possible dog ancestor They call it not a wolf, but a close, but smaller species, Canis volgensis. Unlike Keller, a number of contemporary authors, such as Ashe Suple, Durel and Deschambres, believe that the group greyhounds comes from a pariah dog and its ancestor is the Indian gray wolf. To summarize, it would be logical to state the main facts and hypotheses.
The domestic dog has the widest range breeds so different from each other in comparison with other domestic animals. The species composition of wild dogs during the domestication of dogs was much wider than now, although among the living members of the family there are species that "claim" the title dog ancestor.
In prehistoric times, many established dog breeds were recorded. In the period of the first civilizations dogs they are already well represented by a wide range of very different groups of rocks, the centers of which are significantly remote from each other.
Many cases of mating dogs with a wolf are known.coyote
red wolf. Mating with an ordinary jackal is possible. Prolific offspring.
Most proponents of monophilia consider the wolf ancestor, and domestication took place in one place, and then the descendants of animals settled on the ground.
All breeds of dogs come from the wolf., but from different subspecies, and domestication took place in different areas independently. Since the participation of the wolf in many breeds is obvious, then if an ancestor is specified a different species, in addition to him, dogs become a polyphyletic group.
The origin of the dogs of the New World, like the dogs of the Southern Hemisphere, it is very poorly studied. There is a hypothesis that the domestication of dogs in the Southern Hemisphere occurred independently of the domestication in the Northern, and Dogs have different ancestors.
The most likely polyphyletic point of viewI. One of the ancestors could be a coyote-like representative of the ancient fauna. Interspecific possible hybridization, which was combined with artificial selection, one of the directions of which was an increase in loyalty to humans.
What happened to the wild ancestors of the dog when domestication began? It is clear that a prerequisite for this process was selection for loyalty and non-aggression towards a person. Many authors, for example, the school of academician Belyaev, call the selection for reduced aggressiveness to humans the most important factor in the domestication process.
How will such selection affect the wild? The following experiment was performed at the experimental center of the Siberian branch under the direction of D.K. Belyaev. Among silver-black foxes for over 20 years, the selection was the least aggressive to humans. As a result, foxes showed signs that did not correspond to the wild form: hanging ears, rounded tails, spotting, increased fertility, and a clear breeding season disappeared. The ratio of experimental foxes to humans has become different. They ceased to be afraid of him, moreover, they appeared to “adore” a person, the need for contact with him. All of these are typical canine symptoms. A similar selection was called destabilizing. It was found that with destabilizing selection, the physiology and biochemistry of animals changes significantly. Thus, we see that the selection for reduced aggressiveness very significantly changes the domesticated look, and the experience with foxes revealed a series of parallels between domesticated foxes and dogs, although foxes
dogs belong to different genders: dogs - to the genus Canis, and foxes - to the genus Vulres. It should not be forgotten that in experiments with the domestication of foxes under the influence of selection, there were a significantly smaller number of generations than in the formation of ancient breeds of dogs. When breeding to reduce aggressiveness, the factor stabilizing the genome is removed, and many previously undeveloped symptoms become apparent. It can be assumed that such a genome becomes more susceptible to foreign influences and the probability of successful interspecific mating increases, the potential base for selection increases. Thus, if we have received a destabilized, “blurred” gene pool either by crossing or preliminary selection to reduce aggressiveness, we have material that is easier to absorb various surges from close relatives. Some confirmation of the above considerations can serve as a long-term work on the hybridization of marteniformes conducted by D. Ternovsky. He managed to get several digibrids (a column of European mink, mink and ferret, etc.) and even a triple hybrid. All hybrids were prolific and breed well in captivity.
Spitz-shaped dogs. One of the oldest groups, which includes many breeds. Divided into subgroups: real Spitz, husky and sled dogs (the breeds closest to the wolf). This also includes Chow Chow. Skeletons of dogs, very similar to Spitz-like, were found in Sumatra and Madagascar. Sled dogs of North America and Greenland are of North Asian origin and belong to the subgroup of huskies and sled dogs.
Many authors, for example, Smychinsky (Poland) classify terriers and pinschers (with schnauzers) as spitz-shaped. Despite the obvious kinship of these groups, it seems to me more appropriate to distinguish terriers and pinschers into independent groups. Terriers began to appear in England in the Middle Ages. Pinschers and schnauzers are breeds of continental Europe, they have been mentioned since the 15th century, so both of these groups are much younger than Spitz-shaped ones and probably come from the latter.
