Wil Roebroeks’s research while affiliated with Leiden University and other places

We review palaeoenvironmental proxies and combinations of these relevant for understanding hunter-gatherer niche construction activities in pre-agricultural Europe. Our approach consists of two steps: (1) identify the possible range of hunter-gatherer impacts on landscapes based on ethnographic studies; (2) evaluate proxies possibly reflecting these impacts for both the Eemian (Last Interglacial, Middle Palaeolithic) and the Early–Middle Holocene (Mesolithic). We found these paleoenvironmental proxies were not able to unequivocally establish clear-cut differences between specific anthropogenic, climatic and megafaunal impacts for either time period in this area. We discuss case studies for both periods and show that published evidence for Mesolithic manipulation of landscapes is based on the interpretation of comparable data as available for the Last Interglacial. If one applies the ‘Mesolithic’ interpretation schemes to the Neanderthal record, three common niche construction activities can be hypothesised: vegetation burning, plant manipulation and impact on animal species presence and abundance. Our review suggests that as strong a case can be made for a Neanderthal impact on landscapes as for anthropogenic landscape changes during the Mesolithic, even though the Neanderthal evidence comes from only one high-resolution site complex. Further research should include attempts (e.g. by means of modelling studies) to establish whether hunter-gatherer impact on landscapes played out at a local level only versus at a larger scale during both time periods, while we also need to obtain comparative data on the population sizes of Last Interglacial and Holocene hunter-gatherers, as these are usually inferred to have differed significantly.

Control of fire is one of the most important technological innovations within the evolution of humankind. The archaeological signal of fire use becomes very visible from around 400,000 y ago onward. Interestingly, this occurs at a geologically similar time over major parts of the Old World, in Africa, as well as in western Eurasia, and in different subpopulations of the wider hominin metapopulation. We interpret this spatiotemporal pattern as the result of cultural diffusion, and as representing the earliest clear-cut case of widespread cultural change resulting from diffusion in human evolution. This fire-use pattern is followed slightly later by a similar spatiotemporal distribution of Levallois technology, at the beginning of the African Middle Stone Age and the western Eurasian Middle Paleolithic. These archaeological data, as well as studies of ancient genomes, lead us to hypothesize that at the latest by 400,000 y ago, hominin subpopulations encountered one another often enough and were sufficiently tolerant toward one another to transmit ideas and techniques over large regions within relatively short time periods. Furthermore, it is likely that the large-scale social networks necessary to transmit complicated skills were also in place. Most importantly, this suggests a form of cultural behavior significantly more similar to that of extant Homo sapiens than to our great ape relatives.

In studies of hominin adaptations to fire use, the role of the aryl hydrocarbon receptor (AHR) in the evolution of detoxification has been highlighted, including statements that the modern human AHR confers a significantly better capacity to deal with toxic smoke components than the Neanderthal AHR. To evaluate this, we compared the AHR-controlled induction of cytochrome P4501A1 (CYP1A1) mRNA in HeLa human cervix epithelial adenocarcinoma cells transfected with an Altai-Neanderthal or a modern human reference AHR expression construct, and exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). We compared the complete AHR mRNA sequences including the untranslated regions (UTRs), maintaining the original codon usage. We observe no significant difference in CYP1A1 induction by TCDD between Neanderthal and modern human AHR, whereas a 150–1,000 times difference was previously reported in a study of the AHR coding region optimized for mammalian codon usage and expressed in rat cells. Our study exemplifies that expression in a homologous cellular background is of major importance to determine (ancient) protein activity. The Neanderthal and modern human dose–response curves almost coincide, except for a slightly higher extrapolated maximum for the Neanderthal AHR, possibly caused by a 5′-UTR G-variant known from modern humans (rs7796976). Our results are strongly at odds with a major role of the modern human AHR in the evolution of hominin detoxification of smoke components and consistent with our previous study based on 18 relevant genes in addition to AHR, which concluded that efficient detoxification alleles are more dominant in ancient hominins, chimpanzees, and gorillas than in modern humans.

