Actualistic research into dynamic impact and its implications for understanding differential bone fragmentation and survivorship

The relationship between bone mineral density and archaeological bone survivorship has played a critical role in zooarchaeological and taphonomic studies in recent decades. Numerous studies have suggested that higher-density skeletal element portions survive more frequently than lower-density element portions when archaeological assemblages are affected by some taphonomic processes. Interpretations of density mediated destruction have become commonplace in the archaeological literature, and are often used to explain the absence of certain bone elements and element parts in zooarchaeological assemblages. This study explores the effects of rockfall on bovid elements in varied environmental conditions and the differential survivorship of their element parts, and has implications for understanding the taphonomic processes through which bones are subjected to dynamic loading. Actualistic rockfall experiments conducted on twelve samples of frozen, fresh, and semi-dried bovid bones reveal that the generally low-density epiphyseal ends of bone elements resist fracture and analytical deletion with more frequency than the higher-density diaphyses. This evidence suggests that bone density does not correlate with likelihood of breakage or effective archaeological “destruction” when rockfall and other processes that result in dynamic impact are in action. While this research does not question the relationship between bone mineral density and the likelihood for archaeological survivorship as the result of some taphonomic processes, it presents one specific set of taphonomic processes that result in the differential survivorship of low density bone elements parts and the fragmentation and destruction of higher density element parts. This research presents evidence that shows that dynamic impact is a process capable of fragmenting and sometimes destroying high-density elements while low-density elements survive.     

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.     

Gazelle bone fat processing in the Levantine Epipalaeolithic

We investigate mountain gazelle (Gazella gazella) carcass processing to reconstruct resource intensification strategies during the Epipalaeolithic period of northern Israel. We adopt a multivariate taphonomic approach to identify the processes that most influenced bone survivorship in five gazelle assemblages. All of the assemblages are characterized by significant density-mediated biases, yet in situ attrition played a minimal role in assemblage formation. In contrast, the survivorship of hare (Lepus capensis) skeletons is not mediated by bone density indicating that different prey taxa experienced independent taphonomic histories. Both gazelle cortical and cancellous bone is highly fragmented and the degree of fragmentation and survivorship are strongly correlated with fat yields. Results of multiple tests point to intensive marrow and grease extraction as the primary determinant of gazelle bone survivorship. Although gazelle carcasses were intensively utilized throughout the Epipalaeolithic, the intensity of use is stable across the duration of the period.     

The recovery and interpretation of microvertebrate bone assemblages from archaeological contexts

The analysis of microvertebrate remains recovered from buried contexts is frequently problematic for archaeologists. Diminutive size is a major obstacle to recovering, identifying, and interpreting microfaunal bone materials successfully. Their taphonomic history is often obscure, thus the significance of microvertebrate accumulations for settlement, subsistence, and ecological interpretation is difficult to evaluate. Recognizable and reliable archaeological signatures are sought for assessing the effect of taphonomic history on microvertebrate assemblages. Relevant signatures of bone damage, skeletal survivorship, taxonomic composition, and context are examined in assemblages produced and modified through accidental non-predator-related death, predator accumulation, and postmortem alteration.     

Food for thought: using game cameras to better understand the movement of bones by scavenging in archaeological faunal assemblages

This paper questions our understanding of the movement of bones by animal scavengers in the archaeological record. Since assumptions regarding the effects of animal scavenging shape final interpretations of skeletal element frequencies in archaeological faunal assemblages, they are important for our understanding and reconstruction of ancient human behaviour. The results of a 4-year actualistic kangaroo scavenging study from Australia are used to question our understanding of the movement of the bone by contrasting visual data captured by motion-activated digital game cameras with traditional taphonomic studies using skeletal element frequencies. Game cameras are commonly used by ecologists to capture the behaviour of living species but have not yet been used in experimental archaeology where visually documenting animal scavenging behaviour can be used to understand the movement of carcasses and individual bones. Results suggest that traditional zooarchaeological analyses may not be accurate indicators of hunted versus scavenged prey in archaeological faunal assemblages. Moreover, they most certainly fail to document the entire suite of animals scavenging a carcass. These implications are discussed with particular reference to the ability to definitively ascertain the role of humans in the megafaunal extinction debate in Australia.     

