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Bioarchaeology: Human Remains

Burials Illustration The artifacts below are among those that were recovered from contexts closely associated with the burials. Human remains present at the site represent at least four and as many as five individuals. Three of those individuals are represented by more-or-less complete skeletons, whereas the remaining two are represented by individual bones (one long bone fragment and one skull fragment). The three sets of more complete remains (illustrated at left) were analyzed in two ways to learn as much as possible about the age, sex, and stature of these individuals, and also to reconstruct aspects of their dietary histories. This last bit of information can be very important for determining whether, for example, these people originally came from coastal areas or whether they mostly ate the kinds of plants and animals that can be found around San Marcos today. Understanding the individuals' past diets makes inferences to their geographic history; for example, an individual found in Central Texas whose remains' stable isotopes were characteristic of marine environments indicates that this particular individual traveled a relatively great distance. In Central Texas, this is about as close to identifying what culture a person belonged to in prehistory as archaeologists get, because little is known about the groups that lived in Central Texas beyond about 500 years ago. Today, DNA helps identify cultural affinity of a sample with a modern population, and this is feasible only because there is an enormous database to compare a sample against. Extending this practice into prehistory would require DNA samples of a great amount of prehistoric Native American remains (extracting such samples from what portion is preserved is another consideration), and it also assumes that these populations are genetically distinguishable. Currently, such a study is not justifiable.

Artifacts Found near BurialsDescriptions

Measurable and non-measurable skeletal features and characteristics provide clues for determining a number of an individual's traits including and not limited to biological sex, stature (height/size), age, and diseases. Without naming each diagnostic element or component, the descriptions below will provide Zatopec's individuals' traits, where determinable.  Individual 1 was buried in a flexed (or fetal) position beneath a layer of rocks that may have been deliberately laid over this person as a cairn. This person was determined to be a male due to the skeleton's general robusticity. A number of skeletal features and characteristics indicate that Individual 1 was approximately 30-50 years old at death, and was approximately 5' 5" to 5' 9" in height. Individual 2, buried adjacent to and slightly on top of Individual 3, was determined to be a female due to overall size and gracility (slenderness). This woman was approximately 20-25 years old when she was buried in a loosely flexed position. Her estimated stature was 4' 9" to 5' 3". Individual 3 was also buried in a flexed position immediately beneath and adjacent to Individual 2. This person was determined to be a slightly older female who died between the ages of 25-45. Her stature is indeterminable due to the incompleteness of her skeleton. Individuals 1 and 3 proved to have been buried approximately 1300 years ago, while Individual 2 was buried around 1200 years ago. The physical closeness of these three burials, plus the associated dates, clearly show that prehistoric peoples returned to this site repeatedly during this important period, and that this specific location had been set aside for this purpose.

Stable Isotopes Stable Isotopes

An analysis of stable carbon and nitrogen isotopes in bone (any kind of bone) provides a glimpse into paleodiets, paleoclimates, and paleoenvironments. First, it should be understood that both carbon and nitrogen are atmospheric gasses that are used differently by a variety of plants, which compose the bottom of the food chain. Once a plant "fixes" (consumes) isotopes from either element, that "fixed" element enters the food chain. As people consume plants directly and also consume animals that fed on plants, traces of their diets, as reflected by different kinds and quantities of isotopes, are recorded in their skeletal structure. The material structure of skeletons changes through time as old bone cells are replaced by new cells. When a person is alive, it takes tens of years for the composition of bones to cycle through; once an individual stops consuming and producing bone (when they are dead), the cycle stops and the last decade or so of that individual's dietary history is recorded. Archaeologists from the Center for Archaeological Research, University of Texas at San Antonio, have been compiling data on the dietary behavior of prehistoric individuals by investigating isotopic compositions of bone. Human remains from Zatopec were first analyzed, and then compared to this existing database.
 
Results from the analysis of stable carbon and nitrogen isotopes in the remains from Zatopec showed that all the individuals practiced similar dietary behaviors, and that these were all characteristic of inland subsistence strategies. With some variation, the isotopic signatures of all three individuals suggest that their diets were primarily composed of inland plant and animal species and supplemented by riverine resources. This is exactly the mix one would expect to find in the San Marcos area.