Assessing the function of early hominin bone tools

Bone tools from early hominin sites in southern Africa continue to intrigue researchers interested in the development of early human technology and cognition. Sterkfontein, Swartkrans and Drimolen have all yielded bone tools dated to between 1 and 2 Mya associated with numerous Paranthropus robustus and few early Homo remains. The bone tools are described by different authors as implements used to excavate tubers from the ground and termites from their nests, work hides and strip bark from trees. The purpose of this research was to develop a more powerful analytical tool for the study and interpretation of bone surface modifications in general, and early hominin bone tool function(s) in particular. We used an optical interferometer to scan the worn areas of a sample of bone tools from Swartkrans and Drimolen, an ethnographic collection of implements used for defleshing marula fruits, and a set used experimentally to excavate in the ground and in termite mounds. The 3D rendering of archaeological and experimental wear patterns better highlights previously described differences between these patterns, and demonstrates the pertinence of this analytical tool to visually discriminating between different bone modifications. Analysis of selected 2D and 3D roughness variables indicates that the wear pattern on the early hominin bone tools from Drimolen is significantly different from that of tuber digging, very similar to termite foraging, and not unlike marula fruit processing. Marked differences are detected between the Swartkrans and Drimolen wear patterns, which suggests that the tools from these sites may have been used with different motions, in contact with abrasive particles of different size, or in different tasks. Principal component analyses conducted on 2D and 3D variables suggest that early hominin bone tools from southern Africa may have been used to forage for termites, extract tubers in a motion parallel to the tool main axis, process fruits and conduct other, as yet unidentified, tasks.     

Possible evidence of bone tool shaping by Swartkrans early hominids

Ever since Dart (J. Phys. Anthrop. 7 (1949) 1) interpreted certain bones from Makapansgat as tools, scientific consensus has fluctuated as to whether some bone objects from early hominid sites should be interpreted as artefacts, or the result of non-human taphonomic processes, which are known to produce pseudo-bone tools morphologically similar to human modified or used artefacts. Here we present possible evidence of bone tool shaping from Swartkrans (Members 1–3; ca. 1.8–1.0 Mya). Four horncores and the proximal end of an ulna used as tools in digging activities also have facets covered by parallel spindle-shaped striations characteristic of grinding. Identification of these traces as possibly resulting from deliberate shaping or re-sharpening of the bone tools is based on the characterisation of the use-wear pattern and other taphonomic modifications observed on the Swartkrans bone tools. This interpretation is also supported by the study of the remainder of the horncores from Swartkrans, horncores from other southern African Plio-Pleistocene sites (Sterkfontein, Makapansgat, Gondolin), modern horncores affected by pre- and post-mortem modification, ethnographic, LSA, African Iron Age and experimental bone tools shaped by grinding. These data suggest that early hominids had the cognitive ability to modify the functional area of bone implements to achieve optimal efficiency.     

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.     

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.     

Preliminary evidence for seasonal deposition patterns from member 2 of the Swartkrans hominid site,South Africa

Frequencies of specimens in juvenile age classes, based on an analysis of tooth eruption and wear sequences, in specimens of an extinct species of springbok, Antidorcas bondi Wells and Cooke, from Member 2 of the Swartkrans hominid site, suggest that the remains of this animal were deposited during summer months. These indications of seasonal activity may offer support for previous suggestions of annual game movements. Such periodic movements have implications for our understanding of the behaviour patterns of the animals, including perhaps the hominids, which are represented in the assemblages from Swartkrans and other sites in the vicinity.     

