1. Introduction  Forensic investigations require an understanding of factors that determine rates of corpse decomposition.  One of the key factors in the decomposition process is temperature.  Understanding corpse temperature throughout decomposition is crucial in determining the post mortem interval (PMI) (Tibbett et al. 2004).  Temperature affects the rate in which a corpse progresses through the 4 stages of decomposition: fresh, bloat, decay and dry (Calce and Rogers 2007).  This research was conducted in order to determine how temperature affects the decomposition rate of a porcine corpse above and below ground. Objectives  To measure temperature variation as decomposition proceeds  To compare the temperature variation of different body regions  To compare the above versus below ground temperature profiles Methods  Two 27 kilogram porcine corpses were obtained  Temperature probes from a HOBO 4-channel data logger (Onset Computers) were placed in 5 body regions of each corpse: brain, thigh, gut, chest and subcutaneous layer  Corpses were placed either above ground or in a grave 1.2 m deep in clay soil  The temperature of each region was taken every 4 hours for 114 days  The 10,944 temperature readings were uploaded and analyzed using Instat and Prism software The Temperature of Five Body Regions of a Decomposing Porcine Corpse Above and Below Ground Lindsey Dieso-Ballesteros 1, Joshua Lawrence 2, John Levisky 2, and Bradley Rehnberg 1 Departments of 1 Biological and 2 Behavioral Sciences York College of Pennsylvania Results Figure 1. The mean daily temperatures of the chest region of the corpse above ground. Each value is an average of the 6 temperatures that were recorded daily. Error bars represent a 95% confidence interval. Figure 2. The mean daily temperatures of the brain region of the corpse above ground. Each value is an average of the 6 temperatures that were recorded daily. Error bars represent a 95% confidence interval. Key Points: There is a significant increase in temperatures of the chest and brain region of the above ground corpse when compared to air temperature between days 12 and 17. The buried corpse exhibited an increase over ground temperature only in the brain region throughout the experiment. Figure 3. The average daily temperatures of all the body regions of the buried corpse. Each value is an average of the 6 temperatures that were recorded daily. Error bars represent a 95% confidence interval. Figure 4. The average daily temperatures of all the body regions of the above ground corpse. Each value is an average of the 6 temperatures that were recorded daily. Error bars represent a 95% confidence interval. Key Points: Each of the buried corpse body regions, except the brain, closely followed ground temperature throughout the experiment. All body regions of the above ground corpse exhibited a significant temperature increase over ambient between days 12 and 17. Figure 5. Change in temperature (∆T) of the chest region of both corpses in relation to their environment. The above ground corpse values are the difference in chest region temperature and air temperature whereas the buried corpse values are the difference in chest region temperature and soil temperature in the grave. Figure 6. Change in temperature (∆T) of the brain region of both corpses in relation to their environment. The above ground corpse values are the difference in brain region temperature and air temperature whereas the buried corpse values are the difference in brain region temperature and soil temperature in the grave. Conclusions  Higher tissue temperatures and maggot activity lead to faster decomposition above ground.  The elevation in brain temperature of the buried corpse was likely caused by brain heat produced by soil decomposers which gained access through the eyes, ears and nose.  The brain region is composed of soft, lipid-rich tissues. Other regions consist mostly of muscle and connective tissues. This difference made the brain region prone to higher maggot activity throughout the experiment (Adlam and Simmons 2007). Key Points: Throughout the time when maggot activity was most intense the temperature of both the chest and brain regions of the above ground corpse elevated above ambient temperature by 11-13 °C. Literature Cited Adlam, R. and Simmons, T. 2007. The Effect of Repeated Physical Disturbance on Soft Tissue Decomposition-Are Taphonomic Studies an Accurate Reflection of Decompositoin. Journal of Forensic Sciences 52:1007-1014. Calce, S. and Rogers, T. 2007. Taphonomic Changes to Blunt Force Trauma: A Preliminary Study. Journal of Forensic Sciences 52:519-527. Tibbett, M., Carter, D., Haslam, T., Major, R. and Haslam, R. 2004. A Laboratory Incubation Method for Determining the Rate of Microbiological Degradation of Skeletal Muscle Tissue in Soil. Journal of Forensic Sciences 49:560-565. Acknowledgements The authors would like to thank Mr. Jake Kint for allowing us to utilize his land for this experiment. Intense Above-Ground Maggot Activity Figure 7. Intense maggot activity in the abdominal region of the above ground corpse.