A new experimental study on percussion marks and notches and their bearing on the interpretation of hammerstone-broken faunal assemblages

Preliminary experiments on bone breakage have shown the potential utility of quantifying some of its diagnostic features (percussion marks, percussion notches) for taphonomic inferences about human and carnivore involvement in bone breakage in faunal assemblages. The present study increases the range of experiments undertaken to understand the identification of hammerstone percussion (dynamic loading) and its differences from carnivore bone breakage through tooth pressure (static loading). This study contributes to a better understanding of frequencies of percussion marks, uncovers and quantifies those percussion marks that lack key diagnostic features to be identifiable and that could be mistaken with carnivore tooth marks, quantifies notch types, shows different size ranges for notches on bones from small and large fauna than previously reported, quantifies the proportion of notches bearing percussion marks, and introduces new size data for percussion (impact) flakes and percussion marks. Furthermore, all these variables have been applied to a dual experimental set: one experiment using non-modified hammerstones and another based on the use of modified hammerstones. Results vary considerably according to hammerstone type. Some of these taphonomic variables increase the range of equifinality when identifying marks and notches created by different human and non-human agents. This calls for further caution when using isolated variables and features rather than a holistic approach to make taphonomic inferences.     

Changing patterns of carnivore modification in a landscape bone assemblage, Amboseli Park, Kenya

This study compares the landscape-scale taphonomic signal of carnivore modification to the surficial bone assemblage in Amboseli Park, Kenya as it was in 1975 and 2002–2004. Change in predator abundances over time provides a means of assessing the taphonomic signal of carnivore-mediated bone consumption and destruction under differing ecological conditions and varying levels of conspecific competition for resources. The landscape assemblage indicates taxonomic variation in the patterning of carnivore modification to ungulates of different size classes as well as within equivalent size classes. Analyses of long bone elements indicate that the differential destruction of limb ends and the strength of the correlation between limb end abundance and bone mineral density provide an indication of the intensity of carnivore modification to a faunal assemblage. The ability to infer levels of carnivore modification based on limb elements can provide faunal analysts with the tools to determine whether the taphonomic signals in the fossil record relate to carnivore modification, hominin transport of appendicular elements, or both.     

Pits and pitfalls: taxonomic variability and patterning in tooth mark dimensions

Archaeologists use experimentally derived tooth mark frequencies, locations, and size data to infer (a) the extent of carnivore involvement in the formation and modification of faunal assemblages, (b) the size classes of predators marking those assemblages, and (c) whether hominins accessed fleshy or defleshed carcasses (Blumenschine and Pobiner, 2007; Dominguez-Rodrigo et al., 2007). These inferences are often debated in part because frequency counts can vary widely among observers and because the carnivore taxa for which tooth mark dimensional data are available are limited. This study contributes to the body of actualistic/experimental tooth mark data and presents a methodology for collecting these data. We offer a greatly simplified method that may encourage others to collect and quantify tooth mark dimensions. We present dimensional data from feeding experiments with 16 omnivore and carnivore species of known age and mass, ranging in size from skunks to tigers, significantly expanding the taxonomic and size range of carnivores for which we have tooth pit data. Our results demonstrate considerable, but not complete, overlap in tooth pit dimensions among size, class, and taxon. Tooth mark dimensions on epiphyses and metaphyses were relatively strongly correlated with body mass, whereas diaphyseal tooth marks exhibited the weakest correlation. Human consumption of animal tissue produced tooth marks comparable in size to medium felids and small canids, suggesting the possibility that some tooth marks on Early Stone Age (ESA) faunal assemblages could, as suggested by Oliver (1994), result from small carnivore and/or hominin consumption.     

Why are cut mark frequencies in archaeofaunal assemblages so variable? A multivariate analysis

Cut mark frequencies in archaeological faunal assemblages are so variable that their use has recently created some skepticism. The present study analyses this variability using multivariate statistics on a set of 14 variables that involve differential skeletal element representation, fragmentation processes, carnivore ravaging impact, carcass size and tool type. All these variables affect the resulting cut mark frequencies reported in archaeological sites. A large sample of archaeofaunal assemblages has been used for this study. It was concluded that the best estimator of cut mark frequency in any given assemblage is the percentage of cut-marked long bone specimens (probably due to its better preservation than other anatomical areas), which is determined by fragmentation and carnivore ravaging. Carcass size and tool type also play a major role in differences in cut mark frequencies. Fragmentation is also a key variable determining the abundance of cut-marked specimens. It is argued that general cut mark percentages are of limited value, given the number of variables that determine them, and that a more heuristic approach involves quantifying cut marks in a qualitative manner.     

