Some archaeologists do not see the value in analyzing animal bones, because they believe there is nothing new to learn from them. It is easy to understand this position when the majority of reports on animal bone data contain merely NISP and MNI lists of “animals eaten.” These projects stop in the early stages of data analysis and fail to interpret the data that these assemblages contain. Every single animal bone assemblage has a story to tell, and only a portion of that story is about what was eaten. Animal bones can be used to address research questions about environments and environmental change as well as economic and ritual activities.
To connect your database of identified animal bones to your research questions requires an eye for patterns. It is likely that only a portion of the assemblage directly addresses your questions, but you need to be able to see through the noisy data to find it. You will also need to know a bit about the taxonomic groups identified, specifically the natural habits and habitats of wild species and domestic species and their cultural uses. Don’t fall into the “animals = food” mind-set; consider ritual uses as well. Don’t forget to look for evidence that natural processes may have affected your assemblage too.
Linking Data to Research Questions
All research is guided by research questions. If you don’t have any research questions of your own, speak with the project director or read up on the current research of the region and time period from which your assemblage comes. If you don’t ask questions of your data, your data will not tell you anything new. Some basic research questions that can be addressed by animal bones are listed below. These are meant to inspire research, not to restrict it to the topics covered.
Sample Research Questions
What environments or microenvironments were exploited?Is there evidence of environmental change?Were fresh kills butchered before or after returning to the home base?Were animals skinned for their hides?Was bone used as a raw material?Were beaver (Castor canadensis) incisors used for woodworking?Was turkey (Meleagris gallopavo) domestication linked to ritual feasting?What wild species were hunted after residents acquired domestic animals?How were domestic herds managed?How much meat was consumed?Are there any obvious ethnic preferences in meat selection and/or butchery?Did members of a clan avoid their totem animal?What impact did new trade relations have on the availability and use of animal resources?
Some of the sample research questions would require a general analysis of each and every animal bone cataloged. Others would require very detailed analysis of a portion of the assemblage. All of these research questions require an adequate sample size to be present in your assemblage before you can attempt to answer them. For example, if your assemblage contains only two beaver (Castor canadensis) incisors, your sample size is too small to test whether they were routinely used for woodworking. If the incisors are complete and show wear from being hafted (attached to a handle) on one end and used for an abrasive task on the other, you can say the incisors were tools. To say they were woodworking tools, you need to compare these wear patterns to those on beaver incisors that were known woodworking tools. To obtain this comparative data, you may need to do some experimental archaeology or seek out some beaver incisor tools that were collected during ethnographic research. Even if your two specimens reasonably match with a similar tool of known use, it is not wise to draw strong conclusions based on such limited data. At this point you have a choice: you can say there is some evidence for beaver incisors to have been used for woodworking at this one site, or you can go in search of additional data. If you really want to learn about incisors as woodworking tools, don’t be limited to your assemblage or your site. There are boxes upon boxes of animal bones in storage that can provide more data.
What is an adequate sample size? Unfortunately there is no magic number or formula for determining what sample size is adequate. The goal is to have a representative sample, one that includes a significant portion of all possible examples. So if your assemblage is from a historic Seneca village, you want to look at beaver incisors recovered from excavations of other historic Seneca villages. You may discover that most of these other sites have unmodified beaver incisors (not used for tools), if they have them at all. This would suggest that either the incisors were not being used for woodworking at these other sites or that incisors as tools were not being disposed of in the manner or frequency that would make them visible in the archaeological record.
Since every archaeological assemblage is already a biased sample, you need to consider how those biases may have reduced the representativeness of what you have before you can determine what a representative sample size is. For example, if these tools were considered a personal item, they may be more commonly deposited in graves than in middens. If graves were not excavated at these other sites, that may explain why these tools cannot be found in those assemblages.
Archaeological studies can often benefit from data collected from other sources too. Ethnographies, studies of living cultures, are especially useful if they exist for cultures that are related to those who inhabited the site you are working on. These studies often detail the ways in which animals were used. Historical documents may also be of value. These may include diaries of travelers or newspapers with advertisements for local butchers. Oral histories are another source of valuable information. If you are not sure that your animal bones constitute an adequate sample size, you can support any conclusions you reach with information from these other data sources.
Background Noise and Outliers
As suggested previously, not all of the data you have produced by cataloging the animal bone assemblage will be relevant to your research questions. It is okay to focus your interpretive efforts on specific aspects of the data. In fact, this can help you to avoid one of the most common traps that new researchers fall into: feeling paralyzed by the data. Thanks to your efforts of identifying and describing an assemblage of animal bones, this data is now accessible to you and to others for future research. For now, find the data that is most relevant to your research question and consider everything else background noise.
