Neanderthals and Modern Humans

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1.  Introduction

The Neanderthals are extinct hominids who inhabited Europe and western Asia circa 300,000 to 30,000 years ago. During this time they co-existed with modern humans. The issue of whether Neanderthal populations, circa 35,000 BP, interbred with and/or were acculturated by anatomically modern humans, or became extinct in isolation, is still a matter of controversy and debate. The transition from the Middle to Upper Palaeolithic in Europe occurred some 40 to 30,000 years ago, and saw the extinction of the Neanderthals and appearance of anatomically modern humans (AMH). Three basic hypotheses have been postulated to explain the fate of the Neanderthals: (1) Neanderthals were transformed in to modern Europeans, and thus direct ancestors of modern Europeans; (2) anatomically modern humans from the Near East completely displaced the Neanderthals who contributed nothing to the AMH gene pool; (3) partial admixture took place in the expansion of AMH from Asia and thus contributed some genes to AMH. (Trinkaus, 1993; Stringer, 1993). General support, based on molecular genetic variation analysis, is usually given to the second view – the Neanderthals constituting a separate species that went extinct without contributing genes to modern humans. (Cann, 1987; Vigilant, 1991; Hammer, 1995).  The transition from the Middle to Upper Palaeolithic in Europe occurred some 40 to 30,000 years ago, and saw the extinction of the Neanderthals and appearance of anatomically modern humans (AMH). The AMH moved fairly rapidly into western Europe and may have encountered and possibly pre-existed with Neanderthals populations in some areas.

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Approximate chronological arrangement of late Pleistocene fossil types in Eurasia and Africa.  Source: Klein (1999).

2.  The Middle to Upper Palaeolithic Transition

The phenomenon known as the Middle to Upper Palaeolithic Transition, which some refer to as the Upper Palaeolithic Revolution or Creative Explosion (Lewis-Williams, 2002), occurred in western Europe between 45 and 35,000 years ago. During this time Europe had a colder climate that peaked 35,000 years ago when the Neanderthals had survived previous periods of climatic instability. During the transition England, Ireland, Scandinavia and Germany were covered by vast sheets of ice and separate ice-caps covered the Pyrenees and Alps. This ice age peaked 18 to 20,000 years ago, long after the inception of the transition. South of the ice sheets the environment consisted of tundra and steppe with a treeless landscape and frozen subsoil.

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Genealogy of modern humans and their evolutionary predecessors.  Source. public domain (Time).

The transition was the period when Neanderthals gave way to modern humans or Homo sapiens populations (Gamble, 1909; Stringer & Gamble, 1993), with “…the two forms having lived side by side, at least in some areas, for thousands of years.” (Lewis-Williams, 2002). In south-west France and northern Spain the transition occurred between 45 and 35 thousand years ago. A Neanderthal skeleton found at Saint-Cesaire in France is dated at the end of the transition circa 35,000 BP, while other remains at Arcy-sur-Cure are 34,000 BB (Hublin, 1996). At the beginning of the western European Upper Palaeolithic two distinct groups existed with different artefacts (Lewis-Williams, 2002). During the Middle to Upper Palaeolithic Transition there occurred a change in lithic technology, from flake to blade types, which was also accompanied by behavioural changes around 40 to 30,000 years ago. In western Europe the transition evidenced marked innovations that indicated changes of social of social and mental significance had occurred, changes that dated back to the start of the Aurignacian.

It was modern Homo sapiens who moved from the east into western Europe and brought with them the Aurignacian technology, art, and ideas. Compared to AMI the Neanderthals have been described as scavengers rather than hunters who lived off carnivore kills because there was no wide variety of animals which they had control over (Binford, 1981). Moreover, the Mousterian Neanderthals had operated successfully for thousands of years, in harsh European environments, with no apparent development of surviving symbolic devices (d’Errico, 1998). For a long time Neanderthals were in Europe and the Middle East, the only human types until the appearance of AMH, and the “…expansion of Neanderthals to the Near East may have been secondary, having perhaps taken place between 100 and 50 kya.” (Cavalli-Sforza, 1997). The intense debate concerning cultural and biological interactions between AMH and Neanderthals during the transition continues (Mellars, 1989; Nitecki, 1994; Graves, 1991; d’Errico, 1998).

