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Did Modern Humans—Not Environmental Catastrophe—Extinguish the Neandertals?

The views expressed are those of the author and are not necessarily those of Scientific American.

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Reconstruction of a male Neandertal from the Neanderthal Museum in Mettmann, Germany. Image: Ökologix, via Wikimedia Commons

The stocky, heavy-browed Neandertals ruled Europe for hundreds of thousands of years. And then, around 40,000 years ago, their population began to decline sharply; shortly after 28,000 years ago or so they were gone. In their place stood anatomically modern humans. Did the Neandertals die at the hands of the invading moderns? Did the moderns outcompete them? Or was catastrophic environmental change the culprit? Researchers have debated the nature of the Neandertals’ mysterious demise for decades.

In recent years scenarios implicating rapid swings in climate and/or a massive volcanic eruption in southern Italy some 40,000 years ago that ostensibly led to a volcanic winter have gained prominence. The idea is that these disastrous events pushed Neandertals out of vast areas of Europe, opening up these territories to moderns, or that the events fostered adaptive changes among moderns that enabled them to overtake the resident Neandertals. But a new study casts doubt on those environmental explanations and blames the downfall of our closest evolutionary cousins on modern humans instead.

John Lowe of the Royal Holloway University of London and his colleagues set out to test the theory that environmental change precipitated the decline of the Neandertals 40,000 years ago. They located microscopic layers of volcanic ash known as cryptotephra deposits from that mega eruption at a number of archaeological sites–including ones located well north and south of the Mediterranean–containing Neandertal and modern human remains. Having evidence of this well-dated event in all these places allowed the team to synchronize the archaeological and paleoclimatic records from the sites, eliminating some of the dating uncertainties that can hinder studies of cultural responses to environmental change.

The researchers studied the record of Neandertal and early modern human artifacts underlying (and thus predating) and overlying (and thus postdating) the ash from the Italian eruption, which occurred just after the start of a brutally cold and dry climate phase. They found that the transition to the more advanced technologies of the so-called Upper Paleolithic cultural traditions associated with modern humans began before the eruption. This indicated to the team that neither that blast nor the concurrent climate deterioration drove the cultural changes, the dispersals of moderns, or the regional extinction of Neandertals in northern and eastern Europe during this time, and that Neandertals were probably mostly gone long from these places before then. (The Neandertals managed to hang on in Iberia and possibly elsewhere for thousands of years longer though.)

“Our evidence indicates that, on a continental scale, modern humans were a greater competitive threat to indigenous populations than the largest known volcanic eruption in Europe, even if combined with the deleterious effects of climatic cooling,” Lowe and his colleagues conclude in the report detailing their findings, published online this week by the Proceedings of the National Academy of Sciences USA. “We propose that small population numbers and high mobility may have initially saved the Neandertals, but that they were ultimately outperformed in this capacity by [anatomically modern humans].”

When I read this paper, I wondered what Clive Finlayson of the Gibraltar Museum would have to say about it. Finlayson has been a leading proponent of the theory that climate change was the main cause of the Neandertals’ demise, which I wrote about in 2009. I emailed him asking he thought about the new study and he had this to say:

“Since the Neanderthals were extinct in the region at the time of the eruption it is clear that it was not a cause, neither was the subsequent climate change. That’s fine. But it does not mean that the conclusions which the authors come to from this are any closer to what may have occurred, for the following reasons:

1) The Neanderthal extinction was not a punctual event but a long drawn process, as I have often explained and written about, of attrition of population levels with partial recoveries along the way.

2) The authors claim that “modern human” presence before and after the eruption shows they were unaffected by the event. Not necessarily because all they have is presence. We have no idea of population levels before and after. We don’t know either if those that show up after might have come in from a distant region to fill a vacuum. We just cannot say.

3) The authors claim evidence of competition from modern humans as the cause of the Neanderthal extinction. This is the default argument – we think we didn’t find evidence of climate or volcanic activity on the Neanderthal extinction, therefore it must have been modern people. Why? Show it!

4) That this event and its aftermath did not cause the Neanderthal extinction – which is hardly surprising given 1) above – does not mean that other climatic and environmental changes did not!”

