Tortoise taphonomy and tortoise butchery patterns at Blombos Cave, South Africa

Tortoises are one of the most common faunal components at many Palaeolithic archaeological sites across the Old World. They provide protein, fat, and other 'animal' resources in a 'collectable' package. However, for most sites their interpretation as human food debris is based only on association, rather than demonstrated through taphonomic analysis. Because of their very different anatomical configuration compared to mammals, it is difficult to conduct such analyses by directly applying the taphonomic methods used to interpret large mammal assemblages. Tortoise-specific taphonomic analysis is presented here for the Still Bay layers at the important Middle Stone Age (MSA) site of Blombos Cave (BBC), Western Cape, South Africa. Research on MSA subsistence systems at sites such as BBC has almost exclusively relied on analysis of large ungulate remains, in spite of the fact that many of these key sites contain equal or greater numbers of tortoise fragments. In this analysis we show that human modification is common on the BBC tortoises, and that there are consistent patterns of fragmentation and burning that indicate set processing sequences including cooking while in the shell, hammerstone percussion, and human chewing of limbs. The almost exclusive dominance of the angulate tortoise, Chersina angulata, is confirmed by full skeletal element analyses rather than only counts of single elements such as humeri. The sex distribution can be reconstructed for this species, and is female-biased. For all tortoise assemblages, taxonomic and skeletal element abundance data should be calculated from a sample of complete elements, or at minimum the entoplastron and humerus. A sample of shell and limb/girdle elements should also be subjected to microscopic bone surface modification analysis, as modifications are often rare or subtle but highly informative. Using this approach, analysis of breakage patterns, bone surface modification, and burning patterns can be understood together to specifically reconstruct tortoise collection, processing, and human dietary significance across a range of archaeological sites

Nutritional values of tortoises relative to ungulates from the Middle Stone Age levels at Blombos Cave, South Africa: Implications for foraging and social behaviour

The site of Blombos Cave (BBC), Western Cape, South Africa has been a strong contributor to establishing the antiquity of important aspects of modern human behaviour, such as early symbolism and technological complexity. However, many linkages between Middle Stone Age (MSA) behaviour and the subsistence record remain to be investigated. Understanding the contribution of small fauna such as tortoises to the human diet is necessary for identifying shifts in overall foraging strategies as well as the collecting and processing behaviour of individuals unable to participate in large-game hunting. This study uses published data to estimate the number of calories present in tortoises as well as ungulates of different body size classes common at South African sites. A single tortoise (Chersina angulata) provides approximately 3332 kJ (796 kcal) of calories in its edible tissues, which is between 20 and 30% of the daily energetic requirements for an active adult (estimated between 9360 kJ [3327 kcal] and 14,580 kJ [3485 kcal] per day). Because they are easy to process, this would have made tortoises a highly-ranked resource, but their slow growth and reproduction makes them susceptible to over-exploitation. Zooarchaeological abundance data show that during the ca. 75 ka (thousands of years) upper Still Bay M1 phase at BBC, tortoises contributed twice as many calories to the diet relative to ungulates than they did during the ca. 100 ka lower M3 phase. However, in spite of the abundance of their fossils, their absolute caloric contribution relative to ungulates remained modest in both phases. At the end of the site's MSA occupation history, human subsistence strategies shifted to emphasise high-return large hunted mammals, which likely precipitated changes in the social roles of hunters and gatherers during the Still Bay

Later Stone Age human hair from Vaalkrans Shelter, Cape Floristic Region of South Africa, reveals genetic affinity to Khoe groups

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Taphonomic analysis of the Middle Stone Age larger mammal faunal assemblage from Blombos Cave, southern Cape, South Africa

A detailed taphonomic analysis is reported for a sample of the larger mammalian faunal assemblage (>4.5\ua0kg live body weight) from Blombos Cave. The analysis provides an assessment of human involvement in the accumulation and modification of the faunal assemblage, and precedes equally detailed analyses and separate reports of Middle Stone Age (MSA) butchery, transport, and hunting behaviour. At Blombos, there are clear differences in the relative abundances of ungulate body size classes, with the lower MSA phases (upper/lower M2 and M3) showing a high representation of size 1 ungulates relative to the most recent MSA phase (M1). The bones from the earliest MSA phase (M3) have not undergone much post-depositional fragmentation, in contrast to fragments from more recent phases (M1 and upper M2). Much of this variability can be attributed to more burning activity and trampling during M1 and upper M2, which could indicate more intensive occupation. Bone surfaces are variably preserved, with high levels of exfoliation in the most recent two phases. Surface modification analyses revealed high proportions of human modification throughout the sequence, indicating that MSA humans were responsible for accumulating most of the larger mammals. After discard, the bones were modified by scavenging carnivores, leading to a moderate amount of density-mediated destruction and tooth-marking. Carnivores independently accumulated some of the smaller ungulates, mainly in the form of partially-digested remains. Raptorial birds are not implicated as major faunal accumulators. The results from Blombos are directly comparable with analogous datasets from two other sites in the Western Cape (Pinnacle Point Cave 13B and Die Kelders Cave 1). Such comparisons demonstrate that MSA faunal assemblages from nearby coastal sites have complex and different taphonomic histories both within and between sites. Because the human occupants were a major part of these processes, MSA subsistence behaviour and site use was also quite variable over time and space