Reconsideration of criteria for differentiating faunal assemblages accumulated by hyenas and hominids

Zooarchaeologists have established several criteria for differentiating hominid‐ and hyena‐derived faunal assemblages. In some cases, however, the patterns of skeletal part representation and bone surface modification on which these criteria are ultimately based have been observed in fossil bone assemblages of unknown origin, rather than in modern assemblages of known origin. When the proposed criteria are evaluated within an actualistic framework, only three are able to differentiate between hominid‐ and hyena‐created faunal assemblages. I suggest that only these three criteria—proportions of carnivores to ungulates in the assemblage, the preserved condition of long bone specimens (either as whole cylinders or as splintered shaft fragments), and the types of bone surface modifications—should be retained as important factors in a diagnosis of the ancient bone‐collector. The remaining four criteria—the relative proportion of horn pieces in the assemblage, the relative representation of podial bones, the relative representation of small and large bovid skeletal parts, and bovid mortality profiles—are not relevant or applicable to the problem of differentiating hominid‐ from hyena‐derived faunal assemblages. Copyright © 2002 John Wiley & Sons, Ltd.     

A taphonomic study of the African wild dog (Lycaon pictus)

Carnivore taphonomy has been traditionally used for the interpretation of archaeological sites in order to discriminate human-generated or modified from non-anthropic bone assemblages. In most of this actualistic research, the focus has mainly been placed on hyenas and felids, neglecting other carnivores. This paper analyzes the taphonomic impact of the African wild dog (Lycaon pictus) on equid bones and compares it with the bone modification patterns produced by other canids, such as wolves (Canis lupus) in order to compare medium-/large-sized canid variability on bone modification patterns and elaborate a referential framework which could be feasibly applied to the zooarchaeological record to detect canid intervention on archaeological assemblages in the past.     

Avian taphonomy: observations at two Magellanic penguin (Spheniscus magellanicus) breeding colonies and their implications for the fossil record

Actualistic studies on vertebrate taphonomy have centred on mammals, and to a much lesser extent on flying birds. Members of the Spheniscidae are anatomically specialized making it problematic to make direct inferences from previous taphonomic work. Modern bone assemblages from two Spheniscus magellanicus breeding colonies on the southern Atlantic coast of continental Patagonia, Argentina, were surveyed on foot along linear transects, and features were determined that are useful in interpreting the fossil record. Present day bone accumulations have specific properties resulting from penguin anatomy and osteology as well as from the composition of the vertebrate community and regional environmental conditions. Most salient are the high spatial density of bones, the dominance of Spheniscidae remains over those of other vertebrates, the high percentage of disarticulated bones, the predominance of limb bones, the low frequencies of carnivore bone modifications, and the abundance of fractured bones. Many of these features observed in the modern assemblages can be identified in fossil avian bone deposits.     

Middle Stone Age pièces esquillées from Sibudu Cave,South Africa: an initial micro-residue study

In this paper I present the results of a micro-residue study conducted on ten pièces esquillées (scaled pieces) from Sibudu Cave, South Africa. These artefacts are associated with the Howiesons Poort Industry (∼61.7 and ∼64.7 ka years ago at Sibudu), representing part of the later phase of the Middle Stone Age. Until now, it was unclear on what these pieces were used, and whether they were functional. Previous experimental use-wear work tentatively pointed towards bone processing. However, replication work on stone tool production technology suggests that pièces esquillées are merely the by/end-product of bipolar knapping. I used residue analysis on the Sibudu artefacts because this alternative method has the potential to identify if they were used, and if so, illuminate the specific materials the pieces were used on. Although the sample is small, all the pièces esquillées reveal a clear animal processing signal. There are some bone deposits on the utilised edges that may substantiate bone processing, or perhaps a bone hammer was used with them, but additional study, including Later Stone Age artefacts, is needed to assess the feasibility of these observations. It remains possible that the artefacts are core reduced pieces that were subsequently used as tools or simply knapped with a bone hammer.     

