Ultimately, breeding and agriculture have enabled for an increase in life expectancy of the human species. But, at its beginning, that is to say the first hundreds of years of experimentations, these practises could have seemed rather negative: agriculture and sedentary breeding induced a rhythm of life more tiring than the one of hunter-gatherer, and proximity to crops and livestock favoured the emergence and spreading of diseases. A question then arises: how is it that our ancestors persisted in this direction?
In issue 498 (April 2015) of the French science magazine La Recherche, Pierre Jouventin, former research director in ethology at the cnrs, proposes an interesting hypothesis which, in some indirect way, may give an explanation to this enigma1P. Jouventin, 2015. L’Évolution de l’homme sur la piste du loup, La Recherche, 498, pp. 60–65..
It was about − 11,000 when first cultivations started – in the beginnings, mostly cereals. Towards − 9000 started the domestication of animals such as goats, sheep, pigs, beef or cats.
Initially, it was thought that the wolf was domesticated at about the same period.
Oh, yes! A clarification is needed: current state of researches shows that all dog descend from the same line, which separated from wolf under the influence of the Man. Selective breeding made by humans has transformed dogs according its need, leading to the diversity that we know. Not only the rise of dogs is due to human action (that is the domestication of wolves), but it is also human action that caused a strong diversity starting from a single species of wolf.
Not so long ago, it was thought that the wolf was domesticated to become the dog at about the same time as the species mentioned above, to meet the need for herding. Then, it was considered that dog appeared after − 10,000. However, according recent progress in palaeontology, dog appearance is now considered to date to − 36,000. More than 25,000 years earlier than any other domestic species.
Pierre Jouventin’s hypothesis, supported by current research elements, is that Homo sapiens, that is to say our species, could have worked with the wolf while hunting, and then domesticated it. This would have led to a competitive advantage with the Neanderthals, then present in Europe. Neanderthals was stronger and more adapted to that particular environment, while Homo sapiens is an exogenous species capable of living in different environments, but is specialized for none of them. Thanks to the wolf, then the dog, Homo sapiens has become a particularly effective competitor in hunting activities. This may be one of the causes of the disappearance of the Neanderthals from Europe at about − 30,000.
Do not get me wrong: this does not mean that Homo sapiens rejected Neanderthals outside Europe, nor massacred them. This means that the arrival of Homo sapiens and the domestication of the wolf, to make the dog, changed the ecosystem. By this change, Homo sapiens then obtained an evolutionary advantage, that is to say, Homo sapiens’ descendent were more prosperous than Neanderthals’. It could be one of the causes of the disappearance of the Neanderthals.
However, this cooperation between men and wolves, somehow, seems to have been too successful. So successful that it may have caused some imbalances, such that longer travelling were needed to hunt preys that became less common. This put in difficulty the mode of existence of hunter-gatherer. The reaction occurred at about − 11,000, first around Mesopotamia, when man started on agriculture and animal husbandry. Meanwhile, the dog, from hunter became sheepdog, helping to keep the herds.
Thus, the Man has been responsible for the evolution of the wolf to the dog, which dog would in turn had an impact on the evolution of the Man. Each part of an ecosystem affects other parties. In return, these parties have an influence on this first part. The ecosystem is the result of the balance established between each of the parts – the Man is no exception.
That said, we must not forget that other elements were behind the extraordinary triumph of agriculture and herding. Among these, the amazing climate stability we have known for about 10,000 years, which stability is now being compromised.
But trust me: climate will soon be discussed in this blog. View from here, there is much to say …
|P. Jouventin, 2015. L’Évolution de l’homme sur la piste du loup, La Recherche, 498, pp. 60–65.