Human Bioarchaeology Analysis

An important method related to excavation of human burials is physical anthropology, sometimes called “bioarchaeology.” Throughout the variety of excavations a number of specialists have analyzed the human skeletal remains to assess the age, sex, and general forensics of Bronze and Iron Age individuals from the Dzhungar Mountain region. Despite the limited sample size excavated thus far, data from our excavations in Kazakhstan is of considerable value in obtaining a pooled regional sample from the Koksu-Zhalgyzagash River Valley. While it is of great importance to document these materials as a regional representative, it is also our goal to collect new data from older collections, as it is imperative to establish a baseline of normal biological variation in the Eurasian steppe.

Horseback riding:
The mode and timing of the development of horseback riding in the Eurasian Steppes is a subject of considerable debate.  To date, debates concerning the chronology and ubiquity of horse riding during the Bronze Age in various regions of the Eurasian steppe have been limited to three lines of inquiry: faunal studies (e.g. fauna skeletal morphology and herd dynamics), archaeological studies (horse imagery, ritual deposits, etc.), and archaic texts. However, previous studies have not drawn correlations between the archaeological context and the potential physical effects of riding horses on the human population itself, either due to the non-existence of relevant data, or because the effects of riding on the human skeleton are less discussed among central Asian scholars.

The remains at Begash may contribute to this debate by offering evidence for horseback riding on the steppe.  The femurs from Begash show the development of unusually strong muscle attachments involved in adduction of the lower limbs, a morphology which has been associated with horseback riding in some Native American populations.  Although we are seeking more data for a wider sample set, such indications across this region might signal the advent of riding horses among eastern Kazakh pastoralists of the Bronze Age—a behavior that would have changed landscape use among these populations.  However, it is of critical importance to assess this morphology within the context of a larger spatial and temporal comparative sample.
 

Migration: 
Traditional accounts have explained Bronze Age population history as a demic expansion from western Eurasia into Central and eastern Asia, but more recent evidence indicates that this view requires modification.  Several methods are available to understand local and regional population history from bone and tooth samples.  The methods we are exploring include 1) trace element analysis, 2) stable isotope analysis, 3) DNA analysis and 4) Standard osteological analysis.  These analyses will help to establish a baseline for geographic and biological distances among and between local and regional samples. Isotopes of elements such as strontium can determine geographical place of origin of individuals.

Tooth enamel is resistant to diagenetic changes, thus it will be extracted from teeth and used for analysis.  Because tooth enamel forms in childhood, isotope values in tooth enamel will reflect childhood residence, while later bone formation and remodeling indicates adult locality.  Since bone mineral and dental enamel oxygen isotope values reflect the oxygen isotope values of the water that a mammal consumes, oxygen isotopes have the potential to identify migration, since bone and enamel record the different oxygen isotope values of the different regions.  Movement from one climatic zone to another will manifest oxygen isotope values in tooth enamel, which will reflect childhood residence compared to adult locality. 

Beyond isotopic studies, there are often small amounts of DNA surviving in bone and teeth which may prove useful to understanding populational affinity and population history of skeletal samples.  The use of metric and non-metric data can also be useful indicator of population affinity and regional microevolution, when applied across appropriate datasets.

Subsistence Patterns:
Pastoral nomads are thought to have limited consumption of agricultural products. Osteological samples can serve to directly test this model, since stable isotope analyses of bone and tooth collagen can be used to reconstruct past diets. Stable isotope analyses in modern and archaeological studies of diet may determine the sources of carbon found in bone tissue by measuring the ratios of stable carbon isotopes such as 13C and 12C and also distinguish between C3 and C4 photosynthetic-pathway plants.  This method can detect the proportion of dietary intake from domesticated plants, which utilize the C3 pathway (i.e., millet), and likely reflects dietary intake from approximately the last ten years of life. 

Standard Osteological Analysis and documentation of dental pathology (or the lack thereof) can also serve as a rough guide to subsistence pattern.  Generally speaking, diets high in fermentable carbohydrates are highly cariogenic.  Thus, prehistoric agriculturists generally exhibit higher rates of dental caries than contemporaneous groups of non-agriculturalists.


Discovery Highlights:

Horseback riding:
The mode and timing of the development of horseback riding in the Eurasian Steppes is a subject of considerable debate.  To date, debates concerning the chronology and ubiquity of horse riding during the Bronze Age in various regions of the Eurasian steppe have not drawn correlations between the archaeological context and the potential physical effects of riding horses on the human population itself. The remains at Begash may contribute to this debate by offering evidence for horseback riding on the steppe. The femurs from Begash show the development of unusually strong muscle attachments involved in adduction of the lower limbs, a morphology which has been associated with horseback riding in some Native American populations.

Migration: 
Several methods are available to understand local and regional population history from bone and tooth samples.  The methods we are exploring include 1) trace element analysis, 2) stable isotope analysis, 3) DNA analysis and 4) Standard osteological analysis.  These analyses will help to establish a baseline for geographic and biological distances among and between local and regional samples.

Subsistence Patterns:
Pastoral nomads are thought to have limited consumption of agricultural products. But osteological samples can serve to directly test this model, since stable isotope analyses of bone and tooth collagen can be used to reconstruct past diets. Osteological analysis and documentation of dental pathology (or the lack thereof) can also serve as a rough guide to subsistence pattern.