Biosphere to Lithosphere: new studies in vertebrate taphonomy

By Terry O'Connor

Taphonomic studies are a major methodological advance, the effects of which have been felt throughout archaeology. Zooarchaeologists and archaeobotanists were the first to realise how vital it was to study the entire process of how food enters the archaeological record, and taphonomy brought to a close the era when the study of animal bones and plant remains from archaeological sites were regarded mainly as environmental indicators. This volume is indicative of recent developments in taphonomic studies: hugely diverse research areas are being explored, many of which would have been totally unforeseeable only a quarter of a century ago.

• Language: English
• Publisher: Oxbow Books
• Release date: Sep 12, 2016
• ISBN: 9781782979173

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Preface

Peter Rowley-Conwy, Umberto Albarella and Keith Dobney

This book is one of several volumes which form the published proceedings of the 9th meeting of the International Council of Archaeozoology (ICAZ), which was held in Durham (UK) 23rd–28th August 2002. ICAZ was founded in the early ’70s and has ever since acted as the main international organisation for the study of animal remains from archaeological sites. The main international conferences are held every four years, and the Durham meeting – the largest ever – follows those in Hungary, the Netherlands, Poland, England (London), France, USA, Germany and Canada. The next meeting will be held in Mexico in 2006. The Durham conference – which was attended by about 500 delegates from 46 countries – was organised in 23 thematic sessions, which attracted, in addition to zooarchaeologists, scholars from related disciplines such as palaeoanthropology, archaeobotany, bone chemistry, genetics, mainstream archaeology etc.

The publication structure reflects that of the conference, each volume dealing with a different topic, be it methodological, ecological, palaeoeconomic, sociological, historical or anthropological (or a combination of these). This organisation by theme rather than by chronology or region, was chosen for two main reasons. The first is that we wanted to take the opportunity presented by such a large gathering of researchers from across the world to encourage international communication, and we thought that this could more easily be achieved through themes with world-wide relevance. The second is that we thought that, by tackling broad questions, zooarchaeologists would be more inclined to take a holistic approach and integrate their information with other sources of evidence. This also had the potential of attracting other specialists who shared an interest in that particular topic. We believe that our choice turned out to be correct for the conference, and helped substantially towards its success. For the publication there is the added benefit of having a series of volumes that will be of interest far beyond the restricted circle of specialists on faunal remains. Readers from many different backgrounds, ranging from history to zoology, will certainly be interested in many of the fourteen volumes that will be published.

Due to the large number of sessions it would have been impractical to publish each as a separate volume, so some that had a common theme have been combined. Far from losing their main thematic focus, these volumes have the potential to attract a particularly wide and diverse readership. Because of these combinations (and because two other sessions will be published outside this series) it was therefore possible to reduce the original 24 sessions to 14 volumes. Publication of such a series is a remarkable undertaking, and we are very grateful to David Brown and Oxbow Books for agreeing to produce the volumes.

We would also like to take this opportunity to thank the University of Durham and the ICAZ Executive Committee for their support during the preparation of the conference, and all session organisers – now book editors – for all their hard work. Some of the conference administrative costs were covered by a generous grant provided by the British Academy. Further financial help came from the following sources: English Heritage, Rijksdienst voor het Oudheidkundig Bodemonderzoek (ROB), County Durham Development Office, University College Durham, Palaeoecology Research Services, Northern Archaeological Associates, Archaeological Services University of Durham (ASUD), and NYS Corporate Travel. Finally we are extremely grateful for the continued support of the Wellcome Trust and Arts and Humanities Research Board (AHRB) who, through their provision of Research Fellowships for Keith Dobney and Umberto Albarella, enabled us to undertake such a challenge.

It was particularly pleasing to have a strong session on taphonomy at the conference. Taphonomic studies are a major methodological advance, the effects of which have been felt throughout archaeology – and zooarchaeology can be justly proud to have been a co-originator of the entire field of study, along with our sister discipline archaeobotany. Archaeological food remains – of both animal and vegetable origin – have all reached us via a long process of procurement, preparation, consumption and discard – to say nothing of the post-depositional factors affecting these quintessentially organic materials.

