Why did the Neanderthals die out? Maybe they just melted into Homo sapiens by interspecies crossing? Or did our ancestors exterminate them?
Steve Connor talks about a fossil that could serve as key evidence.
Scientists managed to get one step closer to solving the death of Neanderthals who disappeared from the face of the earth about 30 thousand years ago: a new study concluded that it was a tiny population on the verge of extinction.
Neanderthals first appeared in Europe at least 300 thousand years ago, but after the arrival of people of the Homo sapiens species, anatomically similar to modern humans, came to Europe. The first Homo sapiens came to this part of the world 50 thousand years ago. This circumstance makes one wonder what happened to the Neanderthals: either they, interbreeding with the newcomers, formed a kind of hybrid tribe that dissolved in human genetic diversity, or, conversely, were exterminated by our ancestors as a result of an open struggle or rivalry for livelihood …
The newest physical evidence - DNA analysis from samples taken from a 38,000-year-old fossilized shinbone - indicates that Neanderthals did not interbreed with modern humans, but were exterminated by them.
The DNA of an adult Neanderthal man who lived near caves on the territory of present-day Croatia also indicates that even in the most prosperous times, the number of Neanderthals in Europe probably did not exceed 10 thousand individuals - for the population this is a dangerously small value.
New information about the end of the Neanderthals is extracted from the entire DNA sequence contained in mitochondria - tiny cellular structures. DNA in mitochondria is maternally inherited, and in material taken from old bones it is easier to isolate than what scientists usually work with - the DNA found in the cell nucleus.
Scientists have deciphered 35 times mitochondrial DNA taken from a 38,000-year-old Neanderthal bone to ensure they have found the correct gene sequence suitable for a legitimate comparison with the mitochondrial DNA of modern humans and their closest living relatives, the chimpanzee.
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“This is the first time we have recreated a sequence from ancient DNA that is essentially free of errors,” said Richard Green, who led this research at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
“In the future, it remains to be seen why the population of Neanderthals was so small - was there really always so few of them, or at the end of their existence there was some kind of demographic decline,” said Dr. Green.
Archaeological evidence suggests that Neanderthals and people anatomically similar to modern humans - they are called Cro-Magnons - lived in overlapping periods of time in the same environment and in the same places, but there is no clear evidence of the thesis that direct contact took place between the last two human species and their individuals did live side by side.
“There is no evidence that they saw each other: it is only clear that they lived in the same places at about the same time. I personally believe that they most likely caught sight of each other, - said study participant Adrian Briggs, a researcher at the Max Planck Institute.
“What have we done? We confirmed that the mitochondrial DNA of the Neanderthal was very different from the DNA of modern humans, and this convincingly proves that there was little or no interspecies crossing, Briggs explained.
“In addition, we got an intriguing result that indicates a small population of Neanderthals. What happened to them? Here we can only make assumptions. Small populations are always more susceptible to extinction, because the chances of an unfavorable turn of events increase."
People have been actively speculating about what the Neanderthals were and what their fate was, ever since the first Neanderthal skull was dug up in the Neander Valley near Düsseldorf in 1856.
At the moment, the prevailing opinion is that the Neanderthals were not the direct ancestors of modern man, but only a lateral branch of his branched family tree. However, some anthropologists do not abandon the idea that at one stage or another in their history, Neanderthals interbred with humans, which means that each of us is somewhat Neanderthal.
However, the results of several DNA studies, including the newest one published in the journal Cell, provide little support for this theory. Whenever it was possible to analyze the sequence of severely damaged DNA fragments extracted from the bones of Neanderthals, it turned out that their genetic variations went far beyond the variations observed in modern humans.
For example, the latest research shows that the common ancestor of Neanderthals and modern humans lived about 660 thousand years ago - long before Homo sapiens appeared in Africa as a separate biological species about 100 thousand years ago.
However, the scientists who carried out this study emphasize that their results cannot yet completely rule out the likelihood of a limited, narrow-scale interspecies crossing between Neanderthals and Cro-Magnons somewhere between the Caucasus and Western Europe - in the geographical area of distribution of Neanderthals.
One of the most convincing evidence in favor of this thesis was discovered ten years ago, when scientists found on the territory of modern Spain the skeleton of a boy who died about 25 thousand years ago. His stocky build suggested that we are dealing with a Neanderthal / Cro-Magnon hybrid, but other scientists believe that these are simply innate features.
Undoubtedly, the Neanderthals must have looked very different from those who came to Europe later. The Neanderthal's chest was barrel-shaped, that is, there was practically no waist, which, apparently, seemed even more heavy.
Massive jaws, double brow ridges, due to which the forehead hangs, well-developed muscles - all this gave them the resemblance to blunt bandits. But, although the word "Neanderthal" is associated with idiocy, in reality they were intelligent creatures: they used fire and very intricate stone tools, dressed in animal skins and buried the dead. The presence of the hyoid bone in the apparatus of their larynx suggests that they could speak. However, most experts do not believe that the Neanderthals developed the complex language that was being formed among the Cro-Magnons at that time.
Professor Chris Stringer, head of the Human Origins Department at the Natural History Museum in London, believes that the long period of lack of contact between Neanderthals and Cro-Magnons - and their mutual genetic isolation - means that they have become profoundly different in physical and mental respects.
“Therefore, the question is how these populations perceived each other when they met. As the same people or as enemies, or maybe as completely alien creatures or even as prey? - he explains. - We do not know the answer. Perhaps in different places and different times it was different, especially since people are very changeable in their behavior."
Perhaps we will never know what happened when modern humans came to places inhabited by Neanderthals. Perhaps they simply stayed away from each other, and the Neanderthals retreated to their last stronghold in Europe - the cave system in Gibraltar, where the freshest Neanderthal bones were found.
Or there was a bloody conflict between the species - one of those that at all times are characteristic of the history of mankind.
Genetic differences
Neanderthal
A massive lower jaw and an overhanging forehead - neither give nor take a rugby player on steroids. The rib cage is wheel-shaped - that is, there is no pronounced waist. He used fire and stone tools, buried his dead. There is almost no evidence of behavior behind more abstract thinking. In the apparatus of the larynx there is a hyoid bone, and therefore, he may have mastered speech, but experts doubt the existence of a developed language among Neanderthals. Well adapted for cold climates: the limbs are short, the torso is dense. This probably helped him survive several glaciers that happened in Europe.
Modern type man
The chin and lower jaw are graceful, the double eyebrows are absent, so the face looks more sophisticated. The rib cage tapers downwards, separating the abdominal region from the chest, so that the waist is visible. He used fire and stone tools, buried his dead, performing certain rituals. There is evidence of the development of abstract thinking and the ability to plan for the future. The presence of the hyoid bone indicates that speech was an important element of social organization. The body and limbs are graceful and flexible, which indicates adaptability to warm climates.