"Neanderthals were not inferior to modern humans," said Julien Riel-Salvatore, assistant professor of anthropology at UC Denver and co-author of the study published in Human Ecology.
"They were just as adaptable and in many ways simply victims of their own success," he said. . . .
Riel-Salvatore said the new computer model takes the added step of showing how Neanderthals and homo sapiens roamed farther afield than assumed.
The computer models ran for 1,500 generations, following estimated samples of humans and Neanderthals roving across the two continents.
"You set some baseline parameters and see how these 'agents' interact," said Riel- Salvatore, who co-wrote the study with C. Michael Barton of Arizona State University. One parameter included researchers' knowledge that the last ice age forced Neanderthals and humans to widen their search for food.
They interacted, and because there were far more humans, over time that species diluted Neanderthals until they appear as just a fraction of our DNA.
Evidence of Neanderthal prowess as mates follows a March study co-authored by CU-Boulder, showing Neanderthals were experts at keeping fires burning continually. That skill, key to flourishing, had previously been thought beyond their reach.
"It shows you don't need to depend on the old cliches to explain the disappearance of Neanderthals," Riel-Salvatore said. "You don't need to make assumptions about them being stupid or less flexible."
I have two main criticisms of Riel-Salvatore's take on the matter.
First, the absence of any Neanderthal Y-DNA or mtDNA despite the fact that 1-4% of autosomal DNA in modern non-Africans has a Neanderthal source does not support the kind of admixture dilution model that he is proposing. You need a very specific kind of admixture that takes into account factors like differences between hybrid fertility and intraspecies fertility to get the observed result, and you also need to take into account post-Neanderthal replacements of much of the modern human population of Europe to make the geographic uniformity of the Neanderthal percentages fit what is observed. Also, there is pretty solid evidence to indicate that there were no significantly mixed Neanderthal-modern human communities; tribes from the diifference kinds of hominin mostly kept their distance from each other. There is not a single case of a Neanderthal skeleton and a modern human skeleton buried in the same graveyard in the same culturally continous time frame, although there is evidence of modern humans using caves previously inhabited in prior eras by Neanderthals.
Second, there is a quite strong case to be made that Neanderthals, while more sophisticated than Homo Erectus, for example, were not the intellectual equals of modern humans. Their material culture remained stagnant for 200,000 years, while modern human technologies evolved continuously and at a much higher rate. Some of the technological advances attributed to them during the contact period with modern humans (e.g. the Uluzzian) have been determined to very likely have been modern human tool cultures, and in the cases where there was change in Neanderthal tool culture, the change was probably in lower quality imitation of modern humans and didn't happen until contact took place. Their food sources were much less diverse (they were pretty much exclusively apex predators while modern humans had more fish, although Neanderthals did some non-harpoon fishing, more small game, and more fruit and vegetable gathering). Their geographic range was much narrower (they didn't make into Southeast or East Asia, nor did they make it to Africa, and they had a more limited presence in the far North and Siberia although there are some traces of them in parts of these places). The quantity and quality of Neanderthal artistic expression and symbolic activity was a pale shadow of that of modern humans (they had simple burials but no elaborate paintings or sculptures). The range of materials that Neanderthals used in tools was smaller (e.g. they used far less processed bone and twine). They had less of an ecological impact on megafauna than modern humans, suggesting that they were less successful hunters. Their social groupings were smaller from a quite early point.
You may not have to make assumptions about Neanderthals being stupid or less flexible than modern humans to explain their demise. But, despite having relatively large brains, and genes that would have given them more language abilities than some of their hominin predecessors, there is ample evidence from the material culture that they left behind that they were not as adaptable as modern humans. And, if one can determine that from independent evidence, it isn't unreasonable to include that in models of how Neanderthals went extinct.