Our Neanderthal Cousins May Have Gone Extinct Because of Sex

One of the greatest unanswered questions in human evolution is how the Neanderthals perished. According to a recent study, sex rather than aggression may have caused Homo sapiens to be accountable for the demise of Neanderthals.

Make Love Not War

The Neanderthals may have been driven to extinction by making love, not by fighting. There is little evidence that this process went the other way, although around 2% of the genomes of all living people outside of Africa are descended from Neanderthals.

A recent study suggests that interbreeding with our ancestors may have decreased the number of Neanderthals breeding with one another, ultimately contributing to their extinction. The study was published in the journal PaleoAnthropology.

The authors are hopeful that improvements in DNA sequencing technology will be able to disprove this hypothesis by making more genomes accessible, even though only 32 Neanderthal genomes have been sequenced thus far, leaving it possible that the absence of Homo sapiens DNA in their genome is a quirk of sampling.

The latest study's authors, Professor Chris Stringer and Dr. Lucile Crété, are the Museum's Research Leaders in Human Evolution.

Also Read: Neanderthal's Extinction May Be Caused By an Entirely Different Reason  

Relationship with Homo Sapiens

The relationship between Homo sapiens and Neanderthals has become increasingly sophisticated in recent years. However, Chris notes that "scientific debate of how the interbreeding between the two occurred" is still uncommon.

"We suggest that this behavior if the Neanderthals were routinely reproducing with Homo sapiens, might have contributed to their demise, which could have depleted their population until they vanished."

Around 600,000 years ago, Homo sapiens and Neanderthals split apart and developed in vastly different parts of the globe.

Neanderthal fossils have been discovered in southern Siberia and throughout Asia and Europe. It is estimated that they spent at least 400,000 years adjusting in this setting, where the climate was generally colder than it is now.

The forebears of our species, meantime, developed in Africa. Whether Homo sapiens are the direct offspring of a single group of prehistoric African hominins or the product of genetic admixture between other populations dispersed over the continent is currently unknown.

Based on genetic evidence, it appears that the two species first interacted when Homo sapiens started sometime venturing outside of Africa around 250,000 years ago.

"We can only surmise what Homo sapiens might have thought of their cousins since we don't know exactly how Neanderthals appeared or acted," Chris explains.

Given the length of the gap in time, the linguistic disparities "would presumably have been more than we could anticipate and would have been substantially larger than those between any present languages."

When comparing Neanderthal and Homo sapiens, it has been suggested that the species' vocal organs and brains may have been different, contributing to the language barrier.

Genetic Shifts

The genomes of Neanderthals also reveal that over 600 genes, notably those connected to the voice and face, were expressed differently between our species and theirs.

The forehead would have been another noticeable change, as Neanderthals had a distinct brow ridge that may have been employed for social communication.

However, it's possible that our predecessors didn't understand the messages that these ridges were attempting to send. According to several research, Homo sapiens were able to use their eyebrows to communicate a variety of finer, transient messages because they had fewer brow ridges.

These interactions eventually resulted in mating between both species, but it is unclear exactly how this happened.

Related Article: Neanderthals Are First Humans to Greatly Influence Their Prehistoric Environment 

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