If the dog has accompanied man for more than 300 centuries, the process of its domestication is still far from having delivered all its mysteries. Does the wolf, his ancestor, still slumber in him? Every month, new discoveries force scientists to rewrite our common history.
WHEN DID THE DOG BECOME DOMESTICATED?
The dog is man’s oldest friend. While most animal domestication (mainly breeding) goes back 10 or 12,000 years, the oldest traces found concerning the dog are more than 30,000 years old! And this in several European countries such as the Czech Republic, Belgium or Russia. In France, in the Chauvet cave, the prints of a canidae found next to those of a child suggest a companionship of more than 300 centuries! In these remote times, the dog is physically very close, even similar, to the wolf, and it is not easy to distinguish between the two. Scientists believe that these first contacts are isolated cases and have not been followed up. In fact, the ancestors of our current companions would have been tamed much later. Evidence was first discovered in Asia and dates from 10,000 to 12,000 years ago. Since then, a study conducted in 2016 in part by the CNRS suggests that the dog comes from not one, but two independent domestications: one in East Asia, about 12,500 years ago, and another in Europe 15,000 years ago. Then, between the 5th and 4th millennia B.C., dogs from Asia would have migrated to Europe, probably at the same time as human populations. There, they would have reproduced with native Europeans. It is their descendants who would have taken over.
WHO IS THE ANCESTOR OF THE DOG?
The majority of researchers currently agree that the grey wolf (Canis lupus) is the ancestor of all dogs. However, this has not always been the case. The idea that the dog was descended from the jackal or was a hybrid between the jackal and the wolf was once widespread. Today it has been completely abandoned, as genetics has indeed made the difference. According to the results obtained, the dog and the wolf share more than 99.5% of their genetic heritage, a much higher percentage than with any other species of the genus Canis (wolf, coyote, jackal and dog). Some scientists, however, put forward another hypothesis, according to which the dog is not descended from the grey wolf, but from a closely related species that is now extinct. This would explain why contemporary wild dog breeds do not resemble the grey wolf.
DO WILD DOGS EXIST?
It is not easy to give a definition of the wild dog. Indeed, we must not confuse the hare dogs or pariah dogs on the one hand and the wild dogs on the other. The first, which could also be called stray, are in fact domestic dogs which, if they have no owners, live thanks to man, feeding most of the time on his food waste. Wild dogs, on the other hand, do not need humans to exist. This is the case of the Australian dingo and its close relative the New Guinea singing dog. They have the peculiarity of having been domesticated before returning to the wild. A pack of singing dogs, a species thought to have disappeared from the wild since the 1970s, was observed in 2017. In contrast, other wild dogs, such as the African wild dog in Africa or the Asian dhole in Asia, have never been domesticated. Neither of them are classified in the genus Canis.
WHY DID MAN TAME THE WOLF?
Our direct ancestors, the homos sapiens, lived in Europe 30,000 years ago. On their hunting grounds, they often encountered packs of wolves. Humans and canids stalked the same prey and, certainly, quite similarly; small game when they went alone or large herbivores when they hunted in groups. They often had to watch each other, compete for prey when it became scarce, and after the hunt, one might be the scavenger of the other. The prevailing hypothesis is that one day a hunter probably brought back a cub that had not yet been weaned. Perhaps to eat it or to please his children. As the cub grew up, the children made him a companion and the women enjoyed his company. Such a meeting took place in several places on the European continent. While the vast majority of these contacts were not followed up, perhaps one day a wolf raised among the men gave birth in the clan… And that’s how it all began. It was only later that the humans discovered that their companions could sound the alarm, unearth game, protect their children and, why not, amuse them…
CAN THE DOG BECOME A WOLF AGAIN?
The only dogs that have been returned to the wild are the Australian dingo and its cousin, the New Guinea song dog. Their ancestors were probably domesticated in Asia between 18,000 and 6,000 years before our era. From there, they accompanied their masters in their long migrations to Australia and New Guinea. About 5,000 years ago, the dingo and the song dog became wild again. Are they, however, wolves again? If, like the wolf, the dingo lives in a pack composed of a couple and litters of different ages, physically, it still resembles the first dogs domesticated by man. Unlike dogs and wolves, the dingo is not able to bark, but sneezes loudly when it feels threatened. As for the singing dog, if it howls like the wolf, it is with a long modulated complaint that belongs only to him. In fact, history teaches us that evolution never goes backwards: the dog that becomes wild again does not become a wolf, but another animal, the fruit of its history, its environment and its evolution.
