Scavenging effects and scattering patterns on porcine carcasses in Eastern Massachusetts

Forensic investigators encountering remains deposited in an outdoor environment face many obstacles, including the scavenging, scattering, and reconcentration of remains by local vertebrate fauna. Scattering rates can vary considerably from region to region, and are highly dependent on the indigenous scavengers present (Haglund et al. 1988; Haglund et al. 1989; Mann et al. 1990; Morton and Lord 2006). In turn, scavenger activity is highly dependent on seasonal changes, rainfall, temperature fluctuations, and environmental stressors such as seasonal resource availability and dietary changes (Brown et al. 2006; Mann et al. 1990; O’Brien et al. 2007). A more thorough knowledge of the variation in scavenging and scattering patterns of the indigenous fauna in different geographical regions would produce a more productive search pattern and increase the recovery rate of scattered remains for those involved in outdoor crime scene investigations. The current study followed and documented the behavior of the indigenous carnivorous birds and mammals, as well as the scattering patterns of these species, in Eastern Massachusetts, using five porcine (Sus scrofa) carcasses. Carcasses were deposited in lightly wooded environments under different depositional settings and tracked by low-light wildlife video cameras and radio transmitter tags attached to the long bones of some of the limbs. The major scavengers of decomposing remains were documented, and the distance and direction of scattered skeletal elements were noted, as well as any secondary depositions. This research was conducted in three phases; the first was a preliminary observation of faunal wildlife and their distribution during the early summer of 2011, followed by one 14-week observation of porcine models during midsummer of 2011 and one 6-week observation of porcine models during late summer and early fall of 2011. Results show that seasonality greatly affects scavenging activity, as carrion deposited in the summer are primarily consumed by the indigenous invertebrate community, causing accelerated decomposition and vertebrate scavenger exclusion. Additionally, though marsupials and avian species fed the longest, coyotes (Canis latrans) produced the most destructive dispersal of carrion. Moreover, although coyotes disarticulated carcasses relatively nearby the original deposition, they sought out outdoor environments that are mostly devoid of human activity to feed upon disarticulated assemblages