Finlayson was not previously convinced that the eruption did in the Neandertals, and obviously he’s not persuaded that the authors of the new study have eliminated climate change as the cause.

If Lowe and his colleagues are right, however, and competition with modern humans was what doomed the Neandertals, it’s going to be really interesting to see if paleoanthropologists can home in on what gave them that competitive advantage. Once upon a time Neandertals were seen as brutes who could barely find their way out of their caves. But then archaeologists started finding evidence of Neandertal sophistication—a piece of jewelry here, a fancy tool there. Discoveries made over the past few years have further blurred the divide between Neandertals and modern humans. Sequencing of ancient DNA has shown that Neandertals interbred with early modern humans—often enough that up to 4 percent of the DNA in people outside Africa today comes from Neandertals. More recently researchers have shown that Neandertals used medicinal plants and might have made cave art.

Man oh man what I wouldn’t give to journey back to the last glacial stage to see how it all went down. In a climate-controlled, volcanic eruption-proof time machine, of course.




Kate Wong About the Author: Kate Wong is an editor and writer at Scientific American covering paleontology, archaeology and life sciences. Follow on Twitter @katewong.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Sauce23 12:16 pm 07/24/2012

    I love this piece. Pulling together new reports, past observations, and wonderment about science as a cohesive professional presentation takes special talent. I closed my eyes and shared the same thoughts about Kate’s closing paragraph.

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  2. 2. LordDraqo 1:41 pm 07/24/2012

    My personal take is that Neandertal did not “die out,” but rather interbred with Cro Magnon to produce what we think of as “modern” man, and that there are sometimes “throwbacks” to the earlier genetic strains that appear in our society.

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  3. 3. mekhan 2:11 pm 07/24/2012

    Excellent piece. When I read the headline, I thought immediately of Finlayson and wondered what his take on the study would be. Good to read his comments. Thanks, Kate.

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  4. 4. JMFranklin 2:29 pm 07/24/2012

    Good article Kate, and nice to see the results of following it up with an alternative opinion, good to see that some journalists can actually do the job properly.

    What I don’t get is why some researchers have to have one answer or another, pot or kettle so to speak. Nature very rarely works in absolutes, especially when we discuss an extinction event.

    For too long people have spoken of Neanderthals in isolation, but the simple truth is that they were not the only creature to go the way of the Dodo in the same time period. Are we to assume that Homo Sapiens did them all in??

    It is highly probable that Homo Sapiens, why on earth do they say “modern humans” when we have been around for well over 100,000 years, probably longer, interacted with Neanderthals in every way we interact with our own kind, namely, sex, peaceful co-operation and war. On top of this it is highly probable that environmental changes, not just climate change, may have pushed groups of both Homo Sapiens and Neanderthals to extinction, in the end, Homo Sapiens had greater numbers and a supply of “blood” outside the effected region.

    When food became scarce, it is highly likely that both groups fought for survival, the greater numbers of Homo Sapiens would have benefited them, and the rest, as the3y say, is history.

    Nature is not “black and white”, and I am sure the demise of any of the species of hominid that have existed in the last couple of million years had multiple causes, any of which alone would not have been enough, but when coupled to simultaneous pressures, the writing was on the wall.

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  5. 5. 2:33 pm 07/24/2012

    I’d think that the climate change contributed to the Neanderthal demise: they were a bit bigger and more muscular (from my understanding), so they’d need more sustenance than the early humans. It’d be harder for them to thrive on lower calorie intake, slowly helping early humans to take over.

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  6. 6. jtdwyer 3:02 pm 07/24/2012

    As ‘LordDraqo’ suggests, doesn’t the degree to which the modern human genome now incorporates Neanderthal genes indicate some degree to which they were integrated into modern human populations? Surely this should have been worthy of some mention…

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  7. 7. kwong 3:33 pm 07/24/2012

    Sauce23 and mekhan: Thanks!

    LordDraqo and jtdwyer: I do note in the post that DNA studies have shown that Neandertals and early modern humans interbred, and that people today carry Neandertal DNA. Neandertals as a distinctive human group died out but their DNA lives on in us. Yes–paleoanthropologist Leslie Aiello made this point to me several years ago when I wrote a long article on Neandertals. She called them “the SUVs of the hominid world.”

