Neanderthal Extinction Was Caused by Inbreeding and Demographic Shifts: Study
Wed, April 21, 2021

Neanderthal Extinction Was Caused by Inbreeding and Demographic Shifts: Study

Neanderthals, who lived throughout Europe and several parts of Asia from about 400,000 until 40,000 years ago, are an extinct species of hominids that were the closest relatives to modern human beings / Photo by: IR Stone via Shutterstock.

 

In 1856, remnants of a skeleton were found by a group of quarrymen in the Neander Valley near Dusseldorf, Germany. Thinking that the 16 pieces of bones, including a skull, belonged to a bear, they gave them to Johan Karl Fuhlrott, a local teacher. Fuhlrott eventually gave it to scientists and it was revealed that the bones were ancient human relatives. Since then, more Neanderthal bones have been found. 

Neanderthals, who lived throughout Europe and several parts of Asia from about 400,000 until 40,000 years ago, are an extinct species of hominids that were the closest relatives to modern human beings. They originated in Africa, just like other humans, but migrated to Eurasia long before other humans did. While they are the closest relatives to modern humans, their facial features were different. According to an article by the Natural History Museum, they had distinctive faces and long, low skulls. Their faces were dominated by a very big, wide nose due to their adapting to colder, drier environments.

Researchers concluded that Neanderthals were incredibly strong because of their musculature marks. Their fossils also suggested that they may have endured a lot of pain. "When you look at adult Neanderthal fossils, particularly the bones of the arms and skull, you see [evidence of] fractures. I’ve yet to see an adult Neanderthal skeleton that doesn’t have at least one fracture, and in adults in their 30s, it’s common to see multiple healed fractures,” Erik Trinkaus, an anthropologist at Washington University in St. Louis, said. 

Despite their reputation as being primitive ‘cavemen’, Neanderthals were intelligent and accomplished human beings. They were skilled toolmakers as seen through the excavated objects found with their fossils, including spears and flint handaxes. They even developed an innovative stone technology called the Levallois technique around 300,000 years ago. It involved making pre-shaped stone cores that could be finessed into a finished tool at a later time. These early humans were also proficient hunters and able to communicate. 

Neanderthal Extinction: Theories

Compared to other ancient humans, the Neanderthal’s appearance was the closest to ours. The only difference is that they were stockier with angled cheekbones, shorter, and had prominent brow ridges and wide noses. Aside from that, they exhibited several traits and behavior that are the same as modern humans. This includes using tools, burying their dead, and controlling fire. 

According to Smithsonian Mag, the official journal published by the Smithsonian Institution in Washington, D.C., Neanderthals must also have been caring. Paleoanthropologists stated that to survive disabling injury or illness requires the help of fellow clan members. “This was really the first demonstration that Neanderthals behaved in what we think of as a fundamentally human way. The result was that those of us studying Neanderthals started thinking about these people in terms of their behavior and not just their anatomy,” Trinkaus said. 

However, if they were just as intelligent as us, why did they disappear? The only information that researchers were able to know is that Neanderthals went extinct in Europe around 40,000 years ago, which is roughly 5,000 to 10,000 years after meeting the first Homo Sapiens. Their extinction continues to baffle experts throughout the years. Some believed that their extinction was influenced by the changing climate. During those years, the climate on our planet grew colder, transforming much of Europe and Asia into a vast, treeless steppe.

Unfortunately, this climate might have been better suited to find food and survive the harsh, new climate to Homo Sapiens since they had a more diverse diet than Neanderthals and long-distance trade networks. Other theories suggest that modern humans violently exterminated Neanderthals when they crossed paths or modern humans brought some kind of disease with them from Africa for which Neanderthals had no immunity. 

The only information that researchers were able to know is that Neanderthals went extinct in Europe around 40,000 years ago, which is roughly 5,000 to 10,000 years after meeting the first Homo Sapiens / Photo by: gerasimov_foto_174 via Shutterstock

 

Inbreeding and Population/Demographic Shifts

It was widely believed that the Homo Sapiens dominated Europe when they arrived in Europe, where Neanderthals were living. They outsmarted the Neanderthals and outnumbered them. Previous research showed that Homo Sapiens had more competitive advantages than them, including improved hunting techniques and more diverse subsistence strategies, better clothing and shelter, social differences, and more. As a result, their extinction was driven by the arrival of modern humans. 

However, a recent study published in the open-access journal PLOS ONE by a research team led by Krist Vaesen from the Eindhoven University of Technology, the Netherlands, showed that there are other reasons for their extinction. The findings of the study revealed that the Neanderthal population was so small when modern humans arrived in Europe. Natural fluctuations in birth rates, death rates, and sex ratios as well as inbreeding could have been the reason why they no longer exist. 

“The main conclusion of our work is that humans were not needed for the Neanderthals to go extinct. It’s certainly possible that it was just bad luck,” Vaesen said. 

It was widely believed that the Homo Sapiens dominated Europe when they arrived in Europe, where Neanderthals were living. They outsmarted the Neanderthals and outnumbered them / Photo by: Pikoso.kz via Shutterstock

 

According to Phys.org, an internet news portal that provides the latest news on science, the researchers developed population models for simulated Neanderthal populations of various initial sizes using the data from extant hunter-gatherer populations as parameters. They used the model to see if factors like inbreeding, annual random demographic fluctuations in births, deaths, and the sex ratio, and Allee effects could bring about an extinction event. 

The researchers discovered that the three distinct factors that led to their extinction include inbreeding, which harms the fitness of the population; Allee effects, where small populations fail to grow because of limited mate choice, and natural fluctuations in birth rates, deaths and sex ratios. “It has nothing to do with competition or superiority, it’s more of a fragmentation of the habitat,” Vaesen said.

This study sheds light on the mystery surrounding the extinction of the Neanderthals. The findings can be used in further studying how they lived thousands of years ago.