It was perhaps inevitable that zooarchaeology and archaeobotany were the subdisciplines that first realised how vital it was to study the entire process, and in so doing made taphonomic studies uniquely archaeological. They became archaeological by focussing on the human behaviours that gave rise to the archaeological record. Taphonomy brought to a close the era when the study of animal bones and plant remains from archaeological sites were regarded mainly as environmental indicators. No longer were taphonomic factors seen as distorting the nature of the sample; they became instead the very object of enquiry, revealing a great deal about both human behaviour and about natural conditions on the site.

Taphonomy was therefore an inevitable choice when we were looking for themes for the ICAZ conference. We were delighted when Terry O’Connor picked up the theme, and this volume is the outcome of his efforts. As Terry notes in his introduction, the importance of the topic is such that he could have filled far more than the time available at the ICAZ conference. This volume is indicative of recent developments in taphonomic studies: hugely diverse research areas are being explored, many of which would have been totally unforeseeable only a quarter of a century ago. And if Efremov, the inventor more than 60 years ago of the term taphonomy, could read this book, he would surely be amazed.

Biosphere to Lithosphere: an introduction

Terry O’Connor

"The chief problem of this branch of science is the study of the transition (in all its details) of animal remains from the biosphere into the lithosphere, i.e., the study of a process in the upshot of which the organisms pass out of the different parts of the biosphere and, being fossilized, become part of the lithosphere" (Efremov 1940, 85).

Perhaps it is too obvious to introduce a volume of papers on vertebrate taphonomy with Efremov’s much-quoted definition of what we are about. The formation (in all its details) of the zooarchaeological record has certainly developed its own research agenda since Efremov’s day, and much of his essentially palaeontological study of the subject seems peripheral to our investigations of vertebrate assemblages from comparatively recent times. None the less, our aims are much the same – to study and understand the processes that have interceded between the sample of dead bones on the bench and the living community from which they originate, and about which we hope to learn something. The Taphonomy session at the 2002 ICAZ Conference could easily have filled more than its allotted day, such was the enthusiasm to report and discuss investigations into the deposition, destruction, and recovery of vertebrates. The papers in this volume originate from that session, and reflect its stimulating and eclectic character.

The papers can be loosely grouped into three categories. Some derive evidence from modern field observations to apply by analogy to the interpretation of archaeological evidence. Others report mostly experiment -based investigations of specific causative factors in bone degradation, whilst the third group consists of archaeological investigations in which taphonomic aspects are a major part of the study. One of the satisfying aspects of studying taphonomy is the lack of chronological or regional constraints. The papers presented here encompass the Lower Pleistocene to the recent past, and range from the Arctic to South America, Europe, and the Middle East. Of the materials that are the object of study, bones not surprisingly predominate. That remarkable composite biomaterial is one of the most resistant of zooarchaeological fossils, enduring putrefaction, fragmentation, and burning, not to mention archaeological recovery, to be one of the most abundant and widespread of archaeological ‘finds’. Animals leave other traces, however, and it has been a pleasure to be able to include here papers on the fossil traces of animal faeces, and on the survival in bone of DNA and other large biomolecules. So extensive is the potential evidence of past animals (skin, hair, horn, feathers, organs, eggshell, tracks), and so diverse the taphonomic pathways of those different forms of evidence, that any single volume cannot encompass the whole field. It may appear a little churlish for the Introduction of such a volume to turn to a discussion of topics that vertebrate taphonomy seems to be neglecting, but only through such discussion do we avoid the intellectual fossilisation that comes with complacency.

To run through the taphonomic trajectory from the top, the biotic attributes of life assemblages are often the aim of our research. The vertebrates whose remains we study were brought together, deliberately or inadvertently, by human activity, or by environmental factors that also affected humans or hominins. Those past people and their environment are the object of our study, though, as Jim Williams reminds us in this volume, our modelling of the population and community processes that modify the original life assemblage of other species is not always sufficiently detailed and informed by current neoecological research. Death intervenes, and our research turns to the biostratinomic processes that lead to death assemblage formation, processes that are quite well represented here.

