Year of Award

2026

Document Type

Dissertation

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Anthropology

Department or School/College

Department of Anthropology

Committee Chair

Meradeth Snow

Commitee Members

Anna Prentiss, Katherine Baca, Scott Miller, Xenia Kyriakou

Keywords

Biomolecular Degradation, Lubrecht Experimental Forest, Microbial Decomposition, Natural Mummification, Postmortem Interval Estimation, Rocky Mountains

Abstract

This study investigates patterns of decomposition and biomolecular preservation in domestic pig (Sus scrofa domesticus) proxies under varying burial conditions in a cold, seasonal climate. Conducted at the Lubrecht Experimental Forest in western Montana, the project aims to evaluate DNA degradation, microbial activity, and environmental influences across shallow, deep, surface, and secondary burial contexts. Three pigs were placed in distinct burial treatments (surface exposure, partial burial, and full burial), with a fourth site later added following bear disturbance and carcass relocation. Environmental monitoring included temperature, and soil sampling before and throughout the decomposition process. Systematic sampling of bone, soft tissue, and surrounding soil was conducted over a one-year period, with DNA extracted using context-specific protocols. Microbial culturing was performed using nutrient and starch casein agars to assess colony diversity and distribution over time. Decomposition progression was scored using established frameworks (Megyesi et al., 2005; Vass, 2011; Heaton et al., 2018; Behrensmeyer, 1986) and were tested using regional weather data. This multi-method approach seeks to refine our understanding of forensic taphonomy in northern Rocky Mountain environments, where freeze-thaw cycles, seasonal mummification, and high-elevation ecology shape decay trajectories in unique ways.

Decomposition trajectories differed markedly among burial contexts. Surface and partially buried carcasses decomposed more rapidly than fully buried remains, exhibiting earlier insect colonization, accelerated tissue breakdown, and eventual skeletonization or mummification, whereas fully buried remains retained moist tissues and active decay for longer periods. Microbial activity peaked during early to mid-decomposition, producing high colony densities and localized soil acidification before gradually returning to baseline conditions. DNA recovery varied across substrates, with higher concentrations consistently obtained from protected skeletal elements such as the petrous portion and teeth. Regression analyses demonstrated strong relationships between decomposition progression and environmental variables, with climatic predictors explaining up to 93% of variance in decomposition scores and maximum temperature emerging as the most consistent predictor. Microbial colony morphology varied significantly across burial sites but showed limited temporal change, while colony abundance and pigmentation were not significantly associated with DNA concentration or degradation metrics.

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© Copyright 2026 Kaylee M. Hinds