Site formation processes in relation to surface bone assemblages in the Fuegian steppe (Tierra del Fuego,Argentina)

The archaeological record of the northern steppe in Tierra del Fuego (Argentina) is characterized by the occurrence of concentrations of archaeological material at the ground surface, coming from gullies and deflation hollows related to shallow lake coastal environments. This particular distribution becomes a challenge concerning the study of site formation processes, particularly in relation to the burial and exhumation of archaeological materials. Bone assemblages coming from three archaeological contexts (Tres Marías, Amalia 4 and Arturo 1) are analysed here, pointing to the features, damage and stability or movements that reveal their taphonomic histories. Geomorphological landscapes vary from each site, being represented by deflation hollows close to shallow lakes as well as gullies originating from the coast itself. The faunal assemblages are mostly dominated by Lama guanicoe bones. Variability in taxonomic composition, weathering profiles, mobility and stability of materials, as well as evidence of anthropic modifications, among other records, demonstrate the existence of different depositional events. The high variability observed suggests that several pre- and post-depositional processes were involved; thus, it results in complex taphonomic histories and low integrity that make their interpretation difficult in terms of human activities.     

Intrataxonomic variability in metapodial and femur bone density related to age in guanaco (Lama guanicoe). Zooarchaeological and taphonomical implications

The aim of this paper is to present new information about bone mineral density (BMD) variability in guanaco (Lama guanicoe), a South American wild camelid; while taking into account its ontogenic development. The importance of considering intrataxonomic variability in bone density related to age for constructing zooarchaeological indices and applying them to archaeological assemblages is also discussed. The results presented here were developed from a large sample of 46 metacarpals and 45 femurs of modern guanacos, ranging in age from ca. 6 months of gestation to 12 years. Bone structural densities were measured using a biphotonic X-ray densitometer, DEXA method, Norland EXCELL and the bone mineral content (BMC) of each scanned portion or complete element was divided by its volume, which was obtained independently by water displacement. Our results indicate that the bone density of each anatomical unit is highly variable, even among individuals of the same species. According to metacarpals data, age is an important factor affecting BMD. Moreover, our study shows that the density ranges of different skeletal elements can overlap, suggesting that it is not possible to predict that a certain element is always denser than another one. Finally, we present new evidence about the potential age-related taphonomic bias in faunal assemblages, indicating that meanwhile some skeletal elements show clear differences in their density between their fused and unfused state (metacarpal) other do not (femur).     

Probable evidences of bone accumulation by Pleistocene bearded vulture at the archaeological site of El Mirón Cave (Spain)

The bearded vulture (Gypaetus barbatus), a bird or prey that mainly feeds on bones of large mammal carcasses, has been recently evidenced as an accumulating agent with significant contributions to palaeontological assemblages in caves and shelters, but extremely rare at archaeological sites. The results of the taphonomic analyses carried out in the Upper Palaeolithic layers of El Mirón Cave (Cantabrian Spain), which are presented here, evidence the existence of special digestive marks and a typical skeletal pattern in a noticeable amount of small and medium-sized ungulates bones. This fact suggest that a representative part of the bone assemblage has been caused by bearded vultures, and strengthens the idea that this bird has to be definitely included among other potential non-human accumulators in archaeological sites.     

The Use of Multiple Correspondence Analysis (MCA) in Taphonomy: The Case of Middle Helladic Asine,Greece

The goal of this paper is to investigate whether multiple correspondence analysis (MCA), a multivariate statistical technique, is a useful dimensionality‐reduction tool in zooarchaeological and taphonomic studies. For this purpose, the focus is to detect and discuss traces of waste management. Animal bones from waste‐related contexts at the Bronze Age site Asine, Greece, are investigated. The data consist of bone fragments dating to the Middle Helladic from this site. Unidentified fragments were categorised in size classes, where possible. Information on taxa, skeletal parts and the presence or absence of several taphonomic markers is included in the data set. The MCA reveals several correlations of zooarchaeological interest. For example, the association between indeterminate fragments and calcined bone points to issues concerning identification and preservation. Floors are characterised by weathered long‐bone fragments from medium‐sized mammals. Additionally, the results of MCA indicate that the material might have suffered from density‐mediated attrition, based on the abundance of axial fragments, which did not differ between different contexts and taxa. The results show that MCA can be used to detect zooarchaeological and taphonomic patterns. This multivariate technique is useful when investigating large data sets, as is often the case with large zooarchaeological assemblages. Copyright © 2016 John Wiley & Sons, Ltd.     

