Abstract:
Forensic anthropologists rely on the state of decomposition of a body to estimate the post-mortem-
interval (PMI) which provides information about the natural events and environmental forces that could
have affected the remains after death. Various factors are known to influence the rate of decomposition,
among them temperature, rainfall and exposure of the body. However, conflicting reports appear in the
literature on the effect of body size on the rate of decay. The aim of this project was to compare
decomposition rates of large pigs (Sus scrofa; 60–90 kg), with that of small pigs (<35 kg), to assess the
influence of body size on decomposition rates. For the decomposition rates of small pigs, 15 piglets were
assessed three times per week over a period of three months during spring and early summer. Data
collection was conducted until complete skeletonization occurred. Stages of decomposition were scored
according to separate categories for each anatomical region, and the point values for each region were
added to determine the total body score (TBS), which represents the overall stage of decomposition for
each pig. For the large pigs, data of 15 pigs were used. Scatter plots illustrating the relationships between
TBS and PMI as well as TBS and accumulated degree days (ADD) were used to assess the pattern of
decomposition and to compare decomposition rates between small and large pigs. Results indicated that
rapid decomposition occurs during the early stages of decomposition for both samples. Large pigs
showed a plateau phase in the course of advanced stages of decomposition, during which decomposition
was minimal. A similar, but much shorter plateau was reached by small pigs of >20 kg at a PMI of 20–25
days, after which decomposition commenced swiftly. This was in contrast to the small pigs of <20 kg,
which showed no plateau phase and their decomposition rates were swift throughout the duration of the
study. Overall, small pigs decomposed 2.82 times faster than large pigs, indicating that body size does
have an effect on the rate of decomposition.