What is less well represented in the literature is sufficient consideration of the event that separates life from death assemblages, namely death. More often than not, the cause of death of vertebrates in zooarchaeological assemblages is that they have been killed by the people whose archaeological record we are investigating. However, most assemblages include remains of animals for which that was not the case. Some may be the prey of companion animals or commensals that lived around the human settlement, and some will be animals that simply happen to have died within the biostratinomic catchment of the deposits that we are investigating. In the first case, recognising that prey component, and correctly attributing the cause of death, adds a little more detail to our understanding of the small-scale ecology of the settlement. One of the many excellent posters that enlivened the ICAZ Conference demonstrated the use of small mustelids as a means of pest control at Pompeii. That intriguing and unexpected aspect of life in Roman Italy’s most iconic town only came to light because rodent bones were examined with particular care to establish the cause of death. In the second case, we have to accept that death occasionally comes to vertebrates in stochastic ways and unpredictable places, and not become too concerned to explain away every single record of species encountered as fossils where we do not expect them to have been.

To develop that point, consider the metaphor of Alkan’s Bookcase. On or about the 29th of March, 1888, the brilliant French pianist and composer Charles-Valentin Alkan was found dead. Accounts vary somewhat, but essentially his body was found beneath a large bookcase, from a high shelf of which he was removing a book when the bookcase fell on him. As causes of death go, Alkan’s demise was random and unpredictable. It reminds us that odd things happen, that those odd things sometimes generate death assemblages, and that we are not going to be able to fit everything that we encounter in the zooarchaeological record into a normative model. That might seem to contradict the proposal that we should pay closer attention to causes of death. However, if we consider the case more closely, there is a useful lesson to transfer into vertebrate zooarchaeology. Alkan was studious, reclusive, and elderly. He was therefore far more likely than most 19th century French people to be engaged with heavy bookcases; less likely to be able to avoid a toppling bookcase; and not in a position to call for immediate help. In short, although death by bookcase may be exceptional, Alkan was inherently more likely to suffer it than most.

To extend that point to other animals, the University of York reference collections include a common scoter Melanitta nigra that was acquired in unusual circumstances. Scoters are pelagic ducks, their remains usually collected as partly-decayed tideline corpses, as the birds rarely venture inshore. This particular scoter died some tens of kilometres inland, having been hit by a bus. At first glance, this is another random, inexplicable death. However, on dissection, it was evident that the scoter was markedly under-nourished, with little body fat and some signs of muscle wasting. It was a long way from the sea, starving, and its ability to recognise and avoid a potentially dangerous situation must have been impaired. Furthermore, the cause of death would have been completely unfamiliar. To inland birds, road traffic is a familiar hazard: corvids scavenging road-kill are quite adept at hopping aside at the last moment as a vehicle goes past. The scoter was inherently more likely to die where it was found, simply because it was out of its normal life-range and therefore unable to feed, and it was maladapted to the potential dangers. Human settlement and other activities create patches of altered environment within which the probability that death will occur must be significantly raised for species other than those, such as commensal species, that are behaviourally adapted. Different individuals within a population will be more or less likely to survive in that altered environment, depending on individual attributes of age, sex, health, breeding condition, and so on, but the enhanced probability of death is likely to affect all of them to some degree.

For a vertebrate taphonomist, then, there is an interesting challenge. On the one hand, we have to accept that stochastic terminal events result in the presence in our assemblages of specimens that defy a normative interpretation. On the other hand, if we go beyond asking ‘Why are these bones in this deposit?’ to ask ‘What killed this animal?’, we may extend and deepen our understanding of the diverse interactions that went on in the past, and we may, too, glean some insights from even the most apparently arbitrary of death assemblages.

