Neanderthal extinction hypotheses 1335645 224735194 2008-07-10T05:00:41Z Sleigh 146448 /* In popular culture */ reformat book title {{Mergefrom|Neanderthal interaction with Cro-Magnons|date=May 2008}} [[Image:Neanderthal child.jpg|thumb|220px|Reconstruction of a Neanderthal child from [[Gibraltar]] (Anthropological Institute, University of Zürich)]] Ever since their discovery, both the '''[[Neanderthals]]'''' place in the human family tree and their relation to modern Europeans have been hotly debated. At different times they have been classified as a separate species (''[[Homo neanderthalensis]]'') and as a subspecies of ''[[Homo sapiens]]'' (''Homo sapiens neanderthalensis''). The polemic endures on all academic disciplines of interest. Anthropologists advanced and still advance arguments favoring either an accelerated regional evolution of Neanderthal towards Homo Sapiens, or interbreeding with or replacement by anatomically modern humans. There is no agreement on the association of early [[Aurignacian]] culture to any specific physical human type, including figurative art found at Vogelherd.<ref>Conard, N.J. et al. (2004) Unexpectedly recent dates for human remains from Vogelherd. Nature 430, 198–201 [http://www.nature.com/nature/journal/v430/n6996/full/nature02690.html]; [http://www.urgeschichte.uni-tuebingen.de/fileadmin/downloads/Conard/vogelherdNature04.pdf]</ref> The interpretation of the [[Neanderthal Genome Project]] results so far vary from a 0.1% contribution of Neanderthal to the modern gene pool, to a genetic similarity not unlike two extant members of one referenced population in West Africa.<ref>[http://genetics.plosjournals.org/perlserv/?request=get-document&doi=10.1371%2Fjournal.pgen.0030175] Inconsistencies in Neanderthal Genomic DNA Sequences - Jeffrey D. Wall & Sung K. Kim, published October 12, 2007 at [[PLOS]] Genetics;[http://www.nature.com/nature/journal/v444/n7117/abs/nature05336.html] Analysis of one million base pairs of Neanderthal DNA - Richard E. Green et al, Nature 444, 330-336, 16 November 2006;[http://www.sciencemag.org/cgi/content/short/314/5802/1113] Sequencing and Analysis of Neanderthal Genomic DNA - James P. Noonan et al, Science 17 November 2006: Vol. 314. no. 5802, pp. 1113 - 1118</ref> The obvious anatomic differences between Neanderthal and anatomically modern humans inspired the general ''belief'' in two separate branches of the genus ''Homo'', and favored the [[single-origin hypothesis]] in that modern humans are not directly descended from the Neanderthal branch. The nature of interaction and dividing lines between 50-30 [[tya|kya]] of Neanderthal and archaic Homo Sapiens remain largely unknown,<ref>[http://www.jscarrion.com/pdf/finlayson_carrion.pdf] Rapid ecological turnover and its impact on Neanderthal and other human populations - Clive Finlayson and Jose´ S. Carrión, Trends in Ecology & Evolution, Volume 22, Issue 4 , April 2007, Pages 213-222</ref> and are uncertain afterwards. Though it has been suggested that the late Neanderthal populations survived in Southern Iberia, in general this area has been considered a "cul-de-sac", playing a passive role in human/biological evolution.<ref>Climate forcing and Neanderthal extinction in Southern Iberia: insights from a multiproxy marine record - Francisco J. Jiménez-Espejo, Quaternary Science Reviews, Volume 26, Issues 7-8, April 2007, Pages 836-852, Elsevier Ltd</ref> There is considerable debate about whether [[Cro-Magnon]] people accelerated the demise of the Neanderthals, and many hypotheses to that extent are currently available. ==Extinction scenarios== ===Rapid extinction=== [[Jared Melendez]] has suggested a scenario of violent conflict comparable to the [[genocide]]s suffered by [[indigenous peoples]] in recent human history{{Fact|date=June 2008}}. Another possibility, paralleling colonialist history, would be a greater susceptibility to [[pathogen]]s introduced by Cro-Magnon man on the part of the Neanderthals. Although [[Jared Diamond]] and others have specifically mentioned Cro-Magnon diseases as a threat to Neanderthals, this aspect of the analogy with the contacts between [[colonialism|colonisers]] and indigenous peoples in recent history can be misleading.{{Or|date=December 2007}} The distinction arises because Cro-Magnons and Neanderthals are both believed probably to have lived a [[nomad]]ic lifestyle,<ref>{{citation|first=Tom|last =Prideaux|title=Cro-Magnon Man|publisher= Time-Life Books| year= 1979|id=ISBN 0705400557}}</ref> <ref>{{citation|last=Lewin|first=Roger|publisher=Blackwell|title=Human Evolution: An Illustrated Introduction|year=1999|id= ISBN 0632043091}} </ref> whereas in those genocides of the colonial era in which differential disease susceptibility was most significant, it resulted from the contact between colonists with a long history of agriculture and nomadic [[hunter-gatherer]] peoples.