Porcine Decomposition Rates as an Estimate for Human Post-Mortem Interval in Northern Arizona
Faculty Mentor Name
Hillary Eaton
Format Preference
Poster
Abstract
Rates of human decomposition vary by ecosystem, yet data from Northern Arizona remain limited compared to the Arizona Sonoran Desert. This study monitored the decomposition of two Sus scrofa domesticus placed in a high-desert environment beginning in early February, with one specimen in direct sun and the other in shade; both were clothed to simulate human remains. Environmental variables monitored included air temperature and humidity, soil temperature, moisture, and pH, UVA/UVB rays, luminous flux per unit area (LUX), and daily photographic documentation.
Rain and snow during February and March inhibited early decomposition. As temperatures increased, the sun-exposed pig decomposed faster than the shaded pig, likely due to increased light intensity and ultraviolet exposure. Bloating persisted for 36 days, with advanced decomposition occurring from days 49 to 187, characterized by mummification, adipocere formation, and abdominal cavity collapse. Skeletonization and mummification occurred earlier in the sun-exposed specimen on day 58 and 75 compared to days 65 and 77 in the shaded specimen, while extreme decomposition occurred around day 117 for the sun specimen and day 221 for the shaded specimen. Decomposition progressed more slowly in Northern Arizona than reported for the Sonoran Desert.
Blowfly activity began within 12 hours, followed by ants from days 37 to 185 and dermestid beetles from days 79 to 265 in the sun specimen and up to day 341 in the shaded specimen. Soil conditions showed minimal change. These results provide baseline data for post-mortem interval estimation in Northern Arizona’s high-desert environments. Decomposition scoring and PMI calculations are on-going, and further research is needed on decomposition starting in the summer to better characterize seasonal effects on decomposition.
Porcine Decomposition Rates as an Estimate for Human Post-Mortem Interval in Northern Arizona
Rates of human decomposition vary by ecosystem, yet data from Northern Arizona remain limited compared to the Arizona Sonoran Desert. This study monitored the decomposition of two Sus scrofa domesticus placed in a high-desert environment beginning in early February, with one specimen in direct sun and the other in shade; both were clothed to simulate human remains. Environmental variables monitored included air temperature and humidity, soil temperature, moisture, and pH, UVA/UVB rays, luminous flux per unit area (LUX), and daily photographic documentation.
Rain and snow during February and March inhibited early decomposition. As temperatures increased, the sun-exposed pig decomposed faster than the shaded pig, likely due to increased light intensity and ultraviolet exposure. Bloating persisted for 36 days, with advanced decomposition occurring from days 49 to 187, characterized by mummification, adipocere formation, and abdominal cavity collapse. Skeletonization and mummification occurred earlier in the sun-exposed specimen on day 58 and 75 compared to days 65 and 77 in the shaded specimen, while extreme decomposition occurred around day 117 for the sun specimen and day 221 for the shaded specimen. Decomposition progressed more slowly in Northern Arizona than reported for the Sonoran Desert.
Blowfly activity began within 12 hours, followed by ants from days 37 to 185 and dermestid beetles from days 79 to 265 in the sun specimen and up to day 341 in the shaded specimen. Soil conditions showed minimal change. These results provide baseline data for post-mortem interval estimation in Northern Arizona’s high-desert environments. Decomposition scoring and PMI calculations are on-going, and further research is needed on decomposition starting in the summer to better characterize seasonal effects on decomposition.