Testing the “shift in the balance of power” hypothesis at Swartkrans, South Africa: Hominid cave use and subsistence behavior in the Early Pleistocene

C.K. Brain documented two interesting patterns in the Pleistocene faunas of Swartkrans Cave, South Africa: (1) The earliest depositional units, Members 1 and 2, preserve high numbers of hominid fossils, while the numbers drop sharply in the more recent Member 3. (2) Burned bone specimens, which seem to have been altered in fires tended by hominids, appear for the first time in Member 3. It was suggested that mastery of fire provided a “shift in the balance of power”, allowing hominids to carry out activities in the cave for the first time unmolested by predators. A lack of butchered bones in Members 1 and 2 and their presence in Member 3 provided support for the hypothesis. However, we have now identified butchered bones in all three units. Further, our findings reveal a lack of variability in butchery patterns through time at Swartkrans; in all cases hominids appear to have been proficient carcass foragers. The real “shift” at Swartkrans does not appear to be one of eventual hominid dominance over carnivores, but rather one of a predominance of leopards at Swartkrans in Member 1 times to the alternating presence of leopards and hyenas in Members 2 and 3. Consistent leopard presence in Member 1 seems to have discouraged hominid activity in the vicinity of the cave. In contrast, by the time Members 2 and 3 were forming hominids may have temporarily used the cave, taking advantage of those periods of carnivore absence.     

Carcass damage and digested bone from mountain lions (Felis concolor): implications for carcass persistence on landscapes as a function of prey age

This actualistic study examines the taphonomic signatures of modern free-ranging mountain lions (Felis concolor) on prey skeletal remains left at kill sites and digested bone fragments in the lions’ scats. Conducted in western Texas and southeastern New Mexico (U.S.A.), the study and its outcomes are relevant to models of carcass persistence and scavenging opportunities on ancient landscapes. Mountain lions in the study area ingested disproportionate quantities of bone from very young prey. This tendency holds true irrespective of prey body size. The results meanwhile confirm a relatively mild pattern of damage to adult deer carcasses. Digestive erosion of the surfaces of bones that passed through the gut was relatively severe, but many of these bone and tooth specimens retained identifiable features. It is clear that the mountain lions quickly remove the carcasses of very young prey from the pool of potentially scavenge-able resources. The non-linear relation between bone destruction from feeding by the cats and the skeletal maturity of prey also has consequences for prey mortality patterns, specifically a bias against the representation of very young individuals. This effect is not sufficient, however, to produce a global bias to prime-adult prey because older juveniles are much less affected.     

The trouble with transformations: Effects of sample size and sample composition on meat weight estimates based on skeletal mass allometry

The application of skeletal allometry in zooarchaeological analysis has increased in recent years. Two approaches can be distinguished, one based on linear measurements of bones for the purpose of estimating animal size and the other using skeletal weight to estimate dietary contribution. Here the application of the latter is examined. It is suggested that this method, as presently used with fragmentary remains, may not provide a dependable characterization of the relative contributions of identified taxa.     

Tracking changes in bone fracture morphology over time: environment, taphonomy, and the archaeological record

Zooarchaeologists have often employed studies of bone fracture morphology as a means of understanding past human cultural activity, and various methodological approaches have been developed for analyzing archaeological broken bone assemblages. It is widely understood that bones degrade over time, however, few studies have attempted to define and quantify the rate at which bones degrade and fracture morphologies change. This study examines degradation in frozen bones (−20 °C) and bones exposed to hot (40 °C) dry conditions. These two simulated environmental conditions represent extreme real-world climates, and allow for an actualistic understanding of the rates of degradation that bones experience in nature. When frozen, bones degrade slowly but significantly, and demonstrate measurable differences in samples frozen for 1, 10, 20, 40, and 60 weeks. In hot, dry conditions, bones degrade very quickly, and demonstrate measurable differences after 1, 3, 7, 14, and 21 days. These data allow for a more detailed understanding of the relationship between the cultural and natural processes that result in bone fracture, and the time period during which bones can be expected to maintain fresh fracture characteristics. This research also has implications for understanding human subsistence and survival strategies and for interpreting the archaeological record.     

