Who Killed the Neanderthals?

Emiliano Carnieri

Published online: 11 January 2007# Springer Science + Business Media B.V. 2007

Abstract Homo neanderthalensis, evolved from the European populations of H.heidelbergensis, and shows some special morphological traits, probably due to anadaptation to particular climatic conditions. It also appears that H. neanderthals had aspecialized diet which was mostly carnivorous. Anatomically modern humans of theEuropean Upper Palaeolithic seem to differ from the alimentary behaviour thatcharacterized the Neanderthals; their diet was more varied, with a greater contributionfrom freshwater alimentary resources (molluscs and fishes). Comparison between thevarious strategies of subsistence adopted by the two species allows us to propose ahypothesis about the extinction of H. neanderthalensis.

Keywords H. neanderthals . diet . climatic adaptation . extinction

Introduction

Until a few decades ago, the evolution of human lineage was interpreted as an anagenetic, linearprocess: it was “simple” – a passage from biologically and culturally more archaic forms tomore progressive forms until the onset of our species. With new and improved researchtechniques (absolute dating and the study of DNA from living and fossil species) coupled withthe discovery of new fossils, there has been a profound change in the way we interpret theevolutionary history of hominids. In particular, it was shown that two or more species ofhominids coexisted in the same period and in the same territory. Apparently, multiple species ofhominids have been the rule, not the exception, for the past 2.5 million years.

Co-Existence of H. neanderthal and H. sapiens

The more famous and best-documented case of coexisting hominids regards the two speciesof the genus Homo, H. neanderthalensis and H. sapiens. There remains considerable

Human Evolution (2006) 21:337–340DOI 10.1007/s11598-006-9029-2

E. Carnieri (*)Museo di Storia Naturale del Mediterraneo, Via Roma 234, 57127 Livorno, Italye-mail: e.carnieri@provincia.livorno.it

discussion about the meaning and consequences of this “meeting”. The only certain data isthat modern humans replaced the Neanderthals, in the Levant and in the Europeancontinent, in several thousands of years, and that the genetic contribution of the latter tomodern human populations is null or insignificant [1]. More articulated and complex is thedebate about the lithic artefacts – i.e., the relationships between the Mousterian industries,the so-called industries of transition, and those of Upper Palaeolithic, and about theinteractions between the two species and the factors that determined the extinction of H.neanderthalensis. The Neanderthals evolved from European populations of H. heidelber-gensis, between 250,000 and 130,000 years B.P. This species is characterized by severalspecial morphological traits, probably due to an adaptation to particular climatic conditions.

Subsistence Strategies of H. neanderthal

Recently, d’Errico [4] emphasized that before and during the period of contact between thetwo species, there were no substantial behavioural and cultural differences (ecology andsubsistence strategies, lithic technology, ability to work bone and ivory materials, burials,use of colours and personal ornaments, etc). Only later, when H. neanderthalensis hadalready disappeared, H. sapiens developed a greater cultural diversification. In particular,the subsistence strategies of Neanderthals were based on hunting, including ungulates ofmedium and great dimensions. A recent study seems to demonstrate that the huntingpracticed by Neanderthals and by the first European anatomically modern humans showedthe same level of specialization. However, the diet of H. neanderthalensis was variablefrom a chronological and geographic point of view. Before 50,000 years B.P., the mostimportant food seemed to have been meat. In the following period, the diet was morediversified: Neanderthals also used other resources (molluscs, fishes, birds) as indicated byarchaeological evidence from Vanguard Cave, Devil Tower at Gibraltar and Moscerini Cave inItaly. The phenomenon seems interesting, especially when we consider sites in southernEurope, where Neanderthals survived longer. An analysis of the dental microwear of themandible teeth of the so-called “Gibraltar child” has shown amostly carnivorous diet, as seen inInuit and Fuegini populations [5]. Analysis of stable isotopes on Neanderthal specimens fromMarillac and Saint Césaire (France), Scladina (Belgium) and Vindija (Croatia) confirmedthese conclusions [6]. H. neanderthalensis seems to have been a species at the top of theecological pyramid, hunting animals of large and medium dimensions, even if – probably –vegetables were also included in the diet [3].

Draw Near Hunting, Paleopathology and Lithic Points

In addition, the study of Neanderthal palaeopathology suggests a strategy of hunting of“draw near” type: the Neanderthals probably confronted their victims from a short distance.A confirmation of the results of palaeopathological investigations comes from thecomparison of artefacts, such as projectile points attributed to H. neanderthal and thosemade by H. sapiens. Palaeolithic lithic points are different in terms of aerodynamics andaverage kinetic energy from those made of bone or stone dated to the Upper Palaeolithic.The former are more effective due to their low speed, but high penetration, for short-distance encounters, whereas the latter are more effective for killing an animal if launchedfrom a greater distance and with a greater speed [4, 7, 8].