{{Or|date=December 2007}} Diamond argues that asymmetry in susceptibility to pathogens is a consequence of the difference in lifestyle, which makes it irrelevant in the context of the analogy in which he invokes it. On the other hand, many Native Americans before contact with Europeans were not nomadic, but agriculturalists ([[Mayans]], [[Iroquois]], [[Cherokee]]), and this still did not protect them from the disease epidemics brought by Europeans ([[Smallpox]]). One theory is that because they usually lacked large domesticated animal agriculture, such as cows or pigs in close contact with people ([[Zoonosis]]), they did not develop resistance to species-jumping diseases like Europeans had. (See also ''[[Guns, Germs, and Steel]]''.)<ref>[http://www.ilri.cgiar.org/ILRIPubAware/Uploaded%20Files/20048111016100.01BR_ISS_Non-ILRI_Diamond_EvolutionOfGerms(GunsGermsSteel).htm The Evolution of Germs<!-- Bot generated title -->]</ref> ===Gradual extinction=== However, these scenarios may be more drastic than is required to explain a decline of Neanderthal population over the course of some 10,000-20,000 years{{Fact|date=December 2007}}: even a slight [[natural selection|selective]] advantage on the part of modern humans could account for Neanderthals' replacement on such a timescale.{{Fact|date=December 2007}} Gradual climatic change as a cause of extinction is also a common hypothesis.{{Fact|date=December 2007}} Speech-related theories have been largely discredited.{{Fact|date=February 2007}} The problem with a gradual extinction scenario lies in the resolution of dating methods.{{Or|date=December 2007}} There have been claims for young Neanderthal sites, younger than 30,000 years old.<ref>Finlayson, C., F. G. Pacheco, J. Rodriguez-Vidal, D. A. Fa, J. M. G. Lopez, A. S. Perez, G. Finlayson, E. Allue, J. B. Preysler, I. Caceres, J. S. Carrion, Y. F. Jalvo, C. P. Gleed-Owen, F. J. J. Espejo, P. Lopez, J. A. L. Saez, J. A. R. Cantal, A. S. Marco, F. G. Guzman, K. Brown, N. Fuentes, C. A. Valarino, A. Villalpando, C. B. Stringer, F. M. Ruiz, and T. Sakamoto. 2006. Late survival of Neanderthals at the southernmost extreme of Europe. ''Nature'' advanced online publication.</ref> Even claims for interstratification of Neanderthal and modern human remains have been advanced.<ref>Gravina, B., P. Mellars, and C. B. Ramsey. 2005. Radiocarbon dating of interstratified Neanderthal and early modern human occupations at the Chatelperronian type-site. ''Nature'' 438:51-56.</ref> So the fact that Neanderthals and modern humans coexisted at least for some time seems certain. However, because of difficulties in calibrating the C14 dates the duration of this period is uncertain.<ref>Mellars, P. 2006. A new radiocarbon revolution and the dispersal of modern humans in Eurasia. ''Nature' 439:931-935.</ref> ===Interbreeding=== {{main|hybrid-origin|Neanderthal Genome Project}} There is another hypothesis that the Neanderthals were absorbed into the Cro-Magnon population by [[Hybrid (biology)|interbreeding]]. This scenario would render the [[Recent African Origin]] scenario obsolete in favour of a ''[[hybrid-origin]]'' scenario, since it would imply that at least a minor fraction of the genome of [[European ethnic groups|Europeans]] would descend from Neanderthals, who had left Africa at least 350,000 years ago. No evidence supporting this scenario has been found in mtDNA analysis of modern Europeans, suggesting at least that no direct maternal line originating with Neanderthals has survived into modern times.<ref>Krings et al., ''Neandertal DNA sequences and the origin of modern humans'' Cell. 1997 Jul 11;90(1):19-30. Deborah Hill, [http://www.ncbi.nlm.nih.gov/sites/entrez?db=PubMed&cmd=Retrieve&list_uids=9230299]; [http://sciencenow.sciencemag.org/cgi/content/full/2004/316/2 No Neandertals in the Gene Pool], Science (2004).</ref> The most vocal proponent of the hybridization hypothesis is [[Erik Trinkaus]] of [[Washington University]].<ref>Dan Jones: ''The Neanderthal within.'', [[New Scientist]] 193.2007, H. 2593 (3 March), 28–32. [http://news.yahoo.com/s/hsn/20061030/hl_hsn/modernhumansneanderthalsmayhaveinterbred Modern Humans, Neanderthals May Have Interbred]; [http://www.cosmosmagazine.com/node/814 Humans and Neanderthals interbred]</ref> Trinkaus claims various fossils as hybrid individuals, including the "child of Lagar Velho", a skeleton found at [[Lagar Velho]] in [[Portugal]] dated to about 24,000 years ago.