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.     

Experimental examination of animal trampling effects on artifact movement in dry and water saturated substrates: a test case from South India

This paper presents the motivation, procedures, and results of an experiment that examines short episodes of animal trampling in dry and water saturated substrates in South India. While horizontal artifact displacement was similar to that modeled by other trampling experiments, vertical artifact displacement in water saturated substrates was greater than any reported experiment to date. The toolstone used in this experiment, a silicious limestone, exhibited minimal damage after trampling. Artifact inclination patterning appeared to be a potentially diagnostic middle-range marker of trampling in water saturated substrates. Given the abundant number of Paleolithic sites that are located on flat, open surfaces near water-bodies, or experience monsoonal climatic regimes, we propose that future excavations should measure artifact inclination on a regular basis.     

A new protocol to differentiate trampling marks from butchery cut marks

Microscopic signatures have previously been used to emphasize the similarities of butchery and trampling marks. The experimental background applied to differentiate both types of marks has been rather limited and authors have sometimes reached conflicting conclusions. This is partly due to methodological reasons: some authors have used very high magnification to examine microscopic features, whereas others have relied on more reduced magnification. Likewise, some experiments have exposed bones to trampling for reduced periods (minutes) whereas others have used longer time periods (hours). The present study stresses that the use of a scanning electronic microscope is not practical for identifying the impact of butchery and trampling marks in complete bone assemblages. It also emphasizes that previous studies have not addressed all the possible variables that could potentially be used to discriminate these marks, nor have they quantified the morphological patterns of each type of mark. Here we present a multivariate analysis of more than a dozen variables and show that butchery and trampling marks have very distinctive microscopic morphology. We advocate the use of a low magnification approach (≤40×), which can enable the analysis of complete assemblages using either hand lenses or binocular lenses. We also show the morphological criteria that differentiate butchery cut marks made with simple and retouched tools. We show that whereas complete discrimination of marks is impossible due to some degree of overlap, the list of criteria derived through multivariate analyses can be confidently used to correctly differentiate butchery and trampling marks in more than 90% of cases.     

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.     

A new element of trampling: an experimental application on the Level XII faunal record of Bolomor Cave (Valencia,Spain)

In Level XII of Bolomor Cave (Valencia, Spain) modifications have been observed on some of the bone fragments that make up the faunal record. These alterations consist of small notches located on the oblique fracture angles of some bones. The frequency at which these modifications appear in the assemblage has obliged to plan several experimental series to know the process that causes them. To be more exact, this study aims to verify whether these small chips are the result of trampling. For this purpose, two experimental series have been developed. The first of which has the objective of differentiating between the variables related to the original state of the bone (green, semi-dry and dry) and the second is aimed at reproducing the modifications observed in the archaeological set, taking into account the data obtained in the previous series. Following these experiments, the appearance of small notches is observed on the oblique fracture angles of some bones in semi-dry state. These resulting chips are similar to those documented in Bolomor Cave, Level XII. Therefore, it is deduced that trampling is the principle cause of these modifications in the bone record. This fact has important archaeological implications, as the spatial distribution of this modification can provide information about the intrasite movements of the human groups.     

Assessing the macrofracture method for identifying Stone Age hunting weaponry

Macrofracture analysis is an experimentally derived method used as an initial step in investigating the hunting function of stone artefacts. Diagnostic impact fractures, which can only develop as a result of longitudinal impact, underpin this method. Macrofracture analysis recently gained favour in Middle Stone Age studies, supporting hypotheses for effective hunting during the late Pleistocene in southern Africa. However, the factors affecting diagnostic impact fracture formation and the interpretation of these fracture frequencies are not yet fully understood. This paper outlines a set of experiments designed to test macrofracture formation under human and cattle trampling and knapping conditions. The results show that: (a) macrofractures occur frequently when stone artefacts are trampled by cattle and humans and in knapping debris; (b) diagnostic impact fractures occur on some of the trampled flakes and knapping debris (≤3%), but significantly less often than in previous hunting experiments; (c) when they do occur, they are likely produced by longitudinal forces similar to those experienced during hunting; (d) considering artefact morphology is important during macrofracture analysis; and (e) macrofracture analysis is not a standalone method, but is most useful as part of a multi-analytical approach to functional analysis. These experiments help to establish a significant baseline diagnostic impact fracture frequency for the interpretation of archaeological macrofracture frequencies.