Skeletal element abundances in archaeofaunal assemblages: economic utility,sample size,and assessment of carcass transport strategies

Economic utility indices provide a means of interpreting butchery and transport decisions reflected in the relative abundance of skeletal elements. Because of destructive taphonomic processes, interpreting skeletal element abundances in terms of carcass transport strategies requires that faunal analysts consider only those elements which accurately reflect their original abundances following human discard. In this study we use resampling techniques to examine the impact of sample size on correlations between high-survival skeletal element frequencies and economic utility in four simulated population assemblages reflecting distinct carcass transport strategies. Correlations alone do not accurately reflect the true relationship between bone abundance and economic utility as particular transport strategies have a tendency to generate high frequencies of Type II errors as sample size decreases. We show that the Shannon evenness index can be used as a quantitative means of distinguishing between bone assemblages characterized by subtle variations in skeletal element abundances. The evenness index can also be used to evaluate whether observed correlations reflect sampling error. Results from our simulations are applied to three published faunal assemblages to evaluate likely carcass transport strategies.     

Burned bone in the Howieson’s Poort and post-Howieson’s Poort Middle Stone Age deposits at Sibudu (South Africa): behavioral and taphonomic implications

Despite a growing awareness of the wide range of information that can be provided by detailed analyses of burned bone from archaeological contexts, such analyses are still relatively uncommon. This paper focuses on the behavioral and taphonomic implications of burned bone from the Middle Stone Age (MSA) site of Sibudu Cave (South Africa), reporting on the analysis of a large sample (>377,000 fragments) of bone recovered from the Howieson’s Poort (HP) and post-HP MSA deposits at the site. Faunal remains were initially sorted into burning categories based on changes in color; microscopic analyses focused on the optical properties of the bone matrix (degree of preservation of the bone structure, reflectance and fluorescence) indicated that the color is a valid indicator of thermally altered bone in the Sibudu assemblage. The association of burned bone with hearths, the intensity of burning damage, and the sheer quantity of thermally altered bone suggests that the bone was not burned primarily as a result of natural fires. We propose that the high incidence of burned bone primarily reflects two types of site maintenance activities: first, the discarding of bone into fire as a means of disposing of food waste (as also argued by Cain [2005, Using burned animal bone to look at Middle Stone Age occupation and behavior. J. Archaeol. Sci. 32, 873–884], for a smaller sample of material from the post-HP and late MSA deposits at the site), and second, the incidental burning of bone on/near the surface during the periodic burning of plant-based bedding. In considering the taphonomic implications of the burned bone, we demonstrate that calcined bone is in fact more heavily fragmented than unburnt or moderately burned bone. Furthermore, cortical preservation was negatively correlated with the intensity of burning damage, which has implications for the study of surface modifications. These results indicate the importance of conducting thorough taphonomic analyses prior to making comparisons between units that show differing degrees or intensities of burning damage.     

Assessing the variability in taphonomic studies of modern leporid remains from Eagle Owl (Bubo bubo) nest assemblages: the importance of age of prey

The Eagle Owl (Bubo bubo) is an important leporid remains accumulator at archaeological sites. Taphonomical studies of modern leporid remains from nest assemblages of this nocturnal raptor aim to establish the main characteristics that define the taphonomic signature of Eagle Owls in order to distinguish them from that of other leporid predators, namely diurnal raptors, terrestrial carnivores and humans. However, analyses carried out so far have shown that the identification of diagnostic features of Eagle Owls leporid nest accumulations is not a straightforward issue – variability has been observed. Age and size of prey are pointed among others as accountable factors but little research has been done on the study of these variables. Here we present the analysis of two samples of modern leporid remains recovered from Eagle Owls nests with the aim of contributing new data to this subject. The high presence of juvenile individuals in both samples enables us to assess anatomical representation, breakage and digestion patterns of immature leporid remains and also to compare them with other assemblages richer in adult prey. Results show that the main characteristic features noted in previous works which recognise Eagle Owls as agents of leporid bones accumulations in the fossil record, are not significantly affected by the age of prey. Less variability than originally thought occurs which means other variables need to be further investigated.     

Stability of phytoliths in the archaeological record: a dissolution study of modern and fossil phytoliths

Opaline phytoliths are important microfossils used in archaeological and ecological research. Relatively little is known about the stability of phytoliths after burial. Under alkaline pH conditions they can dissolve, and mechanical disturbances can cause a loss of their more delicate appendages. Here we present an experimental study of phytolith stability (combination of solubility and abrasion). Modern and fossil phytoliths were extracted from wheat using new methods to minimize dissolution, and by burning in an oven. These assemblages were placed in a solution buffered to pH 10 and maintained under constant temperature and shaking conditions. The silicon concentrations in the solution were monitored once a week for 5 weeks. The phytolith morphologies in each assemblage were determined at the outset of the experiment and after 5 weeks. The results show that there are differences in stability between various assemblages. Modern inflorescence wheat phytolith assemblages are more unstable than those from leaves/stems. Burnt assemblages are less stable than unburnt assemblages, and a fossil phytolith assemblage about 3000 years old is more stable than the modern wheat assemblages. The results also show that individual phytolith morphotypes have different stabilities, and as a result of dissolution and abrasion, some morphotypes may resemble others. This study further shows that archaeological and/or paleo-environmental interpretation of phytolith assemblages may change with the assemblage’s state of preservation.     