Ascertaining an agent: using tooth pit data to determine the carnivore/s responsible for predation in cases of suspected big cat kills in an upland area of Britain

The identification of the involvement of a particular carnivore in the modification of bone assemblages concerns a number of fields of research including archaeological and palaeontological enquiry. Taphonomy provides a methodology by which bone assemblages can be analysed and interpreted and this is more often undertaken with archaeological or palaeontological assemblages. A taphonomic analysis is undertaken here in order to determine the perpetrator of predation attacks on domestic stock from a modern-day setting. Recently reported techniques using tooth marks preserved on bone surfaces made by known carnivores are successful at determining some class sizes of predators and are used here to determine the perpetrator(s). Although a class size of carnivore is readily identified by this methodology, a particular carnivore taxon is not. Tooth morphology and dental configuration are reported here as better criteria for identifying a particular taphonomic agent. Tooth pit dimensions are used here to identify the class size of carnivores involved, and tooth morphology and cusp spacing to suggest a medium sized felid and fox as taphonomic agents. The identification of the medium-sized felid may support observations and reports of alleged “big” cat kills in the area. The study has important implications for the interpretation of fossil sites where felids may have been involved in the modification of animal carcasses but are archaeologically invisible in terms of their fossil remains.     

Sources of variation in carnivore tooth-mark frequencies in a modern spotted hyena (Crocuta crocuta) den assemblage,Amboseli Park,Kenya

Distributions and frequencies of carnivore tooth-marks on large mammal long-bone fragments are commonly used to infer the timing of hominin and carnivore access to prey resources in archaeofaunal assemblages. The strength of these inferences, however, is limited by a broad and currently inexplicable range of tooth-mark frequencies across experimental and archaeological assemblages. Controlling for this variation first requires that the sources be identified. Several sources of variation are examined here in an analysis of tooth-marked bone recovered from a modern spotted hyena (Crocuta crocuta) den assemblage in Amboseli Park, Kenya. Results indicate that tooth-mark frequencies: (1) depend on fragment size, (2) vary across mammals of different size classes, (3) are highly variable across equivalent portions of different long-bone elements, and (4) on certain long-bone portions are correlated with bone density and can be depressed in archaeological assemblages subjected to density-mediated attrition. Stronger inferences based on tooth-mark frequencies will require that such variation be taken into consideration, and methods for doing so are suggested.     

Identifying the Involvement of Multiple Carnivore Taxa with Archaeological Bone Assemblages

Information on the number of carnivore taxa that were involved with archaeological bone assemblages is pertinent to questions of site formation, hominid and carnivore competition for carcasses and the sequence of hominid and carnivore activity at sites. A majority of early archaeological bone assemblages bear evidence that both hominids and carnivores removed flesh and/or marrow from the bones. Whether flesh specialists (felids) or bone-crunchers (hyaenas), or both, fed upon the carcasses is crucial for deciphering the timing of hominid involvement with the assemblages. Here we present an initial attempt to differentiate the tooth mark signature inflicted on bones by a single carnivore species versus multiple carnivore taxa. Quantitative data on carnivore tooth pits, those resembling a tooth crown or a cusp, are presented for two characteristics: the area of the marks in millimetres, and the shape as determined by the ratio of the major axis to the minor axis of the mark. Tooth pits from bones modified by extant East African carnivores and latex impressions of tooth pits from extinct carnivore species are compared to those in the FLK Zinjanthropus bone assemblage. Data on tooth mark shape indicate greater variability in theZinj sample than is exhibited by any individual extant or extinct carnivore species in the comparative sample. Data on tooth mark area demonstrate that bone density is related to the size of marks. Taken together, these data support the inference that felids defleshed bones in the Zinj assemblage and that hyaenas had final access to any grease or tissues that remained.     

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.     