From death we move to deposition, and to the formation of the fossil assemblage and its diagenetic modification. The last few years have seen significant advances in our understanding of the diagenesis of bone, based in part on empirical data from ancient bones in a range of states of preservation, and in part on data from laboratory studies. Although there is much more to learn, we have at least the outlines of an understanding of how buried bone reacts with the sediment around it. What might now engage our attention rather more is the reaction of the sediment to the bone fragments buried in it. In at least some archaeological deposits, bone is an abundant clast, a significant component of the sediment. Bone fragment size affects the particle size distribution of the sediment and thus its capacity to drain or hold water, and hence its oxic or anoxic condition. More subtly, the presence in a sediment of bone undergoing gradual demineralisation or hydrolysis of collagen must affect the chemistry of the sediment matrix, and the bone may also affect the sediment biota if it serves as a pabulum for microbial populations. As zooarchaeologists, we are accustomed to concentrate on the bones, and the effect that the sediment matrix and ground water may have had on bone diagenesis. It may be instructive to turn that investigation around, to understand more fully what effect degrading bone has on the sediment matrix, and therefore on other materials contained within it.

Among the last steps in the taphonomic trajectory are the processes of archaeological sampling and recovery. It could be argued that issues of sampling strategy and sieving (screening) procedures do not constitute taphonomy in the Efremov sense, as they affect the transition of the organism from the lithosphere to the realms of data and knowledge (the noosphere?). No papers on sampling or recovery methods were offered for this session. Perhaps that reflects the influence of Efremov’s definition of taphonomy, or perhaps so many papers on the subject were published in the 1970s and 1980s that the topic is now regarded as thoroughly worked-out, to be left like some abandoned mine until it becomes the subject of historical curiosity! However, our zooarchaeological investigations still stand or fall by the quality and consistency of our data recovery. The premise that sieving of sediments is essential for satisfactory bone recovery was established in the 1970s, yet it is still not standard practice on all excavations. Why is that: have we been talking to each other more than to field archaeologists?

Ultimately, a deeper understanding of the taphonomy of vertebrate remains can enhance our interpretation of a site, or of a region, or of a class of monument. The last few papers in this volume cover the range of taphonomic interpretation, from a large-scale regional study (Marzinano and Chilardi), through site-specific formation processes (Belmaker; Bar-Oz et al.), to investigation of specific human behaviours (Phoca-Cosmetatou, Marciniak). This diversity makes the point that vertebrate taphonomy is highly interdisciplinary. It has aspects that are essentially palaeontology, based on principles of biostratinomy that would apply equally to Quaternary proboscideans or to Permian therapsids. Another aspect is applied chemistry, exemplified here by Geigl’s review of the diagenesis of DNA and related biomolecules. This is an area of research that has advanced rapidly in recent years, as developments in analytical hardware have made it possible to address ever more specific questions. Biomolecular archaeology is becoming a major research area in its own right, and we may need to take care to ensure that the analytical developments do not become an end in themselves. Finally, of course, vertebrate taphonomy has an archaeological aspect. Helping us to elucidate the human past through a more detailed understanding of the taphonomic consequences of collective and individual acts. We may view those acts with an anthropological eye, as Marciniak does in the last paper here, or we may see those human activities as the sociallycomplex equivalent of the arctic foxes that feature in Pasda’s contribution, or the raptorial birds whose feeding behaviours Bochenski and Larouladie have meticulously demonstrated, or the owls invoked by Williams and, inter alia, by Belmaker. Those paradigms are not contesting or mutually exclusive, and the message that comes most clearly from this collection of papers is that there is no ‘right way’ to pursue vertebrate taphonomy.

The death, decay, and deposition of vertebrates is a fascinating subject, and a rich vein for research. The papers presented here show something of the diversity and maturity of that research, and reflect the ‘buzz’ of a particularly satisfactory conference session. On a personal note, I would thank the many colleagues from throughout the world who, whatever their first language, have written their contributions to this volume in (often excellent) English. In editing those papers, I have sometimes corrected or clarified the English, but have tried to keep such changes to the essential minimum so that the individual styles of the different authors remain apparent to the reader. All of the contributors have been patient and supportive of that process, and I thank them all.

