When I started my studies of vertebrate faunal remains recovered from archaeological sites over twenty years ago, I had no idea what taphonomy was nor was I particularly concerned about what are today typically asked questions concerning the preservation and formation of the archaeofaunal record. But as I read the zooarchaeological literature while completing my doctoral dissertation in the mid-1970s, I found an increasing number of papers dealing with taphonomic issues. The fact that since then it has become increasingly difficult to keep up with the ever growing literature on taphonomy is something of a mixed blessing. It is a mixed blessing because (a) we are constantly realigning the relation between what we want to learn and what we think we can learn from the vertebrate faunal remains we recover from archaeological sites, and thus our conclusions tend to be much more strongly founded than even a decade ago (this is good), and (b) it is nearly impossible for any one analyst to conceive of all of the logically possible taphonomic problems that a single reasonably sized assemblage of vertebrate remains might present. The latter is not bad; it just means a taphonomist's and zooarchaeologist's (and thus my) job is much more difficult now than it was a mere decade ago. Simply put, the analysis of zooarchaeological remains is no longer the simple, straightforward task that it was in the 1960s or 1970s. Taphonomic research has found a home in zooarchaeology, and it is here to stay.

Introduction

Many taphonomic processes may affect animal carcasses and bones between the time of animal death and burial of the carcass or bones. Several of the major human biostratinomic factors are discussed in Chapter 8. In this chapter other biostratinomic factors, several of which are natural processes, are reviewed. Discussion is limited to those factors that have been more or less extensively dealt with in the literature. As well, several basic comparative analytic techniques are described at the end of the chapter.

Weathering

Behrensmeyer (1978:153) defines the weathering of bone as “the process by which the original microscopic organic and inorganic components of bone are separated from each other and destroyed by physical and chemical agents operating on the bone in situ, either on the surface or within the soil zone.” Weathering involves the decomposition and destruction of bones “as part of the normal process of nutrient recycling in and on soils” (Behrensmeyer 1978:150).

Introduction

Most faunal remains paleobiologists and zooarchaeologists study are recovered from subsurface contexts. An important taphonomic problem then, concerns gaining an understanding of burial processes. For example, humans do not seem to be the only biological agent that buries animal parts. Sexton beetles (Microphorus sp.) bury rodent carcasses (Milne and Milne 1976), fossorial rodents often die in their burrows and thus are already buried, and trampling (Chapter 9) by any number of biological agents can result in the burial of animal remains. And there are numerous geological processes which result in the burial of animal carcasses and remains (Behrensmeyer and Hook 1992). The burial process is important because not only are bones and teeth placed in the sedimentary matrix in which they undergo diagenetic processes (Chapter 11), but they may be variously moved, reoriented, broken, and/or abraded during burial by the taphonomic agents of burial (Chapter 6).

Burial as a taphonomic process has undergone little intensive study relative to biostratinomic processes that modify vertebrate remains. Straus (1990:261) suggests that depositional and formational processes were initially ignored by archaeologists in favor of the more immediate and interesting task of building cultural chronologies once the deep antiquity of hominids was established in the last half of the nineteenth century.

Introduction

One of the most obvious and visible properties of a faunal assemblage is the frequencies of each of the particular skeletal elements that make up the collection. A complete mammal skeleton, for example, always consists of two humeri, two scapulae, two mandibles, one skull, etc. From this model of relative frequencies of skeletal parts in an individual, one can predict what should be found in a fossil assemblage that contains, for instance, 10 skulls; here, 20 humeri, 20 scapulae, 20 mandibles, etc., should be found if taphonomic processes have not resulted in the removal of certain kinds of bones, and sampling and recovery processes have not failed to find certain skeletal parts. Analysis of skeletal part frequencies, or what are sometimes called skeletal part profiles, has, in the past 15 years, become a major part of taphonomic research. In fact, the references cited in this chapter show that there has been a major burst of publication on this topic in the late 1980s and early 1990s.

Introduction

Modern taphonomic analysis is (sometimes excrutiatingly) detailed, it is extensive, and it is intensive. The number of variables the analyst should and perhaps must consider is large, and tends to increase as the complexity of an assemblage's taphonomic history increases. I noted earlier, for example, that assemblages representing one or a few individual organisms signifying one accumulational and depositional event often tend to be easier to interpret than long-term accumulations consisting of multiple taxa and multiple individuals. It seems that the latter kind of assemblage is more common than the former, therefore the taphonomist may typically be faced with a collection of vertebrate remains that had a complex taphonomic history that may not be analytically discernable.

“Taphonomic change is sequential” (Andres 1992:39). Because taphonomic processes are historical, they are cumulative (effects of some processes obscure or destroy effects of earlier processes) and in some cases, one process is dependent on a preceding one. For example, carnivore gnawing may obliterate butchering marks on bones, or a highly weathered bone is unlikely to be transported to the den of a scavenging carnivore. What a taphonomist studies is how a collection of fossils differs from the living skeletons of animals represented by those fossils, and if and how the population of skeletons differs from the natural biotic population of skeletons.

Introduction

Paleontologists and zooarchaeologists tend to be optimal foragers when choosing a place to collect faunal remains. For the former, it saves time and money. For the latter, it not only saves time and money, but the places chosen are usually selected by an archaeologist because they contain a dense concentration of artifacts; if bones are spatially associated with the artifacts, then they too are usually collected (because they are there and) regardless of their frequency per unit volume of sediment. Typically, few archaeological sites are excavated or collected simply because they contain animal remains. Determining how the animal remains came to be in the locations from which they are collected, regardless of their geographical and geological position when collected, is one of the most fundamental aspects of taphonomic research.

Why are bones densely concentrated in a particular location, but not in surrounding areas? Why are some kinds of bones present or abundant and other kinds absent or rare? Why are some skeletons completely articulated, some partially articulated, and others totally disarticulated? Why are some bones spatially close and others spatially distant from one another? Why are some bones oriented one way and others oriented another way? Why do some assemblages have lots of carnivore remains and others have few relative to the frequency of herbivore remains? This sampling of questions implies a number of variables that might be measured in an analysis of accumulation.

Introduction

The foundations for taphonomic research were laid in the nineteenth and early twentieth centuries with a focus on observations of modern processes that resulted in deposits containing bones with certain modifications (Behrensmeyer and Kidwell 1985). Early taphonomists followed the uniformitarianist approach used by geologists of the nineteenth and twentieth centuries. That approach and its present structure in the service of zooarchaeological taphonomy is reviewed in the second part of this chapter. Prior to that I review several examples of what I consider to be good taphonomic analyses. These illustrate what makes for strong conclusions and lead to a consideration of uniformitarianism and actualism as methodologies for studying the past. This in turn leads to a consideration of ethnoarchaeology and middle-range research. Finally, because actualism and middle-range research ultimately lead to analogical arguments, the structure of such arguments is described.

Examples of taphonomic analysis

The criteria I used to select the examples reviewed were simple. The analysis must be published in a generally available form so that the original can be consulted by interested readers.