WHY IS IT SAID THAT THE DOG IS AN INFANTILISED WOLF?
The adult dog retains certain characteristics that the wolf cub loses as it ages. This biological particularity is called neotenia. Thus morphologically, the adult dog has a short muzzle, drooping ears and shorter limbs. In its behaviour, it barks and barks like a cub. He also spends a lot of time playing. According to some researchers, this “eternal youth” is linked to domestication. Man would have preferred (voluntarily or not) individuals with childlike traits, more reassuring. Others believe that it is the fact of being housed, fed and protected that has made the dog an adolescent for life. In both cases, since domestic animals reproduce earlier than their wild counterparts, they pass on traits that are characteristic of their young age to their offspring. Finally, the craze for certain breeds (such as the fashion for small, round-headed dogs with big, innocent eyes) also influences the species. Other breeds, on the other hand, have few juvenile traits, such as the Asian breeds, which are considered to be close to the primitive breeds.
WHAT DO THEY UNDERSTAND ABOUT US?
All dogs identify a few words learned by training or in a more empirical way by associating a word or an object with an activity (“walk”, “babble” …). But, much more than words themselves, our companions are sensitive to prosody, i.e. the tonality or modulation of the sentence with which it is pronounced. Thus, they react positively to a playful voice or more negatively to a sad, harsh or even neutral tone. Scientific research has also shown that dogs can tell the difference between a friendly face and an angry face and adapt their behaviour accordingly. They are one of the few species that understand pointing and look at the object they are pointing at rather than the finger pointing at it. The sense of smell also allows him to perceive many things about us. This sense being on average one hundred thousand times more developed in him than in humans, each small molecule of smell teaches him more about us, our mood, even our diseases, than any great speech or medical examination. A word, a tone, a smell and an attitude, it is by associating all these elements that the dog manages to “make a sentence” to understand us sometimes much better than ourselves.
WHAT ARE THE OLDEST BREEDS?
Spitz and related breeds such as huskies, samoyeds and Asian dogs (akitas and shibas) form a large family of so-called “primitive” breeds. Today they are considered to be the oldest. These dogs, which hardly ever bark, are reputed to have an independent and rather stubborn character. Molosses and dogs resembling greyhounds appeared later, some 3,000 years ago. Chinese texts describing dogs similar to today’s Pekingese date back 2,500 years, and nude dogs were already living in Mexico 1,000 years BC. During antiquity, dogs had the same functions as they do today. Some are dedicated to work (shepherding, guarding, hunting and war), others to companionship and live in homes. From the Middle Ages onwards, large hunting dogs, dear to the lords, appeared and were selected. But it was in the 19th century that breeds multiplied and were set to meet specific characteristics such as size, coat color, or even physical aptitudes. Currently, there are 340 breeds and most of them are recent creations.
HOW DOES HE KNOW HOW TO MAKE HIMSELF UNDERSTOOD?
The news fell at the beginning of the year: it is thanks to their eyebrows that dogs make us crack! Compared to wolves, they have developed extra muscles around the eyes to better communicate with humans. By frowning, the dog provokes in us the irrepressible desire to take care of him. He also has a very wide range of barks that he addresses to us depending on the situation. The strongest thing is that we understand them since in more than 40% of cases, humans perceive the animal’s emotional state as aggressiveness, despair, fear, joy or the desire to play. And to better attract our attention, to tell us that it’s time for a walk or to point out the box of kibbles or the urgency of a situation, the dog displays attitudes, gestures, looks that we can easily interpret…
SHOULD THE MAN BEHAVE AS A PACK LEADER?
Under the pretext that the wolf is the ancestor of the dog, it has long been explained that the master must behave as the leader of the pack, be the dominant male, in this case the father of the family, the dogs having to be at the very bottom of the ladder. This vision is now outdated. Firstly, because ethologists have discovered that wolf packs were not composed of a dominant couple who would rule the pack, but of a family composed of a couple raising several generations of cubs. We should therefore speak rather of parental authority than of sovereign domination… Secondly, because studies on hounds have shown that the latter never constituted packs, but more or less flexible groups with different interactions between individuals. Conflicts arise over food, access to females, but most often they are settled by postures and rarely by fighting. This lack of hierarchy in dogs naturally calls into question the very idea that it can exist between man and dog.
