Insights into how Sapiens contributed to Neanderthal extinction

Neanderthals Illustration by AI

Around 37,000 years back, Neanderthals came together in small groups in present-day southern Spain. This happened after the eruption of the Phlegraean Fields in Italy just a few thousand years earlier, which totally messed up the food chain throughout the Mediterranean. Following extensive research, it appears that a combination of factors such as internal competition, inbreeding, and interactions with Homo sapiens all played a role in the extinction of this species from the planet.

A scientific article in Live Science reports that their day-to-day routine involved crafting tools from stone, munching on birds and fungi, etching symbols into rocks, and fashioning jewelry out of feathers and shells.

They never knew they were the last of their kind, but the extinction of Neanderthals actually started tens of thousands of years before their disappearance. They became isolated and scattered, eventually leading to the end of their existence in parts of Eurasia after nearly half a million years of existence.

By around 34,000 years ago, our closest relatives had vanished. Since Sapiens and Neanderthals coexisted for thousands of years, experts have pondered whether our species played a part in their extinction. This could have been through direct means like violence or indirectly through disease and competition for resources.

Now, scientists are piecing together the puzzle of how the Neanderthals met their end, and the possible involvement of our species in their fate.

Shara Bailey, a biological anthropologist at New York University, explained to Live Science that we have a pretty good idea of what happened to the Neanderthals, and it’s a complex situation. After years of research, it seems that a mix of factors like internal competition, inbreeding, and encounters with our own species (us, Homo sapiens) all contributed to their disappearance from Earth.

The rise and demise of the Neanderthals.

The modern story of the Neanderthals began in 1856, when miners discovered a strangely unhuman-looking skull in Germany’s Neander Valley.

Archaeologists gave the skull a new species name: Homo neanderthalensis. In the decades after the discovery, researchers assumed the creature was a knuckle-dragging brute. This depiction was based on a flawed reconstruction of an older Neanderthal skeleton, whose spine was deformed by arthritis, found at La Chapelle-aux-Saints in France.

Now, more than 150 years of archaeological and genetic evidence makes it clear that this early human relative was far more advanced than we had previously thought.

Neanderthals were pretty advanced, making fancy tools, maybe even creating art, adorning themselves, burying their dead with care, and communicating like pros (even if their language was a bit more basic than ours).

They managed to survive for ages in the tough climates of Northern Europe and Siberia. Archaeological digs show that Neanderthals and Sapiens hung out together in Europe for anywhere from 2,600 to 7,000 years, which is pretty mind-boggling. But, sadly, this friendship came to an end, leaving us wondering if Sapiens had a hand in the Neanderthals’ disappearance.

According to archaeologist Tom Higham from the University of Vienna, the story of Neanderthals’ survival and eventual extinction is all about regional differences. In some areas, it seems that Sapiens came to parts of Europe where Neanderthals were no longer living. However, in other regions, there was some overlap and evidence of interbreeding between the two groups.

The first proof of this interbreeding was discovered in 2010 when the Neanderthal genome was sequenced. Genetic analyses since then have shown that Neanderthals and modern humans not only lived in the same areas but also shared DNA. This means that every modern human population studied so far has a little bit of Neanderthal in them.

Already on the brink of extinction.

When modern humans and Neanderthals met tens of thousands of years ago, Neanderthals were likely already in trouble. Genetic studies suggest Neanderthals had lower genetic diversity, and group sizes were smaller than modern humans. That suggests a possible reason for Neanderthal extinction.

“Genetically, one big clue we have is the idea of ​​heterozygosity,” Omer Gokcumen, an evolutionary genomicist at the University at Buffalo, told Live Science.

An individual receives two copies, or alleles, of a gene from each parent. Individuals are “heterozygous” for a particular gene if they inherit a different allele from each parent.

In the small Neanderthal community, which had fewer than 20 adults in each group, there was more inbreeding. That meant fewer people inherited different versions of a gene from each parent and, therefore, had lower heterozygosity.

“Neanderthals probably suffered from that, what’s called mutational load,” Gokcumen said.

Genetic research suggests that Neanderthals had a lot of problematic mutations that likely affected their survival.

“Because of their small population size, they couldn’t really breed out these bad alleles, and their children were probably really sickly in the end,” Gokcumen said.

Any animal population survives through successful reproduction and nurturing of offspring. Researchers who have estimated Neanderthal infant mortality rates have found that even a 1.5% drop in infant survival could have resulted in the population going extinct within 2,000 years, April Nowell, a Paleolithic archaeologist at the University of Victoria in British Columbia, told Live Science.

“It doesn’t take much to really have a dramatic impact on the viability of your population,” Nowell said.

So while Neanderthal populations were beginning to decline into small, isolated groups without the social support needed to care for their increasingly sickly babies, groups of modern humans were rapidly spreading across Europe.