Early Use of Pressure Flaking on Lithic Artifacts at Blombos Cave, South Africa

Pressure flaking has been considered to be an Upper Paleolithic innovation dating to ~20,000 years ago (20 ka). Replication experiments show that pressure flaking best explains the morphology of lithic artifacts recovered from the ~75-ka Middle Stone Age levels at Blombos Cave, South Africa. The technique was used during the final shaping of Still Bay bifacial points made on heat‐treated silcrete. Application of this innovative technique allowed for a high degree of control during the detachment of individual flakes, resulting in thinner, narrower, and sharper tips on bifacial points. This technology may have been first invented and used sporadically in Africa before its later widespread adoption

Engraved ochres from the Middle Stone Age levels at Blombos Cave, South Africa

Powerful categories of evidence for symbolically mediated behaviour, variously described as ‘modern’ or ‘cognitively modern’ human behaviour, are geometric or iconographic representations. After 40,000 years ago such evidence is well documented in much of the Old World and is widely considered as typifying ‘modern human culture,’ but earlier evidence is rare. In Africa, this includes two deliberately engraved ochre pieces from c. 75,000 year old levels at Blombos Cave, Western Cape, South Africa and the greater than 55,000 year old incised ostrich egg shell from the Diepkloof shelter, located in the same province. Here we report on thirteen additional pieces of incised ochre recovered from c. 75,000–100,000 year old levels at Blombos Cave. These finds, taken together with other engraved objects reported from other southern African sites, suggest that symbolic intent and tradition were present in this region at an earlier date than previously thought

Shellfish exploitation during the Oakhurst at Klipdrift Cave, southern Cape, South Africa

Klipdrift Cave in the southern Cape, South Africa, provides new insights into shellfish harvesting during the Later Stone Age (14–9 ka) period associated with the Oakhurst techno-complex. Two shellfish species dominate: Turbo sarmaticus and Dinoplax gigas. An abrupt shift in the relative frequencies of these species occurs in the middle of the sequence with T. sarmaticus almost completely replacing D. gigas. The shift in dominant species is likely due to environmental change caused by fluctuating sea levels rather than change in sea surface temperatures. The shellfish assemblage shows that local coastal habitats at Klipdrift Cave were somewhat different from those of contemporaneous sites in the southern Cape. Although the shellfish specimens are smaller at Klipdrift Cave than those from Middle Stone Age localities such as Blombos Cave, there is no robust indication that larger human populations at Klipdrift Cave during the Oakhurst period might have caused this change in size. Environmental or ecological factors could have restricted shellfish growth rates as some experimental works have suggested, but this possibility also remains to be further explored. Significance: The dominance of D. gigas and T. sarmaticus at Klipdrift Cave is surprising, as it indicates a local habitat slightly different from other similar sites during the Oakhurst period. The shift in dominance from D. gigas to T. sarmaticus indicates changing climatic and environmental conditions during the Oakhurst period, 14–7 ka

Assessing the accidental versus deliberate colour modification of shell bead: a case study on perforated Nassarius kraussianus from Blombos Cave Middle Stone Age levels

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Hidden in plain sight: A microanalytical study of a Middle Stone Age ochre piece trapped inside a micromorphological block sample

A complete Middle Stone Age ochre piece was unintentionally collected and fully preserved within a micromorphological block sample intended to characterise a 74 ± 3 ka occupation horizon at Blombos Cave, South Africa. Previously recovered ochre pieces from the same stratigraphic context (Still Bay) have displayed intricate modification patterns with significant behavioural implications. Yet, in the case of the trapped ochre, a direct visual assessment of its surfaces was impossible due to its impregnated state. In this study, we demonstrate how we successfully reconstructed three‐dimensionally and characterised the block‐sampled ochre piece using high‐resolution microcomputed tomography scanning coupled with a range of microanalytical techniques, including optical petrography, micro‐Fourier transform infra‐red spectroscopy, micro‐X‐ray fluorescence and micro‐Raman spectroscopy. Through a morphometric analysis of the score marks present on the trapped ochre's reconstructed surface, we were able to assess the types of modifications and the nature of the actions that created them. Our results show that a block sample‐based study of archaeological artefacts allows for a comprehensive assessment of their depositional and microcontextual setting, their external morphology and microtopography, as well as their internal texture and geochemical properties. We suggest that this type of context‐sensitive, multiscalar and multidisciplinary investigation may also prove beneficial in the study of conventionally recovered archaeological artefacts.Fundação Amazônia Paraense de Amparo à Pesquisa http://dx.doi.org/10.13039/501100005288Norges Forskningsråd http://dx.doi.org/10.13039/501100005416Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659FP7 Ideas: European Research Council http://dx.doi.org/10.13039/10001119