Death of the Neanderthals may have been a result of INBREEDING and not competition with of modern humans, scientists claim
- Neanderthals practised interbreeding and kept to small population groups
- Researchers say this could have led to their eventual demise 40,000 years ago
- The study says their demise may have been down to a ‘stroke of bad luck’
Inbreeding and small population groups could have led to the extinction of Neanderthals – not just the arrival of modern humans – research suggests.
Neanderthals disappeared around 40,000 years ago, about the same time anatomically modern humans started migrating to the Near East and Europe.
Unlike other studies into the demise of the Neanderthal, new research by Eindhoven University of Technology in the Netherlands suggests humans may not be at fault – at least not entirely at fault.
‘The species’ demise might have been due merely to a stroke of bad, demographic luck’, say researchers.
Neanderthals disappeared around 40,000 years ago, about the same time anatomically modern humans started migrating to the Near East and Europe
It has long been thought the replacement of Neanderthals by modern humans was due to environmental pressure or a superiority of modern humans with respect to competition for resources.
The new study published in the PLOS One journal suggests these factors may not be entirely responsible for the demise of the ancient human relatives.
‘Our study suggests that any plausible explanation of the demise also needs to incorporate demographic factors as key variables’, says Krist Vaesen from the team.
Researchers used data from studies carried out on currently living hunter-gatherer populations and applied that to a simulation of Neanderthal populations of various different sizes to create a population model.
They then added variables for inbreeding, reduced population size – known as the Allee effect, annual random demographic fluctuations and the sex ratio.
They did this to see if these factors could bring about an extinction event over a 10,000-year period without any other input.
It has long been thought the replacement of Neanderthals by modern humans was due to environmental pressure or a superiority of modern humans with respect to competition for resources
According to the findings, inbreeding alone was unlikely to have led to extinction.
However, reproduction-related Allee effects where 25% or fewer Neanderthal females gave birth within a given year, could have caused extinction in populations of up to 1,000 individuals.
Researchers suggest that together with demographic changes, Allee effects plus inbreeding could have caused extinction within 10,000 years.
Researchers used data from studies carried out on currently living hunter-gatherer populations and applied that to a simulation of Neanderthal populations of various different sizes
But the scientists acknowledge their population models are limited by their parameters, which are based on modern human hunter-gatherers and exclude the impact of the Allee effect on survival rates.
They add it is possible modern humans could have impacted Neanderthal populations in ways that reinforced inbreeding and Allee effects – something which is not reflected in the models.
However, by showing demographic issues alone could have led to Neanderthal extinction, the researchers note these models may serve as a “null hypothesis” for future competing theories.
WHO WERE THE NEANDERTHALS?
The Neanderthals were a close human ancestor that mysteriously died out around 50,000 years ago.
The species lived in Africa with early humans for hundreds of millennia before moving across to Europe around 500,000 years ago.
They were later joined by humans taking the same journey some time in the past 100,000 years.
The Neanderthals were a cousin species of humans but not a direct ancestor – the two species split from a common ancestor – that perished around 50,000 years ago. Pictured is a Neanderthal museum exhibit
These were the original ‘cavemen’, historically thought to be dim-witted and brutish compared to modern humans.
In recent years though, and especially over the last decade, it has become increasingly apparent we’ve been selling Neanderthals short.
A growing body of evidence points to a more sophisticated and multi-talented kind of ‘caveman’ than anyone thought possible.
It now seems likely that Neanderthals buried their dead with the concept of an afterlife in mind.
Additionally, their diets and behaviour were surprisingly flexible.
They used body art such as pigments and beads, and they were the very first artists, with Neanderthal cave art (and symbolism) in Spain apparently predating the earliest modern human art by some 20,000 years.