IS THE DOG STILL A PREDATOR?
Like the cat, the dog still retains an important part of its hunting instincts. In France, as everywhere else in the world, canine attacks on chickens or sheep are legion. On the other hand, there are few studies on the impact of dogs on wildlife. However, cases of predation are reported on local species such as iguanas in the Galapagos Islands or those in the Turks and Caicos Islands. In 2016, a Polish team estimated the number of wildlife killed by dogs on its territory at 33,000. In parts of Africa, feral dogs compete with large predators. For example, dogs harassing wolves in Abyssinia have been observed in Ethiopia. The presence of domestic dogs can also cause a decrease in wildlife reproduction due to the stress it causes. This anxiety leads to a change in the behaviour of other animal species (change in spatial distribution, more frequent search for refuge). Finally, a study showed a 35% decrease in the diversity and 41% decrease in the abundance of birds in an Australian forest where dogs are frequently walked.
HAS THE DOG REPLACED THE WOLF ON EARTH?
Some scientists more or less seriously put forward the hypothesis that it is not man who tamed the wolf, but the opposite. According to them, wolves have come closer to humans so that their species could find an environment favourable to their survival. A strategy that seems to have succeeded since the population of their domesticated offspring – dogs – is estimated at between 500,000 and one billion, while that of wolves has never ceased to decrease to around 200,000 to 400,000 individuals today. Has the dog replaced the wolf on our planet? No, for the simple and good reason that dogs do not occupy the same ecological niche and are therefore not in competition. In the majority of cases, the disappearance of wolves, like that of large carnivores, is attributable to humans either by direct destruction of the species or by devastation of their environment. That said, dogs could pose another, much more insidious threat to wolves: introgression. This scientific term refers to the presence of dog genes in 11% of the wolves studied by a team of researchers. The dingo, the Iranian wolf, the Iberian wolf and the golden jackal would also be concerned by this “genetic invasion”. These hybridizations could have serious consequences for the conservation of these species, which are often threatened.
IS A NEW DOMESTICATION POSSIBLE?
The circumstances that led to the domestication of the wolf into the dog took place over thousands of years and, as we presume today, with many failures. Renewing the experiment is therefore impossible. On the other hand, in order to understand its mechanisms, the Russian scientist, Dmitri Beliaïev, decided in the 1960s to reproduce the process, in an accelerated manner, with Siberian silver foxes bred for fur. He first selected the most docile foxes before breeding them. Then, at each litter, he continued to select the most friendly individuals towards humans. In only about fifteen years, the fox has become a dog both in its behavior (wagging its tail when seeing its master, barking and loving to play) and physically, with a shortening of the jaw and legs, a larger skull and a diversification of the color of its fur. His experience shows that, even taking only one criterion into account, it is the whole genetic makeup of the animal that evolves. This is probably what prehistoric man did with the first wolves, but in a more empirical way!
IS THE DOG MADE TO WORK?
Once the dog was domesticated, man quickly realized that it could be a formidable auxiliary in daily life, as much for guarding, hunting as for war (later). As the ethologist Charlotte Duranton writes: “The selection carried out over the centuries, through different breeds, even within different lineages, has developed particular aptitudes and skills, both physical, intellectual and behavioural. These qualities have allowed the breeds to specialize in this or that action, to accomplish their “duty” with the best possible baggage and the fewest constraints. This is, for example, the case of water working dogs, whose legs are now webbed, making their swimming more efficient and therefore less tiring. It is also the case of search dogs, which combine physical endurance and great olfactory capacities. Hunting or herding dogs, for their part, have been selected on the basis of specific behaviors acquired from a very young age and which they learn to master until adulthood. This work of genetic selection, as we know, influences the behavioural tendencies of individuals. “In our modern societies, full of technicalities, dogs have never helped man so much. In addition to their traditional jobs such as guarding or hunting, they now work in the search for missing persons, detecting explosives or drugs, intercepting individuals, detecting cancers or providing moral support… If they feel like it!