Experimental study of cut marks made with rocks unmodified by human flaking and its bearing on claims of ∼3.4-million-year-old butchery evidence from Dikika, Ethiopia

In order to assess further the recent claims of ∼3.4 Ma butchery marks on two fossil bones from the site of Dikika (Ethiopia), we broadened the actualistic-interpretive zooarchaeological framework by conducting butchery experiments that utilized naïve butchers and rocks unmodified by human flaking to deflesh chicken and sheep long limb bones. It is claimed that the purported Dikika cut marks present their unexpectedly atypical morphologies because they were produced by early hominins utilizing just such rocks. The composition of the cut mark sample produced in our experiments is quite dissimilar to the sample of linear bone surface modifications preserved on the Dikika fossils. This finding substantiates and expands our earlier conclusion that—considering the morphologies and patterns of the Dikika bone surface modifications and the inferred coarse-grained depositional context of the fossils on which they occur—the Dikika bone damage was caused incidentally by the movement of the fossils on and/or within their depositional substrate(s), and not by early hominin butchery. Thus, contrary to initial claims, the Dikika evidence does not warrant a major shift in our understanding of early hominin behavioral evolution with regard to carcass foraging and meat-eating.     

Factors affecting Early Stone Age cut mark cross-sectional size: implications from actualistic butchery trials

Early Stone Age cut marks are byproducts of hominins' tool-assisted animal carcass consumption and provide a potential avenue of inference into the paleoecology of hominin carnivory. If diagnostic cut mark characteristics can be linked to flake and core tool use or the completion of distinct butchery actions, it may be possible to infer ancient tool preferences, reconstruct the consumption of specific muscular tissues, and illuminate landscape-scale stone resource use. Recently, diagnostic morphological criteria including cut mark width and depth have been used to identify marks made by different classes of experimental and archaeological stone tools (Bello, S.M., Parfitt, S.A., Stringer, C., 2009. Quantitative micromorphological analyses of cut marks produced by ancient and modern handaxes. Journal of Archaeological Science 36: 1869–1880; de Juana, S., Galan, A.B., Dominguez-Rodrigo, M., 2010. Taphonomic identification of cut marks made with lithic handaxes: an experimental study. Journal of Archaeological Science 37: 1841–1850; Dominguez-Rodrigo, M., de Juana, S., Galan, A. B., Rodriguez, M., 2009. A new protocol to differentiate trampling marks from butchery cut marks. Journal of Archaeological Science 36: 2643–2654). The work presented here adds to this experimental butchery database by using measurements of cut mark cross-section taken from bone surface molds to investigate how stone tool characteristics including flake versus core tool type, edge angle, and tool weight, influence cut mark width and depth, ultimately testing whether cut mark size is a useful indicator of tool identity. Additionally, these experiments investigate the influence of contextual factors, including butchery action, carcass size, and bone density on cut mark size. An experienced butcher used replicated Oldowan flakes and bifacial core tools in experimental trials that isolated skinning, bulk and scrap muscle defleshing, and element disarticulation cut marks on goat and cow skeletons. This sample explores cut mark traces generated under realistic butchery scenarios and suggests the following results: 1) Core and flake tools were equally efficient at completing all butchery tasks in size 1 and 3 bovid carcasses. 2) Samples of cut mark width and depth produced by core and flake tools were similar and cut marks could not be accurately classified to a known tool type. 3) Skinning and disarticulation activities produced significantly wider and deeper marks than defleshing activities. 4) Cut marks on cows tended to be wider and deeper than those on goats. 5) Cut mark width is negatively correlated with bone density when carcass size and bone portion are taken into consideration. These results suggest that a general quantitative model for inferring tool type or edge characteristics from archaeological cut mark size is not warranted.     

Taphonomic resolution and hominin subsistence behaviour in the Lower Palaeolithic: differing data scales and interpretive frameworks at Boxgrove and Swanscombe (UK)

The identification of human butchery-signatures on fauna from Lower Palaeolithic sites is well documented and readily identifiable. Such bone surface modifications have the potential to provide not only information about past hominin meat-procurement behaviour but address the wider issue of competition for resources with other carnivore species. To understand and discuss these broader issues both hominin and natural bone surface modifications must be understood and contextualised within a site-specific spatial and temporal framework. This paper presents new results from faunal analysis at two key British Lower Palaeolithic localities: Boxgrove and Swanscombe. It illustrates that different depositional environments and excavation histories have resulted in different scales and resolutions of available data and hence in varying interpretive potentials. At Swanscombe the archaeological record has been disturbed by both fluvial activity and excavation history providing a coarser-grained record of anthropogenic behaviour than previously acknowledged. Conversely, at Boxgrove, a finer-grained, higher resolution record of human behaviours has been preserved; this, combined with both an extensive and intensive excavation strategy, has allowed for a broader discussion of hominin landscape use, resource competition and meat-procurement behaviour. This paper highlights that assessing the specific depositional environment at each site is crucial to understanding Palaeolithic faunal assemblage formation and, consequently, the available data-resolution and behavioural interpretation.     

