Paleolithic Neanderthal Research: Biological, Social and Environmental Issues

The sudden extinction of Neanderthals has been the subject of studies for more than two centuries. Even though the causes have not been determined, various hypotheses have been put forward in the endeavor to interpret what triggered their extinction. The basic model that prevails today as the elucidation of Neanderthal man's extinction, is that of genetic assimilation by Homo sapiens and the Denisovans, something that was analyzed in the previous chapter. There are, however, other theories relying on data which illustrates what may have contributed to the gradual decline and eventual extinction of the species.

Figure 1: Reconstruction of a Neanderthal man based on fossils.

A population's use of technology and way of action are related to its geographical location and the prevailing climate. Neanderthals in Northern and Western Europe survived in the steppes of a slightly warmer climate up to 60,000 years ago. However, with the change of climat during the last glacial period, they began to move to the Iberian Peninsula, where a milder environment still prevailed. This created the need for technological adaptation. Gradually, the cold climate began to affect the Mediterranean area. Modern man had managed to fully adapt to the natural environments created by the cold climate, in contrast to the Neanderthals who did not manage to find technologies that would lead to their survival. (Banks et al., 2008)

According to one scientific view Iberia was a refuge for the last Neanderthals (Jiménez-Espejo et al., 2007). They survived up to 30-28 ka BP, but no later when climatic conditions changed and became very inhospitable to an already limited population. In order to understand the local climate change, paleoclimatic studies have been carried out through palynological and sedimentological records. Although studies alone cannot confirm the contribution of climate to the Neanderthal extinction process, what local archives conclude is that there were significant fluctuations and changes in the western Mediterranean area during the period under discussion (45-24 ka BP). Comparisons with other records show that conditions worsened between 24 and 25 ka BP. At the same time Moreover, this period is identified with the gradual appearance and predominance of modern people. In general, climate-environmental theories are many manyfold and can differ radically depending on who is carrying out the research.

Figure 2: An exhibit shows the life of a Neanderthal family in a museum in northern Croatia.

The first hypothesis regarding climate involvement in the Neanderthal's extinction was that of Leroyer and Leroi-Gourhan (1983). The authors proposed a scenario according to which the populations of modern people who used the Aurignacian stone carving, coming from the East, colonized southern France and northern Iberia. This happened between 34 and 32.5 ka BP. During this period, the Neanderthals of the Châtelperronian industry were still active in the above areas. According to Leroyer and Leroi-Gourhan's (1983) theory, during the next cold period, the two groups coexisted during the next cold period. At the end of this period and before the warm phase which can be situated around 32.5–30 ka BP, the Châtelperronian sites, and therefore the Neanderthals, gradually appear to be circumscribed to the northeast.

Finlayson (2009) suggested that the issue of Neanderthal extinction can be seen from a purely ecological point of view. In their opinion, the main reason for the extinction of Neanderthals was the cessation of their seasonal activity, a change that is responsible for the climatic situation at the end of OIS 3 (oxygen isotope stages - alternating warm and cool periods in the Earth's paleoclimate). The research was based on the study of Gorham Cave, in which in addition to archaeological finds, remnants of old fauna and flora have also been found, recording the change in OIS 3. The main conclusion is that for most of OIS 3, Neanderthals of the southern Iberian Peninsula lived in a Mediterranean savannah, which had as a consequence of regulating their lives at a rate that may seem extremely seasonal but nevertheless stable throughout the year. The consequence of the colder climatic conditions brought about by the end of OIS 3 was the dramatic change of the Iberian environment, into a dense pine forest on the coasts and a steppe inland vegetation.

Figure 3: Modern man during last glacial period.

These changes would also bring about changes in the biomass of the area, changes which would be offset a little by the arrival of higher-altitude marine mammals or migratory birds. However, the main result of all this would be the cessation of the steady cycle of seasonal activities of the Neanderthal teams in a short period of time, which would greatly weaken their population, especially if combined with the advent of modern man.

Homo neanderthalensis rivalry with Homo sapiens and the lifestyles of the two species played a role in the issue. Neanderthal culture did not have as in-depth symbolic and progressive thinking as modern humans, and this may have made competition difficult (Finlayson C., 2009). Neanderthal culture remained relatively static, while Homo sapiens evolved steadily with complex behaviors. By the time Homo sapiens arrived in Europe 40,000 years ago, it had a highly developed cultural system. This is despite the fact that 100,000 years ago there was virtually no cultural difference between the two species based on archaeological data. Modern man had begun to produce his own food from nature, he was more social and therefore in larger groups, the stone carvings were more efficient than the mysteries and Levallois technique developed by the Neanderthals. Even the Sapiens' most complex clothing in cold climates played a role in relation to the Neanderthals who did not adapt in the same way.