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More Varied Diet in H. sapiens

Subsequently, since the Gravettian, the anatomically modern man seems to adopt a morevaried alimentary behaviour. The studies on dental microwear, stable isotopes and traceelements in archaeological bones, as well as archeological (enormous variability and wealthof the material culture) and zooarcheological evidence bear witness to a change towards adifferent subsistence (more varied diet and with a greater intake of alimentary resourcesfrom inner waters such as molluscs and fish) [3, 6]. Results from analyses of stable isotopeson the Upper Palaeolithic record from Russia, Czech Republic and England emphasize thisphenomenon. The study of trace elements on palaeolithic Italian remains (Paglicci andParabita, dated to the Gravettian; Continenza, Romanelli, Romito and Vado all’Arancio,dated to the Epipalaeolithic) [3] have indicated a considerable variability in the diet of thesehuman groups that covered a great part of the Upper Palaeolithic.

Hypothesis on H. neanderthal Extinction

Bearing these data in mind, it is possible to formulate a hypothesis that explains theextinction of H. neanderthalensis. Obviously, further studies and a greater amount of dataare necessary to confirm these suggestions. Extinction is part and parcel of biologicalevolution; it is a natural and unavoidable phenomenon. The passing away of a species ismore probable if some conditions take place: a limited area of distribution, populations ofsmall dimensions and therefore characterized by an important phenomenon of geneticdrifts, a long biological cycle, marked specialization, a high position within the trophicchain, and finally the arrival of a new species that occupies the same ecological niche. Inthis case, the extinction of a species is followed by the arrival of a new and morphologicallysimilar species: this is the case of H. neanderthalensis and H. sapiens.

Anatomically modern man reached Europe approximately 40,000 years ago andcohabited with the Neanderthals probably for few thousands years. It seems that the twoHomo species had similar strategies in hunting and gathering, similar diet and similarexploitation of the territory. It is difficult to establish if there was a direct competitionbetween the Neanderthals and anatomically modern humans and, in case there was, to whatextent. However, the arrival in Europe of H. sapiens and the extinction of Neanderthalsseem to be strongly connected. It is probable that various factors could have interactedtogether. The data which allowed the reconstruction of strategies of subsistence amongNeanderthals have indicated their role as super-predators in the ecosystem. The more or lessrapid climatic changes documented for that period could have determined the rarefaction orextinction of some preferential preys of Neanderthals and/or the shortage of territoriesavailable, with a consequent reduction of the population and “withdrawal” into climaticallyadequate shelter areas. In this situation, the Neanderthals could have adopted variousalimentary strategies (especially in the southern regions), a form of adaptation that hasenabled them to endure the various climatic crises of that period. It is possible that the arrivaland the presence of our species had impeded access to the usual or alternative alimentarysources that were previously only exploited by H. neanderthalensis. Moreover, a smalldifference in the mortality rate between the two species could have been a sufficient factorthat led to the extinction of Neanderthals. In the case of H. neanderthalensis and H. sapiens,the phenomenon could have been determined from various factors. One of the causes can befound in minimal differences in alimentary behaviour [2, 3] that favoured our species. The

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other cause could be attributed to the difference in hunting strategies. The strategy practicedby Neanderthals (short distance and/or drawn near) could have carried a higher risk, with agreater number of more or less serious injuries, compared to that practiced by anatomicallymodern men (at a greater distance). In conclusion, we can suppose that a compound ofclimatic, biological, behavioural and cultural factors had determined the decline, geneticisolation in small groups and, ultimately, extinction of Neanderthals.

References

1. Caramelli D, Lalueza-Fox C, Cristiano Vernesi C, Lari M, Casoli A, Mallegni F, Chiarelli B, Dupanloup I,Bertranpetit J, Barbujani G, Bertorelle G (2003) Evidence for a genetic discontinuity betweenNeanderthals and 24,000-year-old anatomically modern Europeans. PNAS 100:6593–6597

2. Carnieri E (2002) Microusura dentaria in popolazioni paleolitiche della Penisola Italiana, Tesi di Dottoratodi Ricerca in Archeoantropologia, XIV Ciclo (inedita), Università degli Studi di Torino, pp 1–149

3. Carnieri E, Tartarelli G, Bartoli F, Mallegni F (2002) Strategies of subsistence of European humanpopulations during the Middle and Upper Paleolithic. 13th Congress of the European AnthropologicalAssociation (Abstract), p 37

4. d’Errico F (2003) The invisible frontier. A multiple species model for the origin of behavioral modernity.Evol Anthropol 12:188–202

5. Lalueza-Fox C, Pérez-Pérez A (1993) The diet of the Neanderthal child Gibraltar 2 (Devil’s Tower)through the study of vestibular striation pattern. J Hum Evol 24:29–41

6. Richards M, Pettitt P, Stiner M, Trinkaus E (2001) Stable isotope evidence for increasing dietary breadthin the European mid-Upper Palaeolithic. PNAS 97:7663–7666

7. Shea J (1997) Middle Palaeolithic spear point technology. In: Knecht H (ed) Projectile technology.Plenum Press, New York, pp 79–106

8. Villa P, d’Errico F (2001) Bone and ivory points in the Lower and Middle Palaeolithic of Europe. J HumEvol 41:69–112

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