3.  The ‘Out of Africa’ scenario

The first AMH in western Europe were the Cro-Magnon people, who were typically modern, even though they were “…continuously exposed  to potential admixture with Neanderthal. Cro-Magnon seems to emerge essentially unmixed.” (Cavalli-Sforza, 1997). It is known that archaic Neanderthals lived alongside for 30,000 years at Qafzeh in the Near East. AMH who had been there 92,000 years BP (Fagan, 1996), and further thermo-luminescence dates gave 36,000 years ago for Neanderthal artefacts in France. Despite lack of signs of admixture in most western European AMH it has been argued that, before they disappeared, Neanderthals may have established relations with AMH and hence “…may have contributed to the gene pool of modern Europeans.” (Cavalli-Sforza, 1997).    3.  Out of Africa The ‘Out of Africa’ scenario, considering the Neanderthal mtDNA sequence shows that modern humans arose in Africa as a distinct species and “…replaced Neanderthals with little or no interbreeding.” (Krings, 1997). An alternative view postulates that expanding AMH populations or groups possibly admixed with earlier types but social and cultural barriers to inter-fertility may have been more important than biological factors (Cavalli-Sforza, 1997). The debate continues concerning the nature and timing of any interactions “…between ancient modern humans and Neanderthals with…emphasis on the degree to which Neanderthals contributed genetically to the earliest modern human populations in Europe.” (Weaver, 2005).

Neanderthals and AMH lived in greater proximity in the Middle East where intermingling could have been a possibility – except the fact there is ”…no evidence Neanderthals and AMH lived at the same time: in fact in the Middle East, they are widely separated in time.” (Cavalli-Sforza, 1997). With regard to ancient DNA, the late survival of Neanderthals, and modern human-Neanderthal genetic admixture, most anthropological geneticists, human palaeontologists, and palaeological archaeologists “…now favour a predominantly extra-European origin for the earliest modern human populations in Europe.” (Weaver, 2005; see also Stringer, 2003; Trinkaus, 2003; Underhill, 2001). The analysis of diversity and global patterns points to a recent African origin of modern humans (Armour, 1996). The ‘Out of Africa’ hypothesis stipulates equal distances between all human sequences with those of Neanderthals. The distance between 300 randomly selected individuals showed for Africans 2.86, for the Mongoloids 4.06, and for Caucasoids 3.27 (Ovchinnikov, 2000).

The ‘Out of Africa’ model suggests that most extant humans can trace their ancestry to a small population of humans who originated in Africa some 200,000 years ago (Rincon, 2010). The ‘Out of Africa’ model implies that modern humans replaced the archaic Neanderthals during their migration through the Levant, the Arabian Peninsula, or north Africa. Such a group was supposedly quite small and migrated northwards out of Africa some 50,000 to 60,000 years ago.

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Migration map of the Out of Africa scenario.  Source: public domain.

4.  The Matter of Displacement and Isolation

The minimum date for the divergence of Neanderthals and modern humans has been given at 250,000 to 300,000 years ago. The mtDNA divergence date suggests 550,000 to 600,000 years ago, whereas the archaeological record indicates some 300,000 years ago. Therefore, if the evolutionary trajectories of Neanderthals and AMH separated over 500,000 years ago, then “…the possibility of such genetically based divergences in brain structure, neurology, and cognitive capacities can in no way be ruled out.” (Mellars, 1998).

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Geographical areas where fossils of Neanderthals have been found.  Source: Public domain.

Questions concern possible replacements, admixtures, and complex evolutionary phenomena, involving interaction between Neanderthals and expanding AMH (Cavalli-Sforza, 1997). Before 45,000 BP Neanderthals had the landscape alone, by 35,000 they disappeared from France, with the last Iberian outpost lasting until 27,000 BP. Some argued that localised Neanderthals evolved into AMH (Wolpoff, 1989), others that replacement occurred by migrating AMH because, after 15,000 years of interaction Neanderthalers “…were driven to extinction by the technologically and presumably socially more advanced Homo sapiens sapiens.” (Conard, 1998). Though the two groups shared a large territory, low demographic intensity, and discontinuous settlements, few biological interactions occurred with a few behavioural imitations (Hublin, 1998). If the Chatelperronian is unique then independent parallel development – ending 35,000 BP – occurred which excludes acculturation implying cultural divergence (Svoboda, 1998), indicating Neanderthals “…were the victims of us modern humans, who indisputably presided over their demise even if only as observers.” (Vega-Toscano, 1998). Interactive actuality was not violent, there being no archaeological record of fighting (Cavalli-Sforza, 1997), the incoming AMH seeking different landscapes with different hunting strategies, different social structures to Neanderthals (Gamble, 1999). The replacement hypothesis answers questions not answered by local evolution theory (Lewis-Williams, 2002), because widespread rapid migration is faster than evolutionary change by scattered, isolated, and different Mousterian populations. Replacement was not inexorable but a series of stepwise, discrete advances, and as the Neanderthal populations contracted and retreated, coexistence was not universal (Bocquet-Appel, 2000), with isolated pockets of Neanderthals living on until extinction.