<ref>[http://www.talkorigins.org/faqs/homs/lagarvelho.html]; [http://www.guardian.co.uk/science/story/0,,1871842,00.html]; [http://johnhawks.net/weblog/reviews/neandertals/gorhams_28000_date_2006.html]</ref> In a 2006 publication co-authored by Trinkaus, the fossils found in 1952 in the cave of Pestera Muierii, Romania, are likewise claimed as hybrids.<ref>Andrei Soficaru u.&nbsp;a.: ''[http://www.pnas.org/cgi/content/abstract/0608443103v1 Early modern humans from Pestera Muierii, Baia de Fier, Romania.]'' in: ''Proceedings of the National Academy of Sciences.'' Washington 2006.</ref> Based on an Oxford University 2001 study of the gene that results in red-headedness,<ref>[http://www.dhamurian.org.au/anthropology/neanderthal1.html Red hair a legacy of Neanderthal man<!-- Bot generated title -->]</ref> some commentators speculated that Neanderthals had [[red hair]] and that some red-headed and freckled humans today share some heritage with Neanderthals.<ref>{{cite web|url=http://www.gktgazette.com/2001/may/news.asp#red|title=Red-Heads and Neanderthals|date=May 2001|accessdate=2005-10-28}}</ref><ref>{{cite web|url=http://www.arts.telegraph.co.uk/connected/main.jhtml?xml=/connected/2002/10/04/ecfhair04.xml&sSheet=/connected/2002/10/04/ixconn.html|title=Nicole's hair secrets|date=[[2002-02-10]]|accessdate=2005-11-02}}</ref> A 2007 study analysing Neanderthal DNA found that some Neanderthals were indeed red-haired, but the mutation to the [[MC1R]] gene which caused red hair in Neanderthals was different from that found in modern individuals, possibly ruling out that red hair is a trait inherited from the Neanderthals.<ref>Paul Rincon, [http://news.bbc.co.uk/2/hi/science/nature/7062415.stm Neanderthals 'were flame-haired'] BBC 25 October 2007.</ref> ===Unable to adapt=== {{Original research|date=November 2007}} [[Image:Ice Age Temperature.png|right|thumb|300px|Graph showing the pattern of temperature and ice volume changes associated with recent glacials and interglacials]] European populations of ''H. neanderthalensis'' have been traditionally thought to be adapted to a cold environment, and thus may have had problems adapting to a warming environment.{{Or|date=December 2007}} This may or may not be the case, although it has been suggested that the difference in cold-adaptation between Neanderthals and ''H. sapiens'' may have been minor.{{Fact|date=December 2007}} Another problem with this idea is that the glacial period of our [[ice age]] ended about 10,000 years ago, while the Neanderthals went extinct about 24,000 years ago.{{Syn|date=December 2007}} Another possibility has to do with the loss of the Neanderthal's primary hunting territory - forests.{{Or|date=December 2007}} The Neanderthals hunted by stabbing their prey with spears (as opposed to throwing the spears at their prey).{{Fact|date=December 2007}} They were also far less mobile than modern humans.{{Fact|date=February 2007}} Thus when the forests were gradually replaced by flat lands, the Neanderthals would have had great difficulty hunting.{{Or|date=December 2007}} In the open they would not have been able to stalk their prey, their stabbing weapons would have been largely useless, and they - unlike modern humans - could not easily chase their prey. The heavily-set build of the Neanderthals also suggests that they may have had large energy requirements, therefore if their method of hunting became less efficient (as described above) the increased energy expenditure may have been too much to sustain.{{Or|date=December 2007}} ===Division of labor=== In 2006, anthropologists [[Steven L. Kuhn]] and [[Mary C. Stiner]] of the [[University of Arizona]] proposed a new explanation for the demise of the Neanderthals.<ref>Nicholas Wade, [http://www.nytimes.com/2006/12/05/science/05nean.html "Neanderthal Women Joined Men in the Hunt"], from ''[[The New York Times]]'', December 5, 2006</ref> In an article titled "What's a Mother to Do? The Division of Labor among Neanderthals and Modern Humans in Eurasia",<ref>Steven L. Kuhn and Mary C. Stiner, [http://www.journals.uchicago.edu/doi/abs/10.1086/507197 "What's a Mother to Do? The Division of Labor among Neandertals and Modern Humans in Eurasia"], ''Current Anthropology'', Volume 47, Number 6, December 2006</ref> they theorise that Neanderthals like [[Paleolithic#society|Middle paleolithic Homo sapiens]] did not have a [[Division of labour|division of labor]] between the sexes. Both male and female Neanderthals participated in the single main occupation of hunting big game that flourished in Europe in the ice age like bison, deer, gazelles and wild horses. This contrasted with humans who were better able to use the resources of the environment because of a division of labor with the women going after small game and gathering plant foods. In addition because big game hunting was so