We modern humans feel pretty smug about Neanderthals. It's the story winners often tell themselves about losers: They couldn't cut the mustard, they weren't smart or tough or adaptable enough. To us survivors, there is a moral to the Neanderthals' story: We're still here because we played the game better, worked harder, made fewer mistakes. The Neanderthals were obviously not very smart since they went extinct.
But why do we think that? In science, there's this concept called parsimony — the idea that the simplest explanation that fits the evidence is the one that's probably correct. And evidence that Neanderthals were anything but intelligent, resilient and innovative is thin on the ground. We know they nursed their sick and elderly, buried their dead, made tools and ornaments, ate their vegetables, and the species made it work for hundreds of thousands of years in the inhospitable Eurasian wilderness. Heck, our ancestors even mated with them in the 5,000 years our species overlapped — most modern Europeans and Asians have roughly 2 percent Neanderthal DNA.
An October 2017 study published in the journal Nature Communications applies a little parsimony to the extinction of everybody's favorite hominin heel. In the process of trying to find out just what our ancestors' advantage over Neanderthals might have been, the Stanford-based research team created and tested (and tested, and retested) a model that assumes there was no advantage at all. The surprising finding was, no matter what variables they plugged into the model, the result always eventually spelled D-O-O-M for Neanderthals, the differences being in exactly how long it took them to die. This led the researchers to conclude that the Neanderthal extinction might very well have been a function of population dynamics, and not one species' superiority over another.
The research team found that while it's possible Neanderthals met their demise at the hands of disease, climate change, or just getting thoroughly owned by our ancestors (these are just a few of the theories knocking around out there), it's just as possible that their populations simply fizzled out under the pressure of increasingly more hominins cruising in from Africa.
One of the fundamental truths of community ecology is that it is difficult for two similar species to occupy the same ecological niche at the same time. At the time modern humans were moving into Eurasia, the possible territories that could have sustained groups of hominins in the area were limited. And while all the Neanderthals that existed on Earth already lived between Europe and central Asia, troops of modern humans kept wandering north out of Africa, wedging themselves into the already cramped northern habitats. Over time, the Neanderthals became outnumbered and were eventually replaced completely.
Point being, if their positions were reversed — if the Neanderthals had been the ones constantly sending in reinforcements, and our ancestors had continually been swamped by newcomers — it's very likely our fates would have been reversed as well.
So, there's really nothing to feel smug about after all.