Examining criteria for identifying and differentiating fossil faunal assemblages accumulated by hyenas and hominins using extant hyenid accumulations

Numerous authors have put forth criteria for distinguishing between assemblages collected by hyenas and hominins. Of the seven most recognised criteria used to distinguish hyenid from hominin assemblages, it has recently been suggested that four be rejected and three retained. The four rejected criteria are: an excessive proportion of horns and horn cores in hyena accumulated assemblages; the absence of small, hard, compact bones; mortality profiles; and the ratio of cranial bones to postcranial bones. The three criteria previous researchers suggested be retained are: a carnivore MNI ratio of ≥20%; an abundance of cylinder fragments; and hyena‐inflicted damage upon the bones. In this examination of over 27,000 faunal remains associated with all three species of extant bone‐collecting hyenids from four countries and two continents, six of the seven previously established criteria and reconsiderations of criteria have been evaluated. The results of the present study indicate that of the six criteria examined, none, as written, are indicative of hyenid activity on bone assemblages of unknown origin. Copyright © 2008 John Wiley & Sons, Ltd.     

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.     

Neotaphonomic measures of carnivore serial predation at Ngamo Pan as an analog for interpreting open-air faunal assemblages

Here I present a neotaphonomic account of natural bone accumulations that have resulted from carnivore serial predation at Ngamo Pan, a vast complex of seasonal water holes located in Hwange National Park, Zimbabwe. Reconstructing the taphonomic histories of faunal assemblages from open-air archaeological sites is burdened with a host of interpretive complications, and this study is offered as a referential means for evaluating instances where stone tools and bone accumulations are associated in apparent archaeological contexts. While the presence of stone tools implies some involvement on the part of humans, open-air sites near water would also have served as prime locations for serial predation by large carnivores to ambush prey—a situation that, over time, can mimic archaeological bone accumulations. The taphonomic and zooarchaeological signatures of carnivore serial predation at Ngamo Pan show marked similarities with the open-air faunal accumulation from Kalkbank, a late Pleistocene site in Limpopo Province, South Africa, located along the margins of a relict pan. Many potential archaeological sites within the interior of southern Africa dating to the Middle Stone Age are known from open-air settings near permanent or ephemeral bodies of water, and the ability to decipher between hominin and non-hominin carnivore involvement with bone accumulations is paramount in determining the hunting and scavenging behaviors of our early ancestors. As much of our understanding of hominin subsistence during the Middle Stone Age is drawn from coastal cave locations, this study is intended to encourage a broadening of our perspective on the taphonomic histories of faunal accumulations dating to the Middle Stone Age by incorporating supplementary evidence provided by these open-air sites.     

Taphonomy of ungulate ribs and the consumption of meat and bone by 1.2-million-year-old hominins at Olduvai Gorge,Tanzania

The phenomenon of equifinality complicates behavioral interpretations of faunal assemblages from contexts in which Pleistocene hominins are suspected bone accumulators. Stone tool butchery marks on ungulate fossils are diagnostic of hominin activities, but debate continues over the higher-order implications of butchered bones for the foraging capabilities of hominins. Additionally, tooth marks imparted on bones by hominins overlap in morphology and dimensions with those created by some non-hominin carnivores, further confounding our view of early hominins as meat-eating hunters, scavengers or both. We report on the manual/oral peeling of cortical layers of ungulate ribs as taphonomically diagnostic of hominoid/hominin meat- and bone-eating behavior that indicates access to large herbivore carcasses by hominins at the site of BK, Olduvai. Supporting these inferences, we show that certain types of rib peeling damage are very rare or completely unknown in faunas created by modern carnivores and African porcupines, but common in faunas modified by the butchery and/or consumption activities of modern humans and chimpanzees, during which these hominoids often grasp ribs with their hands, and then used their teeth to peel strips of cortex from raggedly chewed ends of the ribs. Carnivores consume ungulate ribcage tissues soon after kills, so diagnostic traces of hominin butchery/consumption on ribs (i.e., peeling and butchery marks) indicate early access to ungulate carcasses by BK hominins. Tooth marks associated with the peeling and butchery marks are probably hominin-derived, and may indicate that it was not uncommon for our ancestors to use their teeth to strip meat from and to consume portions of ribs. Recognition of rib peeling as a diagnostic signature of hominoid/hominin behavior may also aid the search for pre-archaeological traces of hominin meat-eating.     