dangerous this made humans, at least males, more resilient (see also Peter Frost's theory on the [[Blond|origins of European blond hair]]). ===Anatomical differences and running ability=== Researches including Karen L. Steudel of the University of Wisconsin have proposed that because Neanderthals had limbs that were shorter and stockier than modern humans, and because of anatomical differences in their limbs, it is theorized that the primary reason the Neanderthals were not able to survive is related to the fact that they could not run as fast as modern humans, and they would require 30% more energy than modern humans would for running or walking. [http://www.zoology.wisc.edu/faculty/Ste/Ste.html] This would have given modern humans a huge advantage in battle. Other researchers, like Yoel Rak, from Tel-Aviv University, Israel have noted that the fossil records show that Neanderthals pelvises in comparison to modern human pelvises would have made it much harder for Neanderthals to absorb shock and to bounce off from one step to the next, giving modern humans another advantage over Neanderthals in running and walking ability. [http://www.newscientist.com/article/mg13017664.500-science-neanderthals-puzzle-the-anthropologists-.html] ===Neanderthals failed to adapt to the [[Ice Age]]=== According to this hypothesis the inability to adapt to climate change led to the Neandertals' demise.<ref>[http://news.nationalgeographic.com/news/2004/02/0209_040209_neandertals.html Climate Change Killed Neandertals, Study Says], National Geographic News</ref><ref>Gilligan, I: "Neanderthal extinction and modern human behaviour: the role of climate change and clothing", World Archaeology, Vol. 39, No. 4. (2007), pp. 499-514.</ref> Not the cold, since both Cro Magnons and Neandertals had clothing, but failure to adapt their hunting methods caused their extinction when Europe changed into a sparsely vegetated steppe and half desert during the last Ice Age. ==In popular culture== *[[Jean M. Auel]]'s book ''[[The Clan of the Cave Bear]]'', and to some extent other books in the series [[Earth's Children]], fictionally explore the lives and cultures of Neanderthals and Cro-magnons co-existing in [[Europe]]. *The fantasy novelist [[Jack Vance]], in his [[Lyonesse Trilogy]], mentions that cannibal Neanderthals battled with the ancient ancestors of the Ska, an imaginary culture or subspecies of Homo sapiens. *Science fiction novelist [[Larry Niven]] speculates that encounters with Neanderthals was the basis for human folklore about [[trolls]], [[ogres]], and suchlike. *[[Michael Crichton]]'s novel, ''[[Next (novel)|Next]]'' contains a series of articles describing the extinction of the apparently more intelligent Neanderthals with comparison with Homo sapiens. *[[William Golding]]'s second novel, [[The Inheritors (William Golding)|''The Inheritors'']] reconstructs the life of Neanderthal interaction and subsequent extinction with a "newly-evolved" malevolent Homo sapiens species. *The novel ''[[Dance of the Tiger]]'' by paleontologist [[Björn Kurtén]] explores Neanderthal and Cro-magnon integration. * The Neanderthals appear in the movie directed by [[Shawn Levy]] "[[Night at the Museum]]". They are however incorrectly depicted as a species that lacked complex language, and couldn't control fire. * ''[[The Neanderthal Parallax]]'' - a trilogy of novels by [[Robert J. Sawyer]] - shows the effects of the opening of a connection between two alternate Earths: the world familiar to the reader, and another where Neanderthals became the dominant, sentient hominid. The societal, spiritual and technological differences between the two worlds form the focus of the story. ==Notes== {{reflist}} ==References== <div class="references-small"> *{{cite journal|author=Serre ''et al.''|year=2004|title=No evidence of Neandertal mtDNA contribution to early modern humans|journal=PLoS Biology|volume=2|issue=3|pages=313&ndash;7|pmid=15024415|doi=10.1371/journal.pbio.0020057}} *http://www.ufoarea.com/evolution_bones.html </div> == See also == * [[List of fossil sites]] ''(with link directory)'' * [[List of hominina fossils|List of hominina (hominid) fossils]] ''(with images)'' * [[Neanderthal]] * [[Neanderthal interaction with Cro-Magnons]] * [[Neanderthal Genome Project]] ==External links== * [http://www.eva.mpg.de/ Max Planck Institute for Evolutionary Anthropology] * [http://neurophilosophy.wordpress.com/2006/11/08/neanderthals-humans-may-have-interbred/ Neanderthals & Humans may have interbred] * [http://www.aulis.com/twothirds2.htm The Way We Are] [[Category:Human evolution]] [[Category:Stone Age]] [[Category:European archaeology]] [[Category:Pleistocene extinctions]] [[Category:Recent single origin hypothesis]]