Neanderthals versus Modern Humans: Evidence for Resource Competition from Isotopic Modelling

doi:10.4061/2011/689315

Virginie Fabre, Silvana Condemi, Anna Degioanni and Estelle Herrscher

During later MOIS3, in Europe two populations were present, autochthonous Neanderthals and modern humans. Ecological competition between these two populations has often been evoked but never demonstrated. Our aim is to establish whether resource competition occurred. In this paper, in order to examine the possibility of ecological competition between these two populations, 599 isotopic data were subjected to rigorous statistical treatment and analysis through mixing models. The aim of this paper was to compare dietary strategies of Neanderthals and modern humans over time. Our conclusions suggest that Neanderthals and modern humans shared dietary habits in the particular environmental context of MOIS3 characterised in Europe by climatic deterioration. In this environmental context, the resource competition between Neanderthals and modern humans may have accelerated the disappearance of the Neanderthal population.

Climate and the demise of the Neandertals

From "Time for the Middle to Upper Paleolithic transition in Europe"

by Wil Roebroeks; Faculty of Archaeology, Leiden University, P.O. Box 9515, 2300RA Leiden, The Netherlands

http://dx.doi.org.ezproxy.lib.utexas.edu/10.1016/j.jhevol.2008.08.008

Ice core studies have taught us that the time span of Middle and Upper Paleolithic was punctuated by rapid climatic transitions on timescales of centuries or even decades (Adams et al., 1999). Vegetation responses to such rapid fluctuations must have varied on small scales among sites and regions, according to the differences in initial environmental conditions, local and regional species pool, and the climate events concerned, and the same applies to faunal elements, including Neandertals and modern humans. Various authors have suggested that such climatic fluctuations were instrumental in the disappearance of the Neandertals, one of the latest climatic hypotheses having been presented by Mellars (2006) who suggests that their final demise may have coincided with the sudden onset of the much colder and drier conditions of the Heinrich Event 4. However, extremes of temperatures reached during this period were not exceptional, and had been experienced in earlier glacial-interglacial cycles survived by Neandertals, where the extremes of OIS 4 and 6 led to abandonment of the northern parts of Europe, as did the most extreme parts of OIS 2, for modern humans (e.g., Roebroeks et al., 1992). Recently Tzedakis et al. (2007) have also made the point that climate change was probably not the key factor here, as before 28 ka ¹⁴C BP (i.e., according to most of the papers in this volume long after their demise) Neandertals would have faced a pattern of climatic fluctuations that they had been surviving for at least 100,000 years already.

The consequences of Middle Paleolithic diets on pregnant Neanderthal women

http://dx.doi.org.ezproxy.lib.utexas.edu/10.1016/j.quaint.2011.07.002

The authors critique various assumptions made by others about Neanderthal lifeways by showing that Neanderthal births would be impossible under these conditions.

3. Lessons learned
There are a large number of potential lessons to be learned here. Principle among them is that researchers should consider the possibility that previous models have, to one degree or another:

1. Under-appreciated the Neanderthals’ abilities to regulate body temperature;
2. Under-appreciated the Neanderthals’ abilities to efficiently hunt terrestrial animals;
3. Under-appreciated the degree of sexual division of labor within Neanderthal groups generally, and for pregnant and lactating women, specifically;
4. Under-appreciated the amount of non-mammal foods eaten by Neanderthals, such as fish, shellfish, insects, birds and eggs;
5. Under-appreciated the amount of plant foods eaten by Neanderthals;
6. Under-appreciated the differences in metabolic processing of essential nutrients such as protein between Neanderthals and modern humans;
7. Under-appreciated the role of micronutrient deficiencies to Neanderthal extinction;
8. Exaggerated the degree of mobility in the average Neanderthal group compared to modern hunting-gathering societies; and
9. Exaggerated the degree of close-encounter, dangerous hunting techniques that Neanderthal women participated in.

