Scientists are close to solving the mystery of the mass extinction: why the Neanderthals died out.
Neanderthals are our closest prehistoric relatives. But about 40,000 years ago, the last of them mysteriously disappeared.
Now, a recent study that analyzed the DNA of one of the last of these ancient humans is giving scientists a clue as to why they disappeared when modern humans they are succeeding.
The mystery surrounding one of the last Neanderthals
Ludovic Slimak holds Neanderthal teeth. MATTHIEU RONDEL/Getty Images
Tens of thousands of years ago, a Neanderthal named Thorin lived in southeastern France, shortly before his species went extinct.
His remains they were first discovered in 2015 and sparked a debate between archaeologists, who dated it between 50,000 and 42,000 years old, and geneticists, who insisted that his DNA showed that he was close to 100,000 years old.
The discrepancy sparked a seven-year investigation, which culminated in a recent study in which geneticists looked at the DNA of several Neanderthals from around the world and compared them to of Thorin, starting with the assumption that he was 50,000 years old instead of 100,000.
“At this time, geneticists decided to measure their tools and change everything we know about the Neanderthals,” archaeologist Ludovic Slimak, lead author of a new study published in Cell Genomics, told Business Insider. Namely, that they were all part of one homogenous population.
Because of how different his DNA was from Neanderthals around his age, the researchers realized that Thorin must have belonged to a new Neanderthal lineage. They estimate that his ancestral lineage split about 103,000 years ago.
This explained why Thorin’s DNA appeared to be much older than his bones. His DNA is similar to Neanderthals who lived more than 100,000 years ago, but Thorin was 50,000 years younger, according to recent research.
What would cause genes to diverge? Researchers suspect that Thorin lived in an isolated area that had no contact with other groups from the time they defected until Thorin’s death.
It means that, the people inside the a nation was born among them for more than 50,000 years, creating a unique lineage that differs from other Neanderthal groups, according to the researchers.
As you can imagine, a society that has been isolated for such a long time is bound to breed bonds, and the researchers actually found evidence of that in Thorin’s DNA.
Isolation also helps explain why Thorin was one of the last of the Neanderthals. Reproduction leads to the need for geneswhich can make the population more vulnerable to disease, harmful genetic mutations and environmental changes.
Although a single isolated population cannot account for all species, it can point to key behaviors that shed new light on why their human relatives dead.
“We have this incredible destruction, the last great destruction of humanity,” Slimak said.
Neanderthals were self-preserving, which may help explain their extinction
The Neanderthal bone park at The Smithsonian Museum of Natural History shows how the body of this species has changed over thousands of years. Bill O’Leary/The Washington Post via Getty Images
Thorin’s community was not divided by geography. They were excluded because they chose to be, Slimak said. “We are facing a limit, a social limit,” he said.
Actually, Other Neanderthals lived within a few weeks of Thorin’s in the Massif Central at the same time.
If Thorin’s relatives ignored their Neanderthal neighbors, it means that the group’s isolation was not only genetic but also cultural and social, Slimak said.
“It is very important and very important to understand what these inhabitants were and, finally, how they disappeared and how they died,” said Slimak.
Although isolation may have worked for Thorins ancestors for thousands of years, their luck eventually ran out. “Their little social network shut itself down and died a whisper,” Slimak said.
The large webs of modern humans may have helped them survive
An exhibit showing the life of a Neanderthal family in a cave at the Neanderthal Museum in Krapina, Croatia. Reuters/Nikola Solic
How widespread this isolation behavior was among Neanderthals is unclear. If the resources in the area were scarce, the Neanderthals would have started to have more ways to protect their group.
“Maybe this idea of one group preserving itself is probably not crazy in that kind of competitive environment,” said April Nowell, a Paleolithic archaeologist at the University of Victoria who was not involved in the study.
As the numbers of Neanderthals dwindled, keeping smaller and smaller groups would jeopardize their future whenever a family member died.
Many experts believe that small groups of Neanderthals led to their extinction, which would have made them vulnerable even without additional stress such as increased competition from humans.
Meanwhile, it seemed that modern people did not have the same tendency to create independent nations. Instead, they have traveled far and wide and created a large social network, Slimak said.
“We see modern humans who appear to have extensive social networks and exchange genes with potential mates over a wide area,” Nowell said.
Modern human groups were growing and becoming more genetically diverse. That made them better equipped to deal with any kind of accident or natural disaster, Nowell said.
On the other hand, with a small Neanderthal population, even the loss of a few individuals of reproductive age affects future generations, he said.
“I really think the isolation tells us something interesting about the Neanderthals and their challenges and eventual extinction,” Nowell said.