The Red Fox (Vulpes vulpes) as an Accumulator of Bones in Cave‐like Environments

Identifying the behavioural patterns of bone collecting animals is a crucial aspect of taphonomic studies. Although many studies have established criteria for identifying animal‐collected or animal‐modified bones, very few papers describe the distinguishing features of fox‐made bone assemblages. The bone assemblage collected in an inactive underground stone mine in Potok‐Senderki (Poland) is diagnostic of a red fox (Vulpes vulpes) den. This site provides an ideal opportunity to develop an understanding of the bone collecting behaviour of red foxes in cave‐like environments. This study showed that bones collected by red foxes are concentrated in clusters. The bones represent a broad spectrum of local fox prey species, with most bones showing the marks of gnawing. Each cluster may contain from <10 to >100 bones. Furthermore, the long axes of the bones in clusters frequently show specific orientation. The analysis of bones at this site might make an important contribution towards the establishment of baseline criteria for the identification and evaluation of fox‐accumulated bone assemblages. Copyright © 2012 John Wiley & Sons, Ltd.     

Taphonomy and zooarchaeology of a high-altitude Upper Pleistocene faunal sequence from Hovk-1 Cave,Armenia

The Caucasus is a key region for the study of hominid evolution and Neanderthal ecology. Taphonomic and zooarchaeological studies of sites from this region are few and only focused on sites at low-to-mid altitude zones with evidence of relatively intensive hominid occupation. This study focused on the taphonomic and zooarchaeological characteristics of a high-altitude site from the Upper Pleistocene – Hovk-1 Cave – looking at diachronic change in both natural and cultural processes which shaped the faunal assemblage. Results best fit a model in which the bones of most large mammals, mainly ungulates (wild goat, Capra aegagrus and red deer, Cervus elaphus) and cave bears (Ursus spelaeus) accumulated naturally through pitfalls, with minimal input from human or carnivore activity. This accumulation is characterized by a high frequency of complete ungulate and carnivore bones, a bear assemblage which is dominated by young-adults and a wild goat assemblage that includes juvenile and young-adult individuals. Our taphonomic reconstruction serves as a point of reference for comparative studies of palaeoenvironments and human subsistence patterns of Middle and Upper Palaeolithic sites in the Caucasus and broadens our perspective on hominid occupation and ecological adaptation in other high-altitude world regions.     

Age profiles of rhino fauna from the Middle Pleistocene Nanjing man site,south China—explained by the rhino specimens of living species

A total of 60 pieces of rhino materials have been identified from the Nanjing Man site. Morphologically, they belong to the species Dicerorhinus mercki. Among the materials, 40 pieces are broken bones, and 20 are isolated teeth or jaw bones (totally comprising 41 tooth units). Among the teeth, 74% are deciduous, most of them attached to jaws. Other isolated teeth are not greatly worn, meaning they were not naturally replaced, so they represent juvenile animals. Because the skeletons are completely isolated and most of them are broken, their death can not be attributed to a natural trap. Therefore, it is very probable that hominid activities were associated with rhinos at this site. Copyright © 2001 John Wiley & Sons, Ltd.     

Early hominid hunting,butchering, and carcass-processing behaviors: Approaches to the fossil record

A major aim of paleoanthropology is to learn what ancient behaviors were related to the acquisition, processing, and consumption of meat and when these behaviors arose. For this reason, studies focusing on purported early hominid hunting and butchery sites are important if rigorous criteria for recognizing such sites are used. Different criteria currently used as evidence of hominid involvement with ancient bones are reviewed and it is concluded that the presence of cutmarks, verified by scanning electron microscope (SEM) inspection, is the most reliable. Successful application of this criterion depends upon a thorough knowledge of the normal variations in microscopic morphology of different types of marks that are found on bones. Therefore, variations in microscopic and gross morphology within and among a large sample of known stone tool cutmarks, carnivore tooth scratches, and rodent gnawing marks are documented. The effects of sedimentary abrasion, as caused by fluvial transport of bones, are also presented. Guidelines are presented for using microscopic criteria to identify unknown marks on fossils and possible applications of this approach are discussed. Further, it is suggested that evidence of hominid carcass-processing activities can be placed into one of three ranked categories of certainty according to the type of data used. Explicitly stating the category and type of evidence used to deduce hominid activities, and by extension to define site types (i.e., butchery, kill, base camp), may improve the clarity of hypotheses about and interpretations of early hominid behaviors.     