Variation in tooth mark frequencies on long bones from the assemblages of all three extant bone-collecting hyaenids

Tooth mark frequencies on long bones are examined from the assemblages of all three extant bone-collecting hyaenids. Comparisons are made with a recent study examining tooth mark frequencies and possible sources of variation from a single spotted hyaena (Crocuta crocuta) assemblage (Faith, J.T., 2007. Sources of variation in carnivore tooth-mark frequencies in a modern spotted hyena (Crocuta crocuta) den assemblage, Amboseli Park, Kenya. Journal of Archaeological Science 34 (10), 1601–1609). The factors that may influence tooth mark frequencies are fragment size, fragments from different sized animals, region of skeletal element and bone density. All four factors are examined in the present study and compared across species and with previous results. The results indicate that there is a great deal of variation in tooth mark frequencies not only between the species but also from the same species.     

Identifying sword marks on bone: criteria for distinguishing between cut marks made by different classes of bladed weapons

Swords have been one of the major weapons used in violent conflicts for much of human history. Certain archaeological situations, especially those dealing with the recovery and analysis of battle casualties, may raise questions about what type(s) of bladed weapon was used in a particular conflict (e.g., the battle of Kamakura, Japan, AD 1333; the battle of Wisby, Sweden, AD 1361; the battle of Towton, England, AD 1461). Little work has been done, however, on developing criteria to differentiate sword cut marks from other types of cut marks, or to distinguish between marks created by different sword types. To develop such criteria, bovine tibiae (n = 7) were struck using six different types of bladed weapon and the resulting marks (n = 92) were analyzed. Eight traits describing the morphology of the cut mark – such as shape, the presence and unilateral/bilateral state of flaking and feathering, the presence of bone shards, associated breaks, etc. – are defined and related to blade type used. Sword marks were found to be easily distinguishable from knife marks. The variation in marks made by different sword types is significantly correlated with differences in blade weight (p < 0.0001), grip (p < 0.0113), and sharpness (p ≤ 0.0179). The criteria and analyses developed and implemented in this study will be of use to researchers in forensics and osteoarchaeology who want to infer bladed weapon type from marks on bones.     

A note on the use of temporal frequency distributions in studies of prehistoric demography

Temporal frequency distributions of archaeological sites and radiocarbon dates are commonly used as proxies for prehistoric population levels based on the assumption that more people create a stronger archaeological signal. While this assumption is certainly correct, we question whether relative frequencies of sites or dates observed from prehistoric contexts are necessarily linked to human demography. In this paper, we demonstrate that the typical positive curvilinear frequency distributions observed in archaeological contexts also regularly occur in paleontological and geological contexts and are thus likely caused by the operation of time-dependent destructive processes, what we call “taphonomic bias.” Using a simple model, which assumes a constant rate of site loss over time, we show how taphonomic bias can produce positive curvilinear frequency distributions through time even in cases of population stasis, decline, and fluctuation. We conclude that caution must be used when attempting to infer demographic trends from frequency distributions alone.     

Methodological problems in the analysis of fossil non-artifactual wood assemblages from archaeological sites

The analysis of fossil wood fragments is often undertaken in relation to the archaeological excavation of a site. However, such analysis does not yet appear to have the strong methodological foundation that the investigation of many other classes of palaeoenvironmental evidence (e.g. seeds and pollen) have. Consequently, it is difficult to evaluate the value of fossil wood analysis at an archaeological site. Using data regarding non-artifactual wood assemblages at one site in southern Scotland, the relative merits of possible analysis are described and discussed. The results from such analyses tend to fall into two broad groups: (I) those of relatively high reliability, and (2) those of relatively low reliability. The results in the former group are often based on moderately secure methodology and tend to provide relatively non-interpretative information (e.g. species lists). On the other hand, those in the latter group are more often based on insecure interpretive methodology and provide relatively more stimulating information, such as evidence for prehistoric woodland management. There are many reasons for this situation, and these are discussed. In conclusion, it is argued that to increase the reliability of results in the second group (in particular), a full understanding of the taphonomy of non-artifactual fossil wood assemblages is needed, and that once this is available attention can then be paid, as elsewhere in environmental archaeology, to the problems of providing statistically valid samples for analysis.     

