How did the domestication of the dog take place during prehistory?

The dog is man's best friend, but he has not always been. At some point in prehistory, humans and wild wolves formed a bond that would grow stronger for thousands of years.

This phenomenon is the domestication of the dog, which has implied its progressive evolution from the wild primordial ferocious wolves to all the breeds of canines that we know today.

The scientific community has tried to find out how, when and where this process first occurred. time, raising several theories based on the genetic findings of different fossils and races modern. Let's see it below.

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When did the domestication of the dog begin?

The domestication of the dog was a gradual process, of which the scientific community has not yet clarified where, when and how it occurred. What is known is that the modern Canis lupus familiaris is a species descended from an early wolf, as is the case with gray wolves. At some point in evolutionary history, those wolves and humanity's best friends parted ways, establishing themselves as two different species. This event had to occur between 15,000 and 40,000 years ago.

Scientists have tried to find out how an animal as dangerous and ferocious as the wolf could, at some point in its existence, end up being such a friendly species that can be found in many homes. Many genetic studies have been done around the globe, analyzing modern breeds and bone remains that have been have been found in Asia and Europe to establish what was the moment in which the domestication of the dog.

The problem is that the matter has not been clarified. The dates proposed by the scientific community vary a lot, and the fact that it is not clear whether it was in Asia, Europe or somewhere in between does not help. It has been agreed to accept that the first domesticated wolves must have lived between 15,000 and 40,000 years ago.

Has it happened several times over the years?

One of the most shocking recent discoveries has been that attempts were made to tame the dog on more than one occasion. Several scientists have analyzed the mitochondrial DNA of 59 different dog remains that lived in Europe, of varying antiquity, between 3,000 years (times close to Ancient Rome) up to 14,000 years. In addition, it was possible to analyze the entire genome of a dog that lived 4,800 years ago and was buried near a prehistoric monument in Ireland.

The genome obtained from these dogs has been compared with that of modern breeds of their congeners and with wolves., suggesting that dogs were domesticated in Asia around 14,000 years ago. Their lineages were divided in two, in the period that would go from 14,000 years to 6,400 years ago, forming the great populations: one in the Far East and another Eurasian.

But, despite this, other fossils older than those have been found in Europe. This finding had given rise to positions, such as that of Thalmann's group, that dogs emerged in Europe and spread from there. However, others have found that this branch, which is supposed to have been the first dogs of history, ended up becoming extinct at some point, being replaced by the races Eurasian.

From these findings it can be concluded that, in fact, the investigations that had ensured that dogs had emerged in Europe or Asia were certainly right. In other words, it is not that today's dogs descend from all those primitive populations, but that It is true that the domestication of the dog took place in various places at different times in history. history.

In addition, this allows for a more open mind, since it allows us to accept the idea that there were more than two domestications, fighting against somewhat recalcitrant positions that had been established in the scientific community regarding this matter, especially among experts Europeans.

How did they become our best friends?

The questions of when and where dogs were domesticated have yet to be fully answered, but, even so, a third question remains: how did prehistoric man manage to tame the big bad wolf?

One of the theories considered is that of defenselessness. A badly wounded wolf was found by some prehistoric human who, instead of killing it, took care of it. The wolf, grateful for the treatment, began to be more meek, accepting the food of his new friend and, soon, he began to have a more protective and friendly attitude towards human beings, a behavior that should have been transferred to others like-minded people. But this explanation is too simplistic and does not have much scientific support.

Another theory holds that prehistoric humans managed to capture wolf pups, keep them as pets, and gradually domesticate them.. This event could have occurred more or less during the agricultural boom, about 10,000 years ago. The oldest fossils of what appear to be dogs date back 14,000 years, but have also been found fossils nearly twice as old of apparently something like a dog or something that should no longer be a wolf primal.

Thanks to the most recent genetic research, it has been suggested that the date of domestication of the dog must have occurred earlier, giving support to a new theory. It shouldn't have happened because an injured wolf became tame, or because pups were kidnapped.