Gazelle bone marrow yields and Epipalaeolithic carcass exploitation strategies in the southern Levant

We measure the bone marrow yields of mountain gazelle (Gazella gazella) carcasses to reconstruct gazelle exploitation strategies during the Epipalaeolithic periods in the southern Levant. We present experimentally derived data on the bone marrow content of seven fresh gazelle carcasses, determine the range of marrow yields among individuals of different sexes and seasons of death, and compare the new data to gazelle skeletal element abundances from five Epipalaeolithic assemblages from Israel. We found extensive variation in marrow fat content among individual gazelles. Animals with the highest marrow yields were killed in the spring while animals killed in the early autumn had lower fat contents. Nevertheless, our results suggest that gazelle marrow provided a reliable, albeit small fat resource for prehistoric foragers in all seasons. Strong relationships between bone fragmentation and marrow content demonstrate that Epipalaeolithic people preferentially processed bones with high marrow yields.     

Identifying regional variability in Middle Stone Age bone technology: The case of Sibudu Cave

A few pieces of worked bone were previously reported from Sibudu, a site from KwaZulu-Natal in South Africa featuring a stratigraphic sequence with pre-Still Bay, Still Bay, Howiesons Poort, post-Howiesons Poort, late and final MSA cultural horizons. Here we describe an expanded collection of worked bones, including twenty-three pieces. Technological and use-wear analysis of these objects, and their comparison with experimental and ethnographic data, reveals that a number of specialised bone tool types (wedges, pièces esquillées, pressure flakers, smoothers, sequentially notched pieces), previously known only from the Upper Palaeolithic and more recent periods, were manufactured and used at least 30,000 years earlier at Sibudu Cave. These tools appear to be part of a local tradition because they are absent at contemporaneous or more recent southern African sites. Variability in Middle Stone Age material culture supports a scenario in which, beyond broad similarities in lithic technology, significant differences between regions, and trends of continuity at a local scale emerge in other aspects of the technical system, and in the symbolic domain. The archaeological record is revealing a complexity that prevents evaluation of the modern character of Middle Stone Age cultures in antinomic terms. We argue here that it is the detailed analysis of cultural variation that will inform us of the non-linear processes at work during this period, and contribute in the long run to explaining how and when crucial cultural innovations became established in human history.     

Baboon Bone Mineral Densities: Implications for the Taphonomy of Primate Skeletons in South African Cave Sites

C. K. Brain (e.g., 1981) documented an interesting difference in relative skeletal part representation between primates and bovids of similar live body size recovered from the fossil cave site of Swartkrans (South Africa). Hominids and baboons are represented primarily by skull parts and a paucity of postcranial bones, while small sized bovids (Size Classes 1 & 2) are represented by more equivalent abundances of all skeletal elements. Brain argued that the Swartkrans bones were primarily carnivore collected, and postulated that the difference in element frequencies between primates and bovids is the manifestation of less durable primate postcranial skeletons relative to those of bovids when either are subjected to a destructive process such as carnivore feeding. Experiments by Brain (1981) in which baboon and bovid carcasses were fed to large, African carnivores lend support to this hypothesis. Bovid postcranial elements survived carnivore feeding more frequently and more completely than those of primates. Assuming that bulk bone mineral density (bulk BMD) is a measure of durability, we supplement Brain's observational data by presenting the first systematic, element-by-element comparison of baboon and bovid postcranial bulk BMD measurements obtained by dual energy X-ray absorptiometry (DXA). While the bovid in our sample exhibits greater absolute bulk BMD values in 57·8% of all measured bone areas, when grouping areas by body region, a statistically significant difference in absolute bulk BMD values between the baboons and bovids is documented only in the hindlimb region (i.e., femur, tibia and patella). Density differences in other body regions are not statistically significant. Further, in only one case (i.e., small bovids in the Member 2 [1948–1953/1965–1975 excavation] assemblage) is there a significant and positive correlation between skeletal part frequencies of primates or bovids and bulk BMD. This suggests that, for the most part, primate and bovid skeletal part representation at Swartkrans is not the result of density-mediated processes. Differences in skeletal part representation between primates and bovids at Swartkrans may thus be attributable to factors other than bone density—such as bone size, length, shape, and/or the relative palatability of surrounding soft tissues on bones.     