Background noise is the large amount of redundant data that can obscure some of the more interesting data. For example, many eastern North American faunal assemblages that date to prehistoric time periods are dominated by fragments of white-tailed deer (Odocoileus virginianus) bones. A good deal of research has already been done on how these deer were obtained, processed, and used by many different cultures. Returning to the need for animal bone assemblages to provide “new” data, if we consider deer as background noise in existing faunal databases, we may stimulate new research on beavers (Castor canadensis), woodchucks (Marmota monax), or other species. But mammals in general have received a fair amount of research. What if we consider all mammals as background noise and focus new efforts on species of birds, fish, reptiles, and amphibians? Ethnographic data suggests that non-mammals had their own roles in prehistoric North American cultures, yet little research has linked these ethnographic accounts to archaeological assemblages. A similar approach can be applied to historic sites. Many of these assemblages are dominated by domestic species of cow (Bos taurus), pig (Sus scrofa), sheep (Ovis aries), and goat (Capra hircus). Much less research has been directed at the wild species that continued to play a role in historic lifeways. Hunting, in many cultures, has not ceased as a form of recreation or as a supplement to domestic meat sources. More research can be done on the domestic species that never end up on a menu, including common and uncommon pets or the collections of small-scale zoos.
One way to find the unusual aspects of your data set is to look for outliers, the data that stands out from the rest. This can be accomplished using a statistics software package—for example, by creating box plots of assemblage data. Instead of showing individual data points, box plots use boxes and lines extending from those boxes to represent the mean and the variation of data points around that mean. By creating box plots of the NISP of different contexts, you can see which taxonomic groups deviate from the mean NISP value for that context. Those taxonomic groups that all have similar NISP values fall within the box plot, and those with significantly higher or lower NISPs will fall above or below the plots. A similar result can be obtained by creating pie charts or bar graphs.
Wild Species: Habitat and Seasonality
If your assemblage contains wild (undomesticated) species, you should become familiar with their natural behaviors in order to assess their presence in your assemblage. Again, I recommend use of the online Animal Diversity Web, although there are many other sources available on the Internet and in print. Read up on the basics of preferred diet and habitat, breeding and hibernation cycles, and known cultural uses of each species. What you read may have you questioning some of your identifications (e.g., does it make sense that a fragment of water buffalo (Bubalus bubalis) was found in a desert region?). This type of reality check can keep you from making grandiose statements about your assemblage that prove false under close scrutiny.
Beyond protecting your professional reputation, information about the lifeways of the species you have identified provides a wealth of information. The presence and absence of certain species can help in recreating the environments that once existed at and around your archaeological site and the habits of the people who used these species. Some species (especially rodents) are very habitat-specific, and their presence in an assemblage may be evidence of trade networks that brought them over long distances or of small-scale environmental change that would otherwise go unnoticed. The breeding, migration, and hibernation cycles of species can also suggest the seasons during which a site was used or a feature was filled. If a species produces young only in the spring, and your feature contains juveniles of that species, age estimations can be used to determine the most likely month or months that those individuals would have died. Be sure to check for taphonomic signatures like weathering that might suggest the bones were left to decompose on the ground surface before they were incorporated into a feature.
Wild species usually have to be brought to any large human habitation. Become familiar with the mechanisms by which this may have occurred by reviewing ethnographic or historical data on the culture(s) associated with the site. Familiarize yourself with the hunting and fishing techniques as well as the customs and cultural meanings associated with these species and their acquisition. Attempt to correlate this data with the taphonomic signatures that you have documented.
Domestic Species: Meat Cuts and Economics
If your assemblage contains domestic (raised by humans) species, you should become familiar with the known uses of these species, which often vary by culture, time period, and region. Many of these animals are raised for meat, but others are raised for milk, eggs, hair, labor, or other means of economic gain. If these animals were being raised on site, assume your assemblage contains only a fraction of the livestock once present. The best of livestock is usually sold at market.
To assess livestock practices you may want to create age profiles of the domestic species in your assemblage. Juveniles can be aged by their stages of bone fusion, and adults can be aged by the wear patterns of their teeth. Once you have determined an estimated age for your specimens, you can tabulate the results by MNI or NISP and compare it to the age profiles of living herds. There is a wealth of data available on herd management strategies. Domestic species that have been professionally butchered usually retain some evidence of that butchery in the form of knife or saw cut marks (see chapter 5). By recording the placement of these butchery cuts it is possible to identify standard meat cuts and recreate patterns of consumption. Be sure to look for historical information about the cost of these cuts as their desirability changed through time (e.g., Gust 1983). For example, while lean cuts of meat are valued in modern times, the fattiest cuts may have been considered the most valuable in the past.