Mollusc biogenic carbonates are valuable records of past environmental conditions. In particular, carbonate oxygen (δ¹⁸O) and carbon (δ¹³C) stable isotopes can be used to reconstruct different physical and chemical parameters, according to the different genera used (marine, freshwater or terrestrial). The Last Interglacial (early Eemian) palaeolake of Neumark‐Nord 2 (NN 2), Germany provides an excellent example of a Neanderthal archaeological site with abundant freshwater carbonate remains. As in other European contexts, one of the most abundant species is Bithynia tentaculata . In order to provide a robust regional baseline for the interpretation of the archaeological data, this study includes a calibration phase on modern B. tentaculata opercula. The results indicate that these calcitic structures are likely to be subjected to a growth slowdown/cessation during summer, which influences their geochemistry, reflecting mainly the water properties of the rest of the year. This modern calibration, together with the existing palaeoenvironmental reconstructions developed for NN 2 (e.g. pollen data), represents a valuable opportunity to establish B. tentaculata opercula as reliable environmental proxies applicable to several other freshwater contexts. The isotope data of the NN 2 opercula, in agreement with the pollen record, indicate that the major archaeological horizon was formed during a rather wet period and potentially in a semi‐forested environment. However, human occupation occurred also during drier phases at the site and within a wide temperature range, indicating the absence of restricted environmental preferences by the local Neanderthal groups.

The high-resolution palaeoenvironmental record from the last interglacial (Eemian) lakeland at NeumarkNord (Saxony-Anhalt, Germany) holds the rare potential to study Neanderthal subsistence ca.125,000 years ago in remarkable detail. Using the palynological record from the large lake Neumark-Nord 1 (NN1) and the adjacent small “pool” Neumark-Nord 2 (NN2) a sequence of lithic and faunal assemblages has been established, indicating Neanderthal presence in the lakeland throughout the Eemian. Calculations of the herbivore carrying capacity for the Neumark area during the Eemian reveal high biomass estimates. Using these estimates it was possible to calculate the structure of the source population, based on the faunal record rich in species and individuals, from littoral deposits assigned to the frst mesocratic phase of the Eemian. The results can be used as a frame of reference for making inferences on subsistence opportunities and prey selection based on taphonomical and zooarchaeological studies of the Neumark-Nord faunal assemblages. In a broader perspective our study demonstrates the benefts from inferring energy values (kcal) and body mass (kg) as ancillary parameters to zooarchaeological analyses to understand the relationships between death assemblage and their habitats from which they originate.

The high-resolution palaeoenvironmental record from the last interglacial (Eemian) lakeland at Neumark-Nord (Saxony-Anhalt, Germany) holds the rare potential to study Neanderthal subsistence ca. 125,000 years ago in remarkable detail. Using the palynological record from the large lake Neumark-Nord 1 (NN1) and the adjacent small "pool" Neumark-Nord 2 (NN2) a sequence of lithic and faunal assemblages has been established , indicating Neanderthal presence in the lakeland throughout the Eemian. Calculations of the herbi-vore carrying capacity for the Neumark area during the Eemian reveal high biomass estimates. Using these estimates it was possible to calculate the structure of the source population, based on the faunal record rich in species and individuals, from littoral deposits assigned to the first mesocratic phase of the Eemian. The results can be used as a frame of reference for making inferences on subsistence opportunities and prey selection based on taphonomical and zooarchaeological studies of the Neumark-Nord faunal assemblages. In a broader perspective our study demonstrates the benefits from inferring energy values (kcal) and body mass (kg) as ancillary parameters to zooarchaeological analyses to understand the relationships between death assemblage and their habitats from which they originate.

Here we present phosphate oxygen isotope (d 18 O PO4) data from horse (Equus sp.) tooth enamel (bio-apatite) from the early Eemian and early Weichselian find levels at the archaeological site of Neumark-Nord 2, Germany. Based on the relationship between d 18 O PO4 of bioapatite, body water, local precipitation and air temperature, these data are used to reconstruct palaeoclimatic conditions contemporary to the different phases of Neanderthal activity at the site. Bulk enamel samples representing one year of growth were taken from horse teeth from early Eemian (NN2/2b [~121 ± 5 ka], and NN2/1c) and early Weich-selian (NN2/0;~93 ± 7 ka) find levels, and d 18 O PO4 values were then utilised to calculate d 18 O of local environmental water and mean annual air temperature (MATs) during these phases of MIS5. Results indicate that during the early Eemian MAT was~9 C, with some evidence of variability through time. Although~3 C lower, the calculated early Weichselian MAT exceeds that indicated by other local and regional climate proxy datasets, suggesting that Neanderthal activity may have coincided with more ameliorate phases of the early Weichselian in this area.