Molluscan Shell Knives and Experimental Cut-Marks on Bones

Abstract

Experimentation demonstrates that the retouched edges of molluscan shells can be used effectively as butchery knives in the absence of lithic raw materials and leave striations on bone surfaces that may be indistinguishable from cut-marks made by stone knives. The potential of such non-lithic cutting tools suggests one new possible category of early artifact, and may explain the presence of cut-marks on fossil bones in paleoenvironments where stone artifacts were absent or rare.     

Spotted hyena (Crocuta crocuta) den use and taphonomy in the Masai Mara National Reserve,Kenya

Hyena taphonomy is of great importance to studies of hominid evolution, since these carnivore taxa have the highest potential both to produce large osseous assemblages and to modify existing hominid-accumulated assemblages throughout the Old World. The three extant hyena species (brown: Parahyaena brunnea; striped: Hyaena hyaena; and spotted: Crocuta crocuta) are all significant bone collectors and modifiers. Spotted hyenas generally have the lowest potential to accumulate osseous remains, and the rate of accumulation varies based upon the type of den. The present research examines the remains accumulated by spotted hyenas in Masai Mara Cave, Masai Mara National Reserve, Kenya. The contents of this den were collected twice by the authors, with an 11-year span interceding. The taphonomic signatures of spotted hyena interaction with bone are presented, including species and skeletal element representation, breakage patterns, tooth marks, tooth puncture, edge polish, and gastric corrosion. Other taphonomic factors examined include rodent gnawing and weathering stage. The cave den assemblage was accumulated at a rate of 30.4 identified specimens and a minimum of 4.1 prey individuals per year. In addition, the osseous remains accumulated by spotted hyenas at multiple burrow dens within the Reserve were examined for taxonomic representation and multiple taphonomic parameters. Rates of accumulation at this type of den tend to be very low, due to differential usage by spotted hyenas and the more ephemeral nature of earthen dens.     

A taphonomic study of bone modification and of tooth‐mark patterns on long limb bone portions by suids

This work presents new taphonomic data on bone modification by suids, including domestic pig, wild and hybrid boars. The intense modification undergone by bones from animals smaller than 100 kg is shown, together with a more moderate modification on bones from larger animals. Both the ravaging pattern (with preferential deletion of cancellous tissue) and the tooth‐marking frequencies are similar to those documented among hyenas and dogs when having primary access to complete bones. A dual‐patterned experimental model consisting of the interaction of humans and suids was also considered. Here it is shown how suid modification of hammerstone‐broken bone assemblages is different from that documented among canids and hyaenids, as experimentally replicated. These results increase the number of non‐anthropogenic bone‐modifying agents and posit new issues on equifinality processes. Copyright © 2008 John Wiley & Sons, Ltd.     

Vein quartz in lithic traditions: an analysis based on experimental archaeology

Worldwide, vein quartz was a commonly used raw material for stone tools but this material has proved difficult for archaeologists to analyse because many quartz assemblages appear to be comprised of amorphous pieces, not easily recognised as humanly modified or forming ‘tools’. This paper discusses the analysis of the debitage – focusing on the debitage fragmentation rate, the debitage, break, and fragment types, and the quantitative analysis of the complete flakes – resulting from experimental knapping of quartz, which formed part of a project which investigated the use of quartz in Irish prehistoric lithic traditions. The results have highlighted the complexity involved in analysing quartz assemblages, and the significant differences between the debitage products of quartz and chert knapping assemblages. While bipolar knapping is generally easy to differentiate from direct percussion, it is harder to differentiate between soft and hard hammer percussion.