What goes in does not always come out: The impact of the ruminant digestive system of sheep on plant material,and its importance for the interpretation of dung-derived archaeobotanical assemblages

Abstract

On archaeological sites where livestock dung was a major fuel source, plant material that survives digestion intact may well be preserved in the remnants of dung-fuelled fires. Preserved plant remains which were derived from dung relate to the diet of animals, and thus provide a way of investigating the agro-pastoral economies of the past. In order to improve our understanding of the taphonomic processes to which plant material is exposed to during digestion, we applied archaeobotanical methods to the analysis of dung from sheep fed a known diet of cereal and wild plant material. Two clear patterns emerge from these investigations. First, cereal material (grain or chaff) survives digestion poorly and was rarely found in the dung analysed. Second, large proportions of seeds of various wild species survive digestion in an identifiable form, probably due to their small size and/or protective coating. These findings are crucial for reliable interpretation of dung-derived plant material in archaeological settings.     

Differentiating bamboo from stone tool cut marks in the zooarchaeological record,with a discussion on the use of bamboo knives

The archaeological record of Southeast Asia is marked by a relative lack of Acheulian assemblages compared with the rest of the Old World. Suggestions that prehistoric human populations in this area relied instead on a non-lithic technology based on bamboo have not been supported by archaeological evidence. To provide a diagnostic means of assessing prehistoric use of bamboo, cut marks were experimentally produced on bone using chert tools and bamboo knives. A scanning electron microscope (SEM) examination revealed morphological differences in cut marks produced by the two materials that allow identification of bamboo knife cut marks on faunal materials. Such evidence, if found in Pleistocene through early Holocene archaeological sites in Southeast Asia, would indicate early human reliance on bamboo technology.     

Explaining prehistoric variation in the abundance of large prey: A zooarchaeological analysis of deer and rabbit hunting along the Pecho Coast of Central California

Three main hypotheses are commonly employed to explain diachronic variation in the relative abundance of remains of large terrestrial herbivores: (1) large prey populations decline as a function of anthropogenic overexploitation; (2) large prey tends to increase as a result of increasing social payoffs; and (3) proportions of large terrestrial prey are dependent on stochastic fluctuations in climate. This paper tests predictions derived from these three hypotheses through a zooarchaeological analysis of eleven temporal components from three sites on central California’s Pecho Coast. Specifically, we examine the trade-offs between hunting rabbits (Sylvilagus spp.) and deer (Odocoileus hemionus) using models derived from human behavioral ecology. The results show that foragers exploited a robust population of deer throughout most of the Holocene, only doing otherwise during periods associated with climatic trends unfavorable to larger herbivores. The most recent component (Late Prehistoric/Contact era) shows modest evidence of localized resource depression and perhaps greater social benefits from hunting larger prey; we suggest that these final changes resulted from the introduction of bow and arrow technology. Overall, results suggest that along central California’s Pecho Coast, density independent factors described as climatically-mediated prey choice best predict changes in the relative abundance of large terrestrial herbivores through the Holocene.     

Charcoal scarcity in Epigravettian settlements with mammoth bone dwellings: the taphonomic evidence from Mezhyrich (Ukraine)

Fuel management during the Paleolithic periods is an important issue to understand past human subsistence. Numerous Palaeolithic sites relate an abundance of burnt bones in hearths and an absence or scarcity of wood charcoals, which leads studies to focus on burnt bone remains and the use of bones in hearths. Few works take into account the micro-residues of wood charcoals which can still be present in hearth areas and excavated sediments. We studied the Epigravettian site with mammoth bone dwellings of Mezhyrich (Ukraine) previously characterized by its high content of burnt bones and an “absence” of wood charcoal during the so-called mammoth steppe. The presence or absence and proportions of both wood charcoals and burnt bones were quantified in macro-, meso- and microscale sediment size fractions by an image analysis method. Our results show that excavations during field-works at Mezhyrich give only a partial image of the original anthracological record and that most charcoal materials are lost with standard archaeological and anthracological approaches. The scarcity of charcoals in this site was possibly due to an important mass reduction accentuated by the addition of bones in hearths. By applying our protocol we recovered a significant amount of wood charcoals which provides the first ¹⁴C dates from charcoals at Mezhyrich. Numerous charcoals are identified contributing subsequent information about vegetation, environment and burning practices. They indicate, by comparison with pollen data already collected, the presence of forest patches in a mammoth steppe landscape, which might have influenced the collecting behavior of Epigravettian populations.     