Dog-like dogs - An ancient group of Asian descent. The group is divided into 3 subgroups: large shepherd dogs, real short-haired dogs and long-haired dogs.
The first group includes such breedslike Caucasian, Central Asian, South Russian, Podhalyan Shepherd Dogs, Komondor, Kuvach, Maremma, Pyrenees dog, Anatolian Karabash and Swiss Shepherd Dogs - Mountain Dogs. Probably the ancestor of these dogs was the Tibetan Great Dane.
Group of Pointing Dogs Youngerthan hounds. There are references to small hunting dogs that were used during falconry to scare birds of prey. There are references to similar dogs in Wales in the X century. Real spaniels appear in England in the 14th century. A large group of dogs can be divided into spaniels, retrievers, continental and English cops. Continental gundogs come from hounds and blood hounds. The oldest breeds of this group are various marriages. The small münsterlender also belongs to the subgroup of spaniels and spinon. It is believed that primitive Spitz-shaped dogs participated in its origin. Retriever, English Pointing Dogs, and most of the Continental Pointing Dogs are breeds recently bred from other groups. Thus, Pointing dogs come from hounds and probably spitz-shaped dogs.
Western decorative dogs - lapdogs are quite an ancient group. About dogs, very similar to a lapdog, mention Aristotle and Pliny the Elder. The decorative dogs of China and Japan - Pekingese, pug, hin, representing an independent group, have an even earlier origin. Varieties of Tibetan lapdogs, or, as they are also called, tibetan terriers (having nothing to do with other terriers) can also be considered as a special group. One of the most exotic dogs in the world is shar pei (the breed included in the Guinness Book of Records as the most expensive). She probably stands alone or, perhaps, belongs to the eastern branch of dog dogs.
Allocating New World dogs as an independent groupKeller is certainly right. Perhaps this is not even one group of breeds. About the origin of these dogs very little is known, as is the origin of the dogs of the Southern Hemisphere.
Eaton believes that the domestication of dogs in the southern hemisphere independently, these dogs have their own ancestors. However, studies at the chromosome level by Borgankar, Eliott, and Scott showed that the basenji and teloman (Polynesian hunting dogs) have very similar chromosomes to beagle and sheltie chromosomes. However, these authors themselves come to the conclusion that the pedigree differences (and we will notice that the species differences too) are determined at the gene, and not at the chromosomal level.
Genetics Scott and Fuller hypothesizedaccording to which basenji and dingo arose from a common ancestor who lived in South Asia about 4 thousand years ago.
Although we give here a classification of rock groups, we should not forgetthat these groups with rare exceptions are not isolated from each other. Only the most ancient breeds show a certain purity of origin. Often the variety is presented in the form of a family tree, with each breed derived from one or two. The tree grows from the root, branching more and more. This is how the Mazover classification is built. In our opinion, it does not correctly reflect the process of rock formation. If you trace the origin of any breed, it almost always turns out that it has not one, but two or more immediate ancestors. For example, an airedale comes from crossing an otterhound, a bull terrier and a white terrier (according to one source). According to other sources, possible ancestors are also called collie and setter. In turn, the bull terrier carries the blood of a white English terrier, English bulldog and some other terrier-like dogs. The ancestors of Otterhound are the Welsh Hound, the Water Spaniel, the English Bulldog, the Bloodhound and the French Vendee griffin. Now let the reader remember that in ordinary schemes the airedale is derived from one or two ancestral forms, for example, from a white English terrier or otterhound. It is believed that he is a typical representative of terriers, and nothing more. The Airedale is indeed a representative of a glorious group of terriers, but he carries the blood of the dog dogs that he received from the Bull Terrier and the Otterhound, and blood from the hounds and blood from the cops.
To summarize. We know that when breeding new breeds, as a rule, interbreeding was used, followed by strict selection and closely related breeding of the desired lines. Of course, this is a very general scheme. The question of the origin of dogs is generally much more complicated. However, many facts and experiments that can be used not as evidence, but only as analogies, only as hints, allow you to build a scheme that resonates with that given for one breed. Namely, a scheme in which all the variety of breeds is explained by the polyphyletic origin and powerful destabilizing selection. Hybridization of several species and destabilizing selection for domestication, as it were, mutually reinforce each other and create a huge base for selection in many directions. Probably always the right qualities were fixed by inbreeding. However, I will not undertake to assert that it was so in reality. Other points of view are possible.
Source: "Word about the dog" Korneev
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