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  8. 8. WalterG 4:15 pm 07/24/2012

    Please check this article, it is far more elaborate. Most humans today are around 5% neanderthal.

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  9. 9. VIP 5:48 pm 07/24/2012

    Did Modern Humans Extinguish the Neandertals?
    Definitely not, we saved them to be politicians.

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  10. 10. jtdwyer 10:10 pm 07/24/2012

    kwong – Sorry I missed your mention of interbreeding. With the successful integration of Neanderthals into the human genome, how can they be considered to have been ‘wiped out’, except as a distinct group?

    In that same context, how many genetically differentiated populations have become genetically indistinct within the genome of modern humans prior to their becoming genetically distinct groups of humans? Isn’t the process the same, simply a matter of the duration of genetic isolation? In the current conditions of global population and geographical interaction, there’s little possibility that human distinct subgroups can develop. Even modern humans can’t claim to have avoided being ‘wiped out’…

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  11. 11. blindboy 6:10 am 07/25/2012

    I always believed that a principle of ecology stated that when two species were in direct competition for a key resource the most likely outcome was the extinction of one of the two. If that is correct then competition with H. sapiens sapiens should be the default explanation in the absence of conclusive evidence to the contrary.
    This does not imply genocidal behaviour, only that for, whatever reason, H. sapiens sapiens was better adapted to the prevailing environment.

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  12. 12. jack.123 5:55 pm 07/25/2012

    I think viral and bacterial infections brought by modern humans is a more likely explanation.Look at what happened to North American tribes with the introduction of small pox.

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  13. 13. Donzzz 9:10 pm 07/25/2012

    Why did the other Hominids (Neanderthals and Homo Erectus) become extinct while the “Homo Imaginative Sapiens” survived and prospered?

    The answer is – The earlier hominids and the archaic non-imaginative Homo Sapiens (the modern humans before they became imaginative) did not have the one trait that made the difference in their survival. Our distant cousins (Homo Erectus, Neanderthals, etc.) were able to survive for long periods of time but when they encountered overwhelming conditions that they could not handle they died off and became extinct. The one condition that they could not handle was the “Homo Imaginative Sapiens” tribes who were coming out of Africa around forty to fifty thousand years ago.

    These new imaginative tribes (modern human Homo Sapiens) had lived in Africa for thousands of years after they had become imaginative, inventing languages, new tools and weapons during this time. They had multiplied and split into many new tribes over time. They became the dominant hominids in Africa wiping out the non-imaginative tribes as they settled the whole continent. The Homo Sapiens (imaginative and non-imaginative) did interbreed during this time and they all assimilated and became imaginative. Finally with the Homo erectus and Neanderthals gone the Homo Sapiens began to encounter more and more other imaginative tribes which were much harder to deal with.

    For entire article see:

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  14. 14. Andira 11:55 pm 07/25/2012

    A very fine article.

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  15. 15. Knyaz 2:23 am 07/26/2012

    Возможно эволюция происходит в информационном поле.Если поместить человека в информационное поле животных из него вырастет маугли а если в информационное поле людей то из него вырастет человек.Если этот человек в течении своего физического развития не будет интересоваться наукой то из него вырастет “неандерталец”.Если миры многомерны то возможно во время перехода из одного измерения в другое происходит преобразование в информационно -световой поток.Переход осуществляется через чёрную дыру.После появления в новом измерении информационно-светового потока начинается материализация объектов согласно информации находящейся в в этом потоке.Возможно информация о таких переходах зашифрована в транспортном РНК гена.Возможно искажонная или изменённая информация во время перехода отсеивается(судный день)поэтому попадая после перехода в другое измерение на эту планету мы оказываемся в окружении живых объектов которые по каким то причинам не смогли перейти в более высшее измерение.Извините если из-за качества перевода или по каким то другим причинам будет не всё всем понятно,я просто поделился своими мыслями.