Finally, I am grateful to the 2002 ICAZ Conference organisers, Umberto Albarella, Keith Dobney, and Peter Rowley-Conwy for making it possible for us to hold the Taphonomy session; to the funding agencies that made it possible for some of the contributors to attend the Conference; to various colleagues who have refereed the papers; and to Liz King at Oxbow Books for seeing this volume through to publication.

1. Some taphonomic investigations on reindeer (Rangifer tarandus groenlandicus) in West Greenland

Kerstin Pasda

In 1999 and 2000 an archaeological survey took place in the southeastern part of the Sisimiut-district in West Greenland (Fig.1.1: area 1 and 2). Research by wildlife biologists on reindeer in this region had been carried out recently (e.g. Thing 1984). Archaeological, ethnohistorical (Grønnow et al.1983) and archaeozoological (Meldgaard 1986) investigations supplement the picture. In this inland tundra with a mainly continental climate (Bøcher et al. 1980, 26, 44), the vegetation growth and cover is quite strong (Grønnow 1986, 67). Numerous remains of reindeer that died mostly of natural causes can be found in different stages of skeletal decay (e.g. Beyens 2000, 61; Vibe 1967, Fig.92, 93). The condition of the carcasses ranges from relatively fresh (still covered with skin and sinew) to completely defleshed and disarticulated skeletons, and isolated bones.

Throughout the survey 154 reindeer cadavers and about 670 single bones have been examined. For the determination of the biological age the methods of Hufthammer (1995) and Miller (1976) have been used. For sex determination, the shape and thickness of the ventro-medial wall of the acetabulum have been used visually; as in other artiodactyls, this part of the pelvis has diagnostic value (Boessneck et al. 1964, 89; Lemppenau 1964, 20). Various taphonomic aspects of those skeletons found in the tundra were examined:

a. their demography was compared to that of the living population,

b. the decomposition of reindeer cadavers in an arctic tundra,

c. the representation of skeletal parts in different locations (e.g. fox dens) and their comparison with archaeological sites,

d. carnivore gnawings and the pattern of bone fracturing.

The result of the examinations of reindeer skeletons in a recent arctic landscape contribute to the understanding of the development of bone accumulation in archaeological sites.

Demographic investigations

Thing (1984, 9–10; 1980a; 1980b, 151) describes today’s distribution of reindeer in their winter and summer habitat and their migration routes (Fig.1.1). Outside these areas reindeer are rare but present all year round. The major calving area (Fig.1.1: area 2) lies within the summer range. The summer range (Fig.1.1: S1) is occupied mainly from the first half of May until the first half of September. At the beginning of winter reindeer migrate usually within two or three weeks c. 50 – 70 km into their main winter habitat (Fig.1.1: W1). Little is known about the second summer habitat (Fig.1.1: S2) south of Kangerlussuaq. It is likely that in times of maximum population reindeer live here all year round. Only a part of them migrates into the main winter habitat (Meldgaard 1986, 21). A few animals migrate from the main summer habitat S1 into the second winter habitat W2 near the icecap.

Altogether, the sex and age of 154 complete carcasses, skeletons, and skeletal parts could be determined (Table 1.1). The spatial distribution of these carcasses show that the thanatocoenose in the examined area is a reflection of the seasonal activities of the living population: among the 79 subadult and adult carcasses 68% were females. The dominance of female skeletons is not surprising, as in living populations adult females usually predominate (e.g. Bergerud 1980, 565–566; Skogland 1985). The sex proportion is based on the different mortality of males and females. This begins at 3–4 years and increases with age to the disadvantage of the males. This sex proportion can also be seen in Pleistocene bone assemblages in Europe (Weinstock 2000, 57–58). Adult females die mostly around calving time or during lactation in late winter or early spring (Ringberg et al. 1980, 333–340; Thing and Clausen 1980, 434; Weinstock 2000, 57). This can be seen in the area under study (Table 1.1): All dead adult animals (n=22) within the radius of about 10 km around the calving area (Fig.1.1: area 2) are females. This confirms observations of spatial distribution of the living population (Thing 1984, 9). A seasonal determination of reindeer carcasses through the size and morphology of antlers was not possible, because nearly 60% of the females of this region are antlerless (Meldgaard 1986, 52–3). Remnants of skin on the carcases – consisting mainly of very long white hairs – suggests that death occured during winter. Those adult females that died in area 2 were probably weakened by pregnancy and birth. They probably died just before or after calving. The old age of most of the female carcasses – which can be inferred by the advanced wear of their teeth – may have contributed to this.

