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Neanderthals--those brawny, heavy-browed but big-brained cousins of ours--thrived across Europe and Asia for some 300,000 years. Then, in the course of just a few thousand years, they vanished, leaving only some bones, beads, stone tools, an enigmatic burial or two, and a scattering of their genes in our species, Homo sapiens.
Since the discovery of the first H. neanderthalesis skeleton in 1856, scientists have speculated and argued about what caused their extinction. There have been lots of ideas, including climate change, disease, lack of genetic variability, interbreeding with, competition with, or outright extermination by H. sapiens.
New research using a dynamic supercomputer model incorporating climate shifts, geography, food resources, utilization of resources and interbreeding solves they mystery. It was us, modern humans at first filtering in from Africa and then expanding our range across Asia and Europe, who did them in.
According to the study, the extinction of the Neanderthals didn't require warfare and slaughter at our ancestor's hands; all that was needed was a competitive edge. Models in which those early modern humans could exploit local resources more efficiently and so support a larger population inevitably showed the Neanderthal range and population shrinking and, within a few thousand years, vanishing. The researchers call this "competitive exclusion."
"It is not a coincidence that Neanderthals vanished just at the time when Homo sapiens started to spread into Europe," says Axel Timmerman, a climate physicist at Pusan National University, in South Korea. "The new computer model simulations show clearly that this event was the first major extinction caused by our own species."
The model that Timmerman developed folded together a huge amount of information. It modeled the climate across northern Africa, Asia and Europe over the 100,000 years that preceded the Neanderthal extinction around 38,000 years ago, regional productivity of potential food sources, population densities of Neanderthals and modern humans across time and space, and interbreeding between the two species.
Running the model on the ALEPH supercomputer at Pusan National University, Timmerman was able to see the shifting populations of Neanderthals and H. sapiens across Asia and Europe over the millenia under different conditions of climate, interbreeding and competition.
One factor that emerged clearly was that climate change alone was not the cause of the Neanderthal's extinction. This bears out the observation that they had survived hundreds of thousands of years of climate change, including periods of severe glaciation. "Neanderthals lived in Eurasia for the last 300,000 years and adapted to abrupt climate shifts that were even more dramatic than those than occurred during the time of Neanderthal disappearance," says Timmerman. It was only after the arrival of modern humans that Neanderthal populations began an irreversible decline.
Timmerman concludes that the anatomically modern humans who found their way into Eurasia around 50,000 years ago simply out-competed the Neanderthals. His model doesn't specify exactly what differences drove that competitive edge. Even if the modern humans simply were able to harvest more food from the environment, or were more resistant to diseases, or managed to raise more children to adulthood, that could have been enough to allow them to displace and eventually replace the Neanderthals.
In other words, one way or another, the culprit was us.
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You can find the full, open-source research paper at this URL. It's worth scrolling down to the appendix, where you can watch movies depicting the influx and growth of the H. sapiens population and the decline and disappearance of the Neanderthals over time and space. Fascinating.
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REA
Since the discovery of the first H. neanderthalesis skeleton in 1856, scientists have speculated and argued about what caused their extinction. There have been lots of ideas, including climate change, disease, lack of genetic variability, interbreeding with, competition with, or outright extermination by H. sapiens.
Reconstruction of a Neanderthal woman
Credit: Bacon Cph
New research using a dynamic supercomputer model incorporating climate shifts, geography, food resources, utilization of resources and interbreeding solves they mystery. It was us, modern humans at first filtering in from Africa and then expanding our range across Asia and Europe, who did them in.
According to the study, the extinction of the Neanderthals didn't require warfare and slaughter at our ancestor's hands; all that was needed was a competitive edge. Models in which those early modern humans could exploit local resources more efficiently and so support a larger population inevitably showed the Neanderthal range and population shrinking and, within a few thousand years, vanishing. The researchers call this "competitive exclusion."
"It is not a coincidence that Neanderthals vanished just at the time when Homo sapiens started to spread into Europe," says Axel Timmerman, a climate physicist at Pusan National University, in South Korea. "The new computer model simulations show clearly that this event was the first major extinction caused by our own species."
The model that Timmerman developed folded together a huge amount of information. It modeled the climate across northern Africa, Asia and Europe over the 100,000 years that preceded the Neanderthal extinction around 38,000 years ago, regional productivity of potential food sources, population densities of Neanderthals and modern humans across time and space, and interbreeding between the two species.
Running the model on the ALEPH supercomputer at Pusan National University, Timmerman was able to see the shifting populations of Neanderthals and H. sapiens across Asia and Europe over the millenia under different conditions of climate, interbreeding and competition.
One factor that emerged clearly was that climate change alone was not the cause of the Neanderthal's extinction. This bears out the observation that they had survived hundreds of thousands of years of climate change, including periods of severe glaciation. "Neanderthals lived in Eurasia for the last 300,000 years and adapted to abrupt climate shifts that were even more dramatic than those than occurred during the time of Neanderthal disappearance," says Timmerman. It was only after the arrival of modern humans that Neanderthal populations began an irreversible decline.
Timmerman concludes that the anatomically modern humans who found their way into Eurasia around 50,000 years ago simply out-competed the Neanderthals. His model doesn't specify exactly what differences drove that competitive edge. Even if the modern humans simply were able to harvest more food from the environment, or were more resistant to diseases, or managed to raise more children to adulthood, that could have been enough to allow them to displace and eventually replace the Neanderthals.
In other words, one way or another, the culprit was us.
-----
You can find the full, open-source research paper at this URL. It's worth scrolling down to the appendix, where you can watch movies depicting the influx and growth of the H. sapiens population and the decline and disappearance of the Neanderthals over time and space. Fascinating.
-----
REA
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