An inter-site comparison of enamel hypoplasia in bison: implications for paleoecology and modeling Late Plains Archaic subsistence

Bison bison mandibular molars from the Late Plains Archaic kill/butchery sites of Buffalo Creek (Wyoming) and Kaplan-Hoover (Colorado) exhibit significant frequencies of dental enamel hypoplasia (DEH), a defect believed to reflect information about physiological status of individual animals. This study provides a methodology to estimate the ontogenetic and seasonal timing of DEH formation in bison dentition. Integration of these estimates with data from bison life history and grassland ecology allows inferences on age- and season-specific factors exacerbating periodic physiological declines that were recorded in the form of enamel hypoplasias. Differences between assemblages indicate regional variability in grassland conditions, with data from Buffalo Creek pointing to recurrent drought that reduced forage capacity and contributed to physiological stress in bison over two consecutive years. Seasons of physiological stress reflected in the DEH correspond to each of the three kill events at the locality, suggesting that predictability of bison behavior in this location was a critical factor in influencing the seasonal timing and location of repeated hunting episodes. Unlike Buffalo Creek, timings of stress episodes are not consistent with season of death in the Kaplan-Hoover bison assemblage, suggesting that favorable grassland conditions were the primary factor influencing timing of this large single-kill event in order to provision for the upcoming winter. DEH analysis represents a developing approach in the construction of models addressing key aspects of local grassland and bison ecology as well as offers unique insights into the hunting strategies and subsistence decisions of Late Plains Archaic foragers.     

Middle Holocene Taphonomy and Paleozoology at the Prairie-Forest Border,the Itasca Bison Site,MN

The Itasca Bison site near the prairie-forest border in central Minnesota is important to understanding the cultural and ecological role of bison in the upper Midwest during the middle Holocene. Recent reanalyses of this assemblage support the original interpretation of a taphonomically complex, fluvially modified site. Despite this taphonmic complexity, the role of humans in the butchering and possible accumulation of some of the bison fauna is also supported, although not as the only mechanism of accumulation. The bison assemblage is slightly biased toward males, and seasonality estimates are spread throughout the year. New direct accelerator mass spectrometry dates indicate a minimum of two highly mixed depositional events: one at 7970–7790 cal B.P. and an earlier event between 8520 and 8180 cal B.P.     

Bison butchery at Cooper,a Folsom site on the Southern Plains

Cooper, a Folsom arroyo-trap bison kill site in northwest Oklahoma is composed of three large-scale kill episodes. The bison bones have been examined for butchering evidence and exploring the butchering pattern. Damage categories to cortical bone are indentation, cut mark, helical fracture, and impact blow. The 99 elements damaged are from 36 carcasses across all three kills, and damage morphology indicates both lithic and bone expediency tools were used in the butchering. Animals are being butchered in an upright position on their stomachs, with transverse and abdominal muscles the focal point. Experimental butchering of a bison replicates the reconstructed sequence and underscores a gourmet butchering style for the Cooper kills.     

Palaeopathology in late Pleistocene and early Holocene Central Plains bison: dental enamel hypoplasia,fluoride toxicosis and the archaeological record

Multiple formative agents are cited for dental enamel hypoplasia (DEH) in modern and fossil mammals. Here, four late Pleistocene-early Holocene bison assemblages from the Central Great Plains are analyzed for DEH and other bone pathologies to investigate the possible influence of chronic fluoride toxicosis, a condition that may have presented a long-term source of duress for prehistoric bison and devalued them as nutritional resources to human hunters. Although DEH is present in all the analyzed assemblages, the lack of corroborating dental and post-cranial anomalies consistent with chronic fluoride toxicosis speaks against it as a primary factor of DEH formation or general ill health in these bison. Rather, maternal nutritional stress, weaning, and seasonal forage condition are invoked as probable promoters of DEH formation. Other identified abnormalities are discussed in reference to their contribution to reduced feeding efficiency and lameness, as are their roles in developing palaeoecological models applicable to archaeological questions about ancient human lifeways.     

Bison Bone Fragmentation and Survivorship: a Comparative Method

Zooarchaeologists usually describe a bone fragment as a particular portion or segment using terminology based on skeletal orientation (e.g. proximal, anterior, lateral). A more precise understanding of bone fragmentation can be achieved by naming portions for discrete anatomical features and defined zones. Since the anatomical features are the diagnostic criteria for identifying and orienting bones, each specimen normally has at least one such portion, and a complete element contains all of them. This recording method facilitates study of the relationship between survivorship and volume density, and it enhances inter-site comparisons. The method employs the minimum number of elements (MNE) and minimum animal units (MAU) across a site-wide aggregate. Although illustrated here with an analysis of bison bones, the method can be adapted for the study of other taxa as well as for inter-species comparisons.