Autochthony and orientation patterns in Olduvai Bed I: a re-examination of the status of post-depositional biasing of archaeological assemblages from FLK North (FLKN)

Recent excavations at FLK North (Olduvai Gorge, Tanzania) have produced new information on the orientation of archaeological materials at various levels of the site. This information includes the uniform distribution of material azimuths, which contrasts with previous inferences of highly patterned orientations of materials in the Bed I archaeological sites. Those previous inferences of patterned material orientations are based on Mary Leakey's 50-year-old drawings of artifact and fossil bone distribution, but are not verified by our precise measurements of archaeological objects made in situ. Nor do those previous results agree with the general lack of geological, geomorphological, and/or taphonomic data that would indicate significant post-depositional movement of archaeological materials in the sites. We argue here that Leakey's drawings are incomplete (only portions of each assemblage were drawn) and inaccurate in their representation of the original locations, shapes and orientations of most archaeological specimens. This argument is supported by several important mismatches in object representations between a photograph taken of a small portion of the FLK 22 Zinjanthropus site floor before the removal of the archaeological items, and the sketch of the same area drawn by Leakey. Thus, we conclude that primary orientation data of excavations (i.e., direct measurements taken from items) generated prior to object removal are the only valid indicators of the relative isotropy or anisotropy of these important paleoanthropological assemblages.     

The effect of a top predator on kangaroo abundance in arid Australia and its implications for archaeological faunal assemblages

The dingo has received considerable attention in the Australian archaeological literature as an agent of bone fragmentation and accumulation. Dingoes have also been studied with respect to their commensal relationship with Aboriginal people. Study has not been directed, however, to the meta-role of dingoes as prey regulators that suppress kangaroo abundance, and the subsequent impact on human subsistence that direct competition between dingoes and humans over the same animal resources could have produced. This study presents data gathered in two adjacent cultural landscapes defined by human land use, one with dingoes and one without dingoes – to illustrate the archaeological effect that dingoes may have had on human economic systems by suppressing kangaroo abundance. Live kangaroos and kangaroo skeletal remains were on average 14-fold and 32-fold more abundant in the absence of dingoes, and contemporary commercial kangaroo harvesting and sheep grazing were restricted to areas where dingoes were absent. Given the marked effects that dingoes have on contemporary kangaroo abundance and the human economy, we argue that dingoes likely shaped the human economy in the past through human–dingo competition for the same limited resources. Evidence for competition between humans and dingoes could be investigated in the archaeological record by comparing the relative frequency of prey of different body sizes, as well as the degree of fragmentation of kangaroo skeletal elements, before and after the arrival of dingoes.     

Testing heterogeneity in faunal assemblages from archaeological sites. Tumbling and trampling experiments at the early-Middle Pleistocene site of Gesher Benot Ya’aqov (Israel)

The current paper reports an experimental case study to test the heterogeneity of faunal assemblages from the Early-Middle Pleistocene Layers V-5 and V-6 of the Gesher Benot Ya’aqov Acheulian site (Israel). Tumbling and trampling experiments were initiated to gain qualitative insight into processes of bone modification and to assess the timing of the biostratonomic chronology, as it was assumed that both mechanisms were responsible for the formation of striations documented on the bone surfaces from the site. The tumbling experiments mimicked sediment movement in a calm lacustrine shoreline environment whereas the trampling experiments investigate the role of animal/hominin activities in dry, muddy and wet environments. Models for the internal operational sequence of an abrasional process due to uni- and multidirectional water movement and of a trampling scenario are presented. These models are used for the interpretation of the fauna from Gesher Benot Ya’aqov.     

Deciphering bone depositional sequences in caves through the study of manganese coatings

The presence of black-coloured bones in caves has been sometimes associated to the use of fire by humans, but more frequently the agent responsible for black colour is the natural deposition of manganese oxides. Manganese coatings were not usually studied once human action was discarded. However, they can provide valuable information about the origin and the sequence of formation of a palaeontological or archaeological deposit. In this paper, we present a quantitative and qualitative study of the manganese coatings that affect most of the bones recovered in the palaeontological site of Liñares cave (NW of Iberian Peninsula) together with other taphonomic marks. The manganese coatings are superimposed on other features previously existing on the surface of the bones. In turn, the coatings can be affected by other agents that modified them totally or partially. The combined interpretation of the different taphonomic marks provides us with valuable information on the sequence where the different taphonomic processes were produced, as for example the intervention of carnivores in the disarticulation of some elements before the burial, the preservation of anatomic connections until after the burial of the carcasses, and the existence of reworking processes in some parts of the infill.