The extinction of the Neanderthals about 40,000 years ago may have been caused by the slow and steady migration of humans from Africa into Europe, according to a new study. Neanderthals and humans co-existed in Europe around 50,000 years ago, and while humans continued to flourish thereafter, Neanderthals went extinct.
Neanderthal Extinction Caused By Random Species Drift
To understand why humans survived and Neanderthals did not, scientists Marcus Feldman and Oren Kolodny created a computer model of interaction between populations of both the species.
The model showed that Neanderthals became extinct in 12,000 years of having existed with humans, even without added factors of climate change or selective evolutionary advantage where one species outperforms another because of specific characteristics or traits.
The scientists found that irrespective of whether modern humans had evolutionary advantages over Neanderthals, they were always going to replace the latter as a result of the evolutionary phenomenon of random species drift.
Moreover, even in a selectively neutral setting, the replacement was certain to take place due to the estimated migration pattern near the beginning of the interaction between Neanderthals and humans.
“We have also demonstrated that even if bidirectional migration between Europe and Africa had occurred, [modern humans] would have been extremely likely to eventually replace Neanderthals, given the estimated differences in population size between the species, in favor of [modern humans],” the researchers wrote.
The origin of the Neanderthals can be traced back to 400,000 years ago in Europe. Neanderthals and humans began to cross paths around 100,000 with the latter’s migration to Europe.
Gradually, the two species started to have more close encounters as they co-existed and interbred for between 10,000 and 15,000 years. In fact, 2 percent of human DNA comes from Neanderthals.
Around 40,000 years ago Neanderthals went extinct and scientists have suggested two main theories in the past few years. One explanation was attributed to climate change because the extinction of Neanderthals coincided with a period of extreme cold in Western Europe, which would have put immense stress on the Neanderthals.
The other suggestion put forth by researchers is Neanderthal and human competition, where humans with their bigger brains and better environment adaptability had a better chance of survival and Neanderthals did not.
Researchers, in fact, do not hold these two factors as mutually exclusive and suggest a combination of the two causing the extinction of Neanderthals. Now, the new model by Feldman and Kolodny says that Neanderthals were doomed irrespective of climate and the evolutionary advantage of humans.