A New Approach to Identifying Bone Marrow and Grease Exploitation: Why the “Indeterminate” Fragments should not be Ignored

The economic importance of bone fat to past peoples is discussed and the ethnography of bone marrow and grease extraction is briefly outlined. Models for expected patterns of bone fracture and fragmentation, relating to the exploitation of bone marrow and grease, are described. Current methods for assessing bone fracture and fragmentation, in archaeological assemblages, are discussed and a new methodology is suggested. The importance of retaining and studying the “indeterminate” class of fragments is stressed. The new methodology employs a fracture freshness index (FFI) to study fracture type, and fragmentation is assessed through the separation of fragments into size classes and different bone types. An example application is given.     

Comparing Levels of Subsistence Stress amongst Norse Settlers in Iceland and Greenland using Levels of Bone Fat Exploitation as an Indicator

Abstract

The background to the Icelandic and Greenlandic sites under investigation is outlined and prior work on the Norse economies of the two islands is discussed. The importance of fat in the diet and the use of levels of bone marrow and grease exploitation as an indicator of subsistence stress are explained. The methodology for establishing levels of bone fat exploitation is outlined. This methodology involves the detailed study of fragmentation levels of different types of bone, study of bone fracture types and many other taphonomic indicators. The results of the study are described and discussed. On Greenland, the Norse inhabitants exploited almost all available fat from land mammal bones, leaving only the ribs. It is argued that this indicates a severe level of subsistence stress amongst the Greenlanders that is most likely related to a seasonal dearth in resources. On Iceland, whilst a certain amount of bone marrow is almost certainly exploited, the settlers appear to almost totally ignore the potential to exploit bone grease. This is likely to be indicative of a much more healthy subsistence economy than on Greenland. These results are discussed in relation to differing climate, availability of good soil, fishing practices and seasonal rounds.     

Taphonomic analysis of rodent bone accumulations produced by Geoffroy's cat (Leopardus geoffroyi, Carnivora,Felidae) in Central Argentina

Rodent prey remains recovered from Geoffroy's cat (Leopardus geoffroyi) scats were analyzed in order to identify taphonomic features produced by this predator. The analysis includes a year-long sampling discriminated by the seasons. Modifications produced by digestion are heavy. Taphonomic variables in samples discriminated by the seasons did not show major differences with respect to the total sample; thus, scats collected in any season clearly show the modifications on the bones of prey rodents made by Geoffroy's cats. The results presented here and its interpretation could be extrapolated to an analysis of zooarchaeological or paleontological assemblages.     

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.     

Túnel: A Case Study of Avian Zooarchaeology and Taphonomy

Although not often considered, there are many osteological characters unique to the avian skeleton that influence the taphonomy of bird bones. These characters are reviewed and their archaeological significance discussed herein. The presence of marrow in many avian long bones is important to interpretation of avian remains from archaeological sites because the presence of marrow affects bone density and, in turn, preservation. Other structural properties that affect avian bone preservation include cortical wall thickness, length and pneumatic state. Based on an analysis of approximately 10,000 bird bones from the archaeological site of Túnel, Tierra del Fuego, Argentina, I found that specific breakage patterns resulted from natural taphonomic processes acting as a result of the unique avian bone characteristics. This information may allow researchers to distinguish breakage patterns in avian bones resulting from natural taphonomic processes from breakage patterns that are culturally induced.     

Zooarchaeology and Historical Archaeology: Progress and Prospects

This review assesses the development and current status of zooarchaeological research in historical archaeology. Analytical issues in recovery, identification, quantification and interpretation are discussed with particular reference to assemblages from historical sites. The results section summarizes the substantive contributions zooarchaeological studies of historical assemblages have made to our understanding of past diet, food production systems, social and cultural variation, and archaeological interpretations. The last four decades of research has provided a strong basis for future analyses that draw together diverse strands of zooarchaeological, historical, scientific, and anthropological evidence.     

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.     

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.     

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.     

Taphonomic analysis of remains of mammals eaten by pumas (Puma concolor Carnivora, Felidae) in central Argentina

Prey remains recovered from puma (Puma concolor) scat were analyzed in order to identify taphonomic features produced on them by this predator. Mammal remains are abundant in puma scat, but recognition of bone remains decreases as prey size increases. Modifications produced by digestion are strong. However, micromammal bones show a gradation in preservation that includes well preserved specimens. Data presented here and their interpretation may possibly be extrapolated to zooarchaeological or paleontological assemblage.