Figure 1.1: Central West Greenland (Sisimiut- and Maniitsoq-district), winter (W1, W2) and summer range (S1, S2) and migration routes (arrows) of reindeer (after Thing 1984, fig.3). Area 1: examined area in 1999 and 2000. Area 2: calving area in S1 as observed by wildlife biologists.

Comparatively many (29 of 54 or 54%) of the newborn calves and the few-weeks-old animals were found within and around the calving area (area 2; Table 1.1). In one case the remnants of a foetus were found in the abdomen of a rather old female. The percentage of very young animals in area 1 is at 33% comparatively low. The percentage of adolescent animals here, however, is, at 10%, higher than in area 2. Thing and Clausen (1980, 434) report that in the examined area in 1977 the death rate of 2–3-month-old calves was 50%. This high percentage results from calves’ illnesses such as infections, infestation of parasites or diarrhoea. These were often caused by the bad general condition of the mothers during pregnancy which led to the weakening and the susceptibility of the young animals (e.g. Espmark 1980, 495). Miller and Broughton (1974) documented in Canada that a huge percentage of the calves died because of bad weather conditions or because of being deserted by their mothers (see Skogland 1989, 55). Foxes and ravens are supposed to play an important role in the newborn reindeers’ deaths in Canada (Nowosad 1975, 207).

Decomposition of carcasses

In the examined area twelve reindeer carcasses were drawn on a scale of 1:20 (e.g. see Fig. 1.2). A further skeleton was documented by photographs. Their geographical position was determined by GPS. Skeletons of different stages of decomposition and skeletal decay and of different ages were chosen for the documentation. They ranged from complete skeletons with sinews and remnants of skin to totally defleshed bones. All reindeer died a natural death. No typical location could be detected where remnants of reindeer lay: they were found on the banks of lakes, in the water, in valleys, on hills, under cliffs or on slopes. Big antlers, which rose above the low vegetation, could be spotted most easily. Sometimes skeletons could be seen through binoculars from elevated locations.

Table 1.1: Age and sex of documented reindeer carcasses in the study region.

area 1: summer range S1 and migration route to W1 (Fig. 1.1)

area 2: calving area in S1 (Fig. 1.1)

Figure 1.2: Nearly complete reindeer carcass with feather of a raven (R) between ribs and remains of hair (grey: boulder).

Four of the skeletons that had been drawn or photographed in the year 1999 had been revisited in the following year to observe their decomposition. Surprisingly, it turned out that their situation had changed very little after 12 months (Figs 1.3 and 1.4). The position of their bones and their disarticulation had progressed very little. The skin, sinews and maggots that had been observed the year before, were still present. However, Fig. 1.4 shows that the amount of skin was reduced compared with the year before (Fig. 1.3). The skin cover of the skull had decreased. The sinews on the vertebral spines had disappeared and the cover of sinews on the whole skeleton had decreased within the year. The left hind leg visible on the 1999 photograph was, one year later, still in articulation with the pelvis. The right hind leg was also still at the same position, though the amount of skin covering had decreased. In 1999 the right foreleg was lying under the chest; it was still there in 2000. The left foreleg was still in articulation from the shoulder blade down to the hooves but it was displaced somewhat relative to its position in 1999. The skin cover of the metacarpus had almost completely disappeared, but the keratinous hooves were still there.

Figure 1.3: Reindeer skeleton in August 1999.

Figure 1.4: Same skeleton as in fig. 3, August 2000.

The assumption by the present author during the first year of examination, that all the fresh looking reindeer carcasses with soft part covering and skin remnants had died the winter before (see Birks and Penford 1990, 21), has been thus proven