Transitions or turnovers?

http://dx.doi.org.ezproxy.lib.utexas.edu/10.1016/j.quascirev.2008.08.015

John J. Shea (2008)

Abstract

The East Mediterranean Levant is a focal point for debate about evolutionary continuity among Late Pleistocene hominin populations. Changes in the Levantine Middle and Upper Palaeolithic archaeological records are almost invariably described in terms of adaptive shifts and behavioural transitions, rather than as changes in hominin populations. This paper examines evidence for hominin evolutionary continuity in the Levant between 130 and 25 ka. Two inflection points, one within the Middle Palaeolithic ca 75 ka and the other between the Middle and Upper Palaeolithic ca 45 ka, are examined in light of recently-discovered evidence for rapid climate change and environmental deterioration. It is proposed that both periods mark regional extinctions and turnovers of hominin populations. The first of these occurred among early Homo sapiens, the second among Neanderthals. Each event was followed by dispersal of hominin populations into the Levant from adjacent regions. Differences in Middle vs. Upper Palaeolithic Homo sapiens’ long-term success in the Levant may reflect recently-evolved strategies for coping with rapid climate change and with colder arid habitats.

Longevity. Cultural or Biological?

Is Human Longevity a Consequence of Cultural Change or Modern Biology?

By Caspari and Lee

DOI 10.1002/ajpa.20360

So they look at the OY ratio of human and neanderthals from Europe and western Asia at different time periods. Here's the sample:

They then cast some stats voodoo:

The approach of data-resampling provides a way to solve problems that lie outside the analytical boundaries of classical statistics (Efron and Tibshirani, 1993), e.g., using ratios as the statistic of interest, as in this study. Resampling also addresses the problem of interdependence of data within the death distribution, and the potential further dependence of later samples on earlier ones because of evolutionary change. As in our previous study, the null hypothesis that there is no difference in OY ratios among the different hominid groups can be stated as a question of probability: how likely is it to observe an OY ratio of a particular hominid group in another group of interest? When the test group’s OY ratio was smaller than that of the resampled group, we rejected the null hypothesis if a ratio the same as or lower than the observed OY ratio was found, on average, in 5% or less of the distribution generated from the comparative group. When the test group’s OY ratio was larger than that of the resampled group, we rejected the null hypothesis if, on average, 5% or less of the distribution was the same as or greater than the observed OY ratio.

So the OY ratio is different amongst Asian early moderns and Upper Paleolithic moderns and is different amongst Neanderthals from Europe and Asia. It is NOT different between Asian moderns and Neanderthals.

In sum, space and time make a difference, not phylogeny.

Neanderthal Thermoregulation and the Glacial Climate

Aiello - Wheeler 2003 Climate and Cold Adaptation.pdf

Main questions:

1. In terms of both energetic cost and survival, what quantitative advantage did the Neanderthal cold adapted body form provide at low environmental temperatures?
   
2. What were the actual environmental conditions that prevailed in Europe and European Russia at the time of Neanderthal occupation?

Kleiber equation (1961):

BMR(W) = 3.4 × mass(kg)^0.75

The values predicted by this equation show good agreement with those of living humans and other primates (Aiello & Wheeler 1995).

Based on the inferred body mass and stature data presented in Table 9.1 and the assumptions outlined above, the three hominin body forms show very little difference in the ambient temperature at which thermoregulatory thermogenesis must be initiated or in the minimum sustainable ambient temperature at which a heat production equivalent to 3 times BMR is reached (Table 9.2; Fig. 9.1). Neanderthals with a BMR predicted by the Kleiber equation would need to initiate additional heat production at 27.3°C (81.2°F) 1 , Homo erectus at 28.5°C (83.3°F) and Homo sapiens at 28.2°C (82.7°F). The minimum sustainable ambient temperature for Neanderthals would be 8.0°C (46.5°F), for Homo erectus 11.6°C (52.8°F) and for Homo sapiens 10.5°C (50.9°F).

An X-Linked Haplotype of Neandertal Origin Is Present Among All Non-African Populations

labuda - Neandertal haplotype in humans.pdf

An X-Linked Haplotype of Neandertal Origin Is Present Among All Non-African Populations (2012)

doi:10.1093/molbev/msr024

Recent work on the Neandertal genome has raised the possibility of admixture between Neandertals and the expanding population of Homo sapiens who left Africa between 80 and 50 Kya to colonize the rest of the world. Here, we provide evidence of a notable presence (9% overall) of a Neandertal-derived X chromosome segment among all contemporary human populations outside Africa. Our analysis of 6,092 X-chromosomes from all inhabited continents supports earlier contentions that a mosaic of lineages of different time depths and different geographic provenance could have contributed to the genetic constitution of modern humans. It indicates a very early admixture between expanding African migrants and Neandertals prior to or very early on the route of the out-of-Africa expansion that led to the successful colonization of the planet.

http://news.discovery.com/human/genetics-neanderthal-110718.html