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  16. 16. joe poppa 4:39 pm 07/26/2012

    It is my understanding, from other articles I have read, that there is a good deal of Neandertal DNA in modern humans so, the evidence is clear, we did not kill them off; we simply f***d them to death.

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  17. 17. Extremophile 3:27 am 07/30/2012

    I have no understanding why scientists try to identify a mono-causal explanation, when the world around us shows us that combinations of causes create combinations of effects.

    When Europeans invaded the Americas, they brought death to natives there in many forms: violence, diseases, destruction of habitats, alcohol, etc.

    And they brought death back home in form of Syphilis (most likely) and other diseases. And violence again, e.g. when pirates entered gold transports.

    Maybe, scientists should return to their true task – science, based on evidence – and leave the wild speculations to the rainbow press?

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  18. 18. cccampbell38 9:42 pm 07/30/2012

    Lord Drago et. al. who mentioned the mixing of the species: I have seen several people in my life, one in particular about 30 years ago, that I swear could put on skins, stand in a good diorama in the museum of natural history, and easily pass as a Neanderthal. The stature, the brow ridges, the jaw structure, the cheek bones were all much more “Neanderthal” than “Homo Sapiens”. I have never observed evidence of intellectual or social difference, no “matching the stereotype” behaviors, just a very noticeable physical difference.

    Could this possibly be the “throwback” that you mentioned?

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  19. 19. Plain-2009 2:03 am 07/31/2012

    The subject of Neanderthals is fascinating. Let us do a mental exercise. What would happen if they still existed today? I do not see the glass half empty; I see the glass half full. And I feel present day humans can live in peace with each other. And probably 100,000 years into the future we are going to mix together to the extent that there will be only one human race. But at the same time we should be realistic. We (modern day humans) have been fighting against each other all he time. If the Neanderthals existed today, would it be a peacefully coexistence with us modern humans? Could we be respectful with each other? This is what will happen the day we find other intelligent race in outer space. It seems very clear that the Neanderthals did not die out entirely. If the fact is well proved hat the people outside of Africa all have 4% or 5% of genes that came from Neanderthals, to certain extent we all are Neanderthals. So it seems the modern humans did not kill the Neanderthals, I would say. It was a natural process in which the number of Neanderthals went into decline and to a certain extent integrated into the modern humans. So we modern humans are a mixture of all the species similar to Neanderthals and Homo Sapiens that existed, in the same time period, and could interbreed. And who knows that in the future we mix with a race in the constellation of Aquarium? Of course I am just taking all the facts that I read here and doing a mental exercise. Before I finish let me tell that I couldn’t understand what our friend from Russia, with that beautiful way of writing, had to say. We need to know (and probably much is known already) in what time period did the Neanderthals lived and how they were physically and genetically. The remains of the Neanderthals should be carefully preserved.

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  20. 20. Plain-2009 2:12 am 07/31/2012

    And it seems my touch of the subject is very superficial. As I continue reading (and I do not want to waste your valuable time) may be some 95% intelligent and respectable Neanderthals still walk the Earth. Probably some of us are 5% Neanderthals, may be some of us are 15% Neanderthals, may be some 95% Neanderthals, and so on. The study of the subject matter should continue. Probably we are just scratching the surface.

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  21. 21. rugeirn 10:53 am 08/4/2012

    – The idea that any group or species “ruled Europe” at any time before the Roman Empire is unhistorical, unscientific and should never have appeared in any publication pretending to intellectual respectability, let alone this one. Species do not “rule” any biome, as the relationship of humans to rhinoviruses should amply demonstrate-unless we are willing to conclude that they rule us!

    – Any reasonably practical time machine would surely allow you to set the target date safely away from the date of the eruption!

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  22. 22. VivaLaEvolucion 3:07 am 09/5/2012

    I got my genetic test from and it says I have 3.1% Neanderthal DNA, which is higher than 98% of humans. Both of my parents got tested as well, and the funny thing is my mom had 3% Neanderthal and my dad had 2.8% neanderthal, both of which is high, but sort of weird that my percentage is higher than both of theirs. I guess with the margin of error my mom could have actually had like 3.3 % or something like that. I hope 23andme offers the ability to view your Denisovan percentage soon.

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