Figure 4: A resting Neanderthal woman.

Even more interesting is the view of Pat Sipman, who in her 2015 book entitled The invaders: how humans and their dogs drove Neanderthals to extinction, argues that an important role in the development of modern human society to the detriment of Neanderthals played the use of wolves-dogs to help hunt large prey. This conclusion was reached after studying findings in Siberia and Belgium dating back 33,000 years BP and including wolf bones that have the characteristics of domestic animals.

Neanderthals may have lacked the adaptive nature of modern humans who could settle en masse in large areas. The smaller Neanderthal populations that used to live in remote and low-potential areas may have made them vulnerable to local extinctions. In addition, Neanderthals may not have used their brains as modern humans do, as their brains were shaped differently (Takanori K. et al, 2018) - in modern humans the brains have extensive parietal and cerebellar areas. These areas develop during the first year of life and are associated with key functions such as the ability to integrate sensory information and form abstract representations of the environment. Neanderthals appear to have missed this stage of development.

Figure 5: A model of a Neanderthal child at the Neanderthal Museum in Krapina, Croatia.

Last but not least, violent interactions with modern humans were possible. The two species may not only have had intercourse with each other but in some cases, there was violence. Competition in different areas and limited looting may have led to controversy (Conard N. et al, 2006). This theory is based on several findings of both species presenting injuries, which could only have been caused by spikes. However, this model of competition is no longer considered so widespread in relation to the usual relations between Neanderthals and modern humans. Although there have been incidents of violence, they do not appear to have played a significant role in the extinction of Homo neaderthalensis.

Bibliographical References

Banks, W., d'Errico, F., Peterson, A., Kageyama, M., Sima, A., & Sánchez-Goñi, M. (2008). Neanderthal Extinction by Competitive Exclusion. Plos ONE, 3(12), e3972. https://doi.org/10.1371/journal.pone.0003972

Finlayson, C. (2009). Neanderthals and modern humans. Cambridge University Press.

Jiménez-Espejo, F., Martínez-Ruiz, F., Finlayson, C., Paytan, A., Sakamoto, T., & Ortega-Huertas, M. et al. (2007). Climate forcing and Neanderthal extinction in Southern Iberia: insights from a multiproxy marine record. Quaternary Science Reviews, 26(7-8), 836-852. https://doi.org/10.1016/j.quascirev.2006.12.013

Kochiyama, T., Ogihara, N., Tanabe, H., Kondo, O., Amano, H., & Hasegawa, K. et al. (2018). Reconstructing the Neanderthal brain using computational anatomy. Scientific Reports, 8(1). https://doi.org/10.1038/s41598-018-24331-0

Leroyer, C., & Leroi-Gourhan, A. (1983). Problèmes de chronologie: le castelperronien et l'aurignacien. Bulletin De La Société Préhistorique Française., 80(2), 41-44.

Shipman, P. (2015). The invaders : how humans and their dogs drove Neanderthals to extinction.. Belknap Press.

Visual Sources

Figure 1: Anonymous. (2016). Reconstruction of a Neanderthal man based on fossils. [Live Reconstruction]. Retrieved from: https://www.neanderthal.de/de/urmenschen.html

Figure 2: Solic N. (2010). An exhibit shows the life of a Neanderthal family in a museum in northern Croatia. [Photo]. Retrieved from: https://theworld.org/stories/2016-02-17/humans-started-having-sex-neanderthals-way-earlier-thought

Figure 3: De Armas E. (n.d.). Modern man during last glacial period. [Visual Painting]. Retrieved from: https://ec.europa.eu/research-and-innovation/en/horizon-magazine/ice-age-europeans-roamed-small-bands-fewer-30-brink-extinction

Figure 4: Björklund T. (2018). A resting Neanderthal woman. [Visual painting]. Retrieved from: https://aeon.co/essays/what-do-we-know-about-the-lives-of-neanderthal-women

Figure 5: Solic N. (2010). A model of a Neanderthal child at the Neanderthal Museum in Krapina, Croatia. [Photo]. Retrieved from: https://aeon.co/essays/you-might-be-closer-to-the-neanderthals-than-you-thought