Probabilistic models of seasonal <Emphasis Type="Italic">Bison</Emphasis> exploitation based on fetal prey osteometry and reproductive phenology

Seasonality studies are a staple of Great Plains archaeology, but obtaining evidence for seasonal food procurement is challenging. This study explores seasonality through the lens of fetal bison remains. A method is developed that produces intra-annual probability distributions for the date of fetal death. These distributions are informed by osteometric data from fetal bison in archaeological contexts, fetal skeletal growth curves, and data-driven models of bison conception dates. Probabilities can be assigned to seasonality hypotheses by examining date intervals across these intra-annual distributions. This method is implemented through an R program and applied to seasonality hypotheses at three archaeological sites containing fetal bison remains: Big Goose Creek (Wyoming), Baker Cave III (Idaho), and the Upper Tucker Site (Texas). Unlike previous efforts to infer seasonality from fetal bison remains, this method provides explicit probabilities showing the level of agreement between the osteometric data and seasonality hypotheses. This probabilistic approach could be extended to seasonality studies involving other animal taxa both within and outside of North America.