Bone pathologies, irregular bone formations usually due to disease or injury, are more commonly found on domestic than wild species and may be evident in your assemblage. The documentation of any pathological bone is encouraged, for it can reveal some of the difficulties the animal’s owners or consumers were facing. Some pathologies are specific to a condition, and that condition can be revealed through basic visual inspection. Other pathologies require microscopic investigation or DNA testing to reveal their cause.
Commensals: The Animals around Us
While all species can be broken down into the wild versus domestic dichotomy, there are some species that seem to be both. These are our commensal species, animals that can be found living with humans or around human habitations that have little or nothing to do with food, economics, or cultural beliefs. The most extreme example of a commensal species is the rat (Rattus rattus), which infests urban settlements. Less obvious examples may be stray dogs or cats and common backyard animals, including birds, reptiles, and amphibians.
One of the main challenges in interpreting commensal species is that it is difficult to know how much interaction there was between them and the humans around them. Some people encourage commensal species by intentionally providing food, such as is the case with bird feeders. Other people unintentionally encourage commensal species by leaving garbage out or failing to keep their homes clean. Others actively engage commensal species by hunting them for pest extermination, entertaining sport, or dietary supplement.
Taphonomic signatures can help to reveal the nature of any commensal species within your assemblage. If rodents or carnivores were active at the site, gnawing should be evident on some percentage of the assemblage’s mammal bone. If these species were consumed, some percentage of their bones should be charred, unless they were eaten raw, which is highly unlikely. Many commensal species are too small to be butchered and may have been roasted whole. If a commensal species was cared for by humans, this may be obvious in pathological bone, such as a healed fracture, or in evidence that the individual reached an unusually old age.
Animals as Sources of Raw Materials
Animal bone is a sturdy material that has been fashioned into all sorts of functional and decorative items. In places where wood and stone are hard to find, bone has been used to form the framework of houses. In prehistoric times, animal bone has been used for everything from sewing needles to fishhooks and farming hoes. In historic times, animal bone has been used in the manufacture of goods such as bone buttons. Unfortunately, the usefulness of bone has led to such a variety of possible uses that there are no standards (see chapter 5).
Animals provide more than bones for those who are seeking easily accessible raw materials. Hides, furs, and skins are used for houses, furnishings, clothing, and containers. While these goods rarely survive in the archaeological record, their presence can be revealed by the cut marks found on and around the heads and feet of the animals from which they were acquired. Skinning cuts are usually made in places where meat is thin or nonexistent. This results in knife cuts that usually penetrate to the bone and increase the likelihood of leaving evidence of this practice in the archaeological record.
Birds provide a unique resource in their feathers. Depending on the intended use of the feathers, color may or may not be a selective factor in their acquisition. Feathers may or may not have been acquired from dead birds; therefore it may be difficult to see feather acquisition from an archaeological assemblage. Look for the presence of exotic birds or those that are unlikely to have been consumed. Some cultures raised birds for their feathers, so an abundance of bird remains may be another indicator of feather use.
Animals as Ritual Resources
It is impossible to summarize all the ways human cultures have used animals as ritual resources. The variety is seemingly endless. Some rituals involve living animals (the American Groundhog Day), some require harming or killing animals (the Iroquois White Dog ceremony); others include the bones of animals that died at another time (“reading” bones in fortune-telling). There are two basic ways to approach an analysis of the ritual use of animals within your assemblage: inductive and deductive research.
Inductive research begins with knowledge of how the cultures of your region and time period of interest used animals in their rituals. You may acquire this knowledge from previous archaeological analyses, from historical records, or from ethnographies. With this knowledge, determine what taphonomic signatures would remain from these behaviors, such as the development of polish or other forms of use wear. Then look for these taphonomic signatures in your assemblage. Alternatively it may be a specific species that was treated in a ritual way; in that case, quantify the remains of that animal separately from the rest to see if it is more or less common across the site or within a specific context, such as one house within the village.
Deductive research begins with your data and evidence of ritual use that may be evident there, and then it suggests an explanation for the data that may or may not be supported by other existing data. For example, when cataloging the Engelbert faunal assemblage, it became obvious that Anura (frogs and toads) were much more common at that site than expected. When NISPs and MNIs were calculated, it was possible to compare these data to those from other faunal assemblages to confirm the unusually high numbers of these animals within this assemblage. Historical research into the notes of missionaries and ethnographic accounts of food use together with taphonomic analyses suggests that some of these Anura were made into a medicinal soup. Two pots of this soup appear to have been placed within the grave of a young woman.
Be careful to support any of your interpretations of ritual behavior with plenty of data. It is easy to blame ritual for anything that appears unusual, but it is important to follow the theory of Occam’s Razor: the simplest explanation—the one that makes the fewest assumptions—is usually the best explanation.