A study of dimensional differences of tooth marks (pits and scores) on bones modified by small and large carnivores

The use of tooth mark sizes to infer carnivore types when analyzing the modification of faunal assemblages has been criticized on the base of intense overlap in tooth mark size among differently sized carnivores. The present study analyzes this overlap and presents some critical explanations for it. This work is based on the largest collection of tooth pit dimensional data collected to date for some of the most relevant carnivore types. The study empirically shows that small and large carnivores can be clearly differentiated when using tooth pit size, with a higher discrimination when using tooth marks on dense shafts than on cancellous ends. It is argued that most previous studies of tooth mark sizes have reproduced a higher overlap probably because sample sizes were small, and experiments were carried out using small carcasses (which require a smaller bite force) or for a combination of factors.     

Carnivore competition, bone destruction, and bone density

In carnivore-modified archaeofaunal assemblages it is important to evaluate the degree to which carnivores have overprinted hominin behavioral signals. To examine the signals of increased competition for discarded bone, we present controlled experimental data on 33 simulated archaeological sites subjected to secondary consumption by spotted hyenas. We examine the relationship between competition, as measured by controlled numbers of hyenas and limb bones, and resultant levels of destruction and correlations between long-bone portion survivorship and bone density. Our results indicate that levels of destruction are equivalent regardless of the numbers of hyenas or long-bones included in the experimental assemblages. Correlations between long-bone epiphyseal and near-epiphyseal portions and bone density, however, do provide an indication of the level of competition. Results from the experimental study are used to highlight divergent levels of carnivore competition for hominin-discarded bone at the Plio-Pleistocene localities FLKN-Zinjanthropus and FLKN levels 1–2 from Olduvai Gorge, Tanzania.     

FOCUS: on the use of the petrous bone for estimating cranial abundance in fossil assemblages

Low representation of braincase bones in zooarchaeological assemblages suggests that skulls have been intensively processed by Levantine Epipalaeolithic foragers; most cranial elements are often unidentifiable and are considered poor candidates for quantifying crania. In contrast, the petrous bone is usually found complete, and was found to be easily identifiable to body size category. Use of the petrous bone in fossil assemblages analyses leads to better estimation of the occurrence of cranial elements, and thus of skeletal part representation. We therefore suggest use of the petrous bone for detecting bone destruction and selective transport in faunal assemblages.     

Bone surface modifications in zooarchaeology

Cutmarks made by stone tools, conchoidal flake scars from hammerstone percussion, carnivore tooth marks, striations from sedimentary abrasion, and other surface modifications on bones from archaeological sites constitute a crucial body of evidence for investigating the role of human behaviors and of nonhuman taphonomic processes in site formation. This paper describes the various kinds of bone surface modifications produced by humans and by nonhuman processes and assesses the current status of bone surface modification studies with regard to such issues as the need for greater analytical standardization, the selection of instruments for examining bone specimens, tactics for identifying the origins of marks on bones, and strategies for inferring human behaviors.     

Experimental patterns of hammerstone percussion damage on bones: implications for inferences of carcass processing by humans

The common occurrence of hammerstone percussion damage (pits, striae, notches and impact flakes) on the fossil limb bones of ungulates indicates that marrow extraction has been an important component of hominid butchery for over two million years. Beyond this level of basic inference, it would be behaviorally informative if three deeper aspects of marrow harvesting were understood more clearly: (1) whether inter-element patterns of bone fragmentation vary when processing intensity is held constant; (2) whether butcher investment in marrow extraction correlates positively with the number of percussion marks generated; (3) whether taphonomic effectors can be identified based on percussion mark morphology, frequency and placement. Some experimental work has been conducted previously in service of exploring these questions, but we set out here to address them explicitly through the analysis of a large sample of white-tailed deer (Odocoileus virginianus) limb elements fractured by hammerstone percussion. Our results indicate that (1) measures of bone fragmentation, which supposedly reflect processing intensity, are highly contingent on the research question being posed. This stresses the fact that researchers must be explicit in their definition of processing intensity. (2) In addition, hypothesized covariance between number of hammerstone blows and percussion mark frequencies are not met in our sample, corroborating previous conclusions of a lack of covariance between cutting strokes and cutmark frequencies. These results highlight the contingent nature of butchery mark production, and emphasize the need to investigate carcass resource exploitation by posing questions that do not rely on mark frequencies, but instead utilize other zooarchaeological measures. (3) Finally, our results—showing high incidences of impact notches and flakes created by direct anvil contact and “anvil scratches” created by direct hammerstone contact—suggest caution in using specific categories of percussion damage to infer their taphonomic effectors.