5.  The Matter of Acculturation

The fate of the Neanderthals during the transition has to be considered in terms of speed of change, geographical extent, and type of change – cultural versus biological. There is a need to define incoming modern behaviour, social, cognitive, symbolic and ritual in comparison to that of Neanderthals. There are also contrasting hypotheses concerning the origins of AMH themselves. No hybridisation occurred but more evidence is required to resolve the issue of acculturation and displacement.

During the Middle Palaeolithic the Neanderthals used the Levallois technique – working flint and other stone to make flakes. The stone tool industry practised by Middle Palaeolithic Neanderthals was the Mousterian techno-complex (Lewis-Williams, 2002). The Upper Palaeolithic Cro-Magnon made thinner and longer blades from conical flint sources, as well as innovative bone tools – the Aurignacian techno complex.

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Examples of Aurignacian lithic technology.  Source: Course handout.

During the European Late Middle Palaeolithic pre-Aurignacian contexts, bone tools and ornamentation are interpreted as resulting from “…acculturation of final Neanderthal populations by anatomically modern humans.” (d’Errico, 1998). However, the acculturation of Arcy-sur-Cure Neanderthals is suggested by imitation AMH technology (Hublin, 1996). Due to different biology Neanderthals did not possess requisite intellectual capabilities to independently develop their own cultural and behavioural advances because of lack of speech skills (Chase, 1987). This model assumes imitation rather than acculturation (d’Errico, 1998), and is problematic because of the meaning of acculturation. Usually the term indicates an asymmetrical relationship between the  dominating and dominated with assimilation due to superiority – however, one definition is the “Transference of ideas, beliefs, traditions, and sometimes artefacts by long-term personal contact.” (Darvill, 2002). Acculturation is best considered in relation to the Chatelperronian Complex.

6.  Neanderthal Acculturation and the Chatelperronian Complex

The Neanderthal Chatelperronian of south-west France, some 38 to 33,000 years ago, employed Upper Palaeolithic technology and Middle Palaeolithic tool types. Remains were found at Arcy-sur-Cure (Grotte du Rennes). Similarity between Arcy-sur-Cure ornaments and those supposedly Aurignacian contexts  were assumed to be imitations or abandoned and gathered AMI artefacts (White, 1992), despite the Saint Cesaire record “…strongly suggesting that Neanderthals were solely responsible for the Chatelperronian assemblages.” (d’Errico, 1998).

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Examples of Chatelperronian and Gravettian lithic technology.  Source: Course handout.

1 to 5 Chatelperronian and 6 to 14 Gravettian.

The Chatelperronian Complex the first 5000 years of the Upper Palaeolithic, is associated with Neanderthals flourishing in Dordogne and parts of the Pyrenees (Harrold, 1989). This period shows contact between Aurignacian and Chatelperronians, at Roc de Combe and Piage, with Aurignacian  strata interspersed with Chatelperronian (Gamble, 1999), the two cultures co-existing and occupying the same rock shelters alternately. The Chatelperronian disappeared by 35,000 BP leaving the landscape to the Aurignacians. There are continuities between Mousterian and Chatelperronian tools (Mellars, 1996), the latter a terminal expression. Was the Chatelperronian an independent development (d’Errico, 1998) or the broader concensus that “…the distinctive features of the Chatelperronian developed as a result of contact with in-coming Aurignacian communities?” (d’Errico, 1998). Thus – spontaneous development, or selective imitation, or exchange with Aurignacians?” (Gamble, 1999).

Long tradition asserts Neanderthal intellectual inferiority but the presumption should be abandoned because “…the Chatelprronian represents a development of the preceding Mousterian or Acheulean Tradition.” (d’Errico, 1998), even though Neanderthals “…imitated certain aspects of modern behaviour…while they could emulate they could not understand.” (Stringer, 1993), with “…no strong archaeological evidence of substantial progress.” (Cavalli-Sforza, 1997).

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