The most plausible explanation is that the original wolves, as with any other species, showed differences in personality, with some being more friendly and others more aggressive. The friendliest ones got closer to humans, without harming them, which must have awakened a less defensive attitude on the part of the prehistoric.

Seeing that the beasts were beneficial for their protection, especially for predators of fields and crops, the humans, little by little, were accepting the company of the wolves and, eventually, taming them.

This domestication involved changes in appearance, making them more "adorable", in the opinion of Brian Hare, one of the expert scientists on the subject. Wolves began to develop more human-friendly traits, traits that must have been long past. few generations, such as floppy ears, longer chest fur, curly tails, and the feeling that they smile when they are breathing through the mouth. mouth.

But it is not only the physical that has changed over the generations. The wolves' own behavior became increasingly geared towards pleasing humans.. They became even friendlier, turning their attention to their new owners and becoming very protective of humans.

Genetic evidence for the theory

A study conducted by evolutionist Bridgett M. vonHoldt of Princeton University offered genetic evidence to support this theory. Dogs, compared to wolves, show higher levels of motivation when seeking interactions with humans. This would show that there is indeed a genetic tendency, shaped by the passage of thousands of years, to promote beneficial behavior towards the human species.

Von Holdt saw that there are regions in the genome of dogs and wolves that are shared, only that there are modifications in dogs. These modifications in the worst regions of the human genome cause Williams-Beuren syndrome, a condition in which the person is extremely trusting and very friendly.

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How much have these animals changed?

Although the exact origins of how the long-standing relationship between humans and dogs was formed, I do it has been discovered how each species has been changing. The differences between dogs such as pugs, dachshunds or poodles are very obvious compared to wolves. But, in addition to this, and as we were already commenting, there are personality differences and, what is most striking, their bond with human beings and their hormonal response.

Research has found that the bond that has been fostered between dogs and humans, learning to work with humans, has impaired teamwork between dogs. Their lifestyle and pack mentality has been reduced compared to wolves, even taking down wild dogs. However, they seem to have developed the ability to solve problems by asking their human owners for help.

An example of this is the experimentation on problem solving between dogs and wolves. For example, if a problem is set to be solved, such as opening a box using a puzzle, dogs and wolves respond differently. Wolves will, as a rule, try to find the solution through trial and error. Instead, dogs first stare at what they have to fix and then turn around looking into their owner's eyes, as if asking for help. This is a very interesting interspecific social behavior that can hardly be observed in other species.

And speaking of looking into the eyes. It has been seen that the brains of dogs and humans are in sync. If a dog and its human owner look into each other's eyes, the brains of both begin to secrete oxytocin, a hormone linked to maternal love and trust. Oxytocin is not unique to dogs and humans, since it is found in other species and has a very important function establishing links between the mother and their offspring or with their peers, but the case of dogs with humans is something that has not been found in other species.

Of course, the way, the moment and the place in which the first human and dog bond was established has been of great importance in the history of the evolution of mankind. A life without dogs is unthinkable, something that could well have happened if their great-great-grandparents (for save us millions of "greats") would not have had the brilliant idea of ​​approaching a group of Hunter-gatherers. What would life be like without dogs? Of course, let's thank the capriciousness of evolution that they made them that way.

Bibliographic references:

• Thalmann, O., Wahlberg, N. (2013) Complete Mitochondrial Genomes of Ancient Canids Suggest a European Origin of Domestic Dogs. Science. DOI: 10.1126/science.1243650.
• B von Holdt, J Pollinger, D Earl, et al. (2012) Identification of recent hybridization between gray wolves and domesticated dogs by SNP genotyping. Mammalian Genome 12 (1-2), 80-88
• M Thompson, B vonHoldt, S Horvath, M Pellegrini (2017) An epigenetic aging clock for dogs and wolves. Age 9(3), 1055-1068.
• MacLean, E. L., et al. (2017) “Individual differences in cooperative communicative skills are more similar between dogs and humans than chimpanzees.” Animal Behaviour, vol. 126, p. 41–51. Scopus, doi: 10.1016/j.anbehav.2017.01.005.