STUDIES IN TAPHONOMY: BONE AND SOFT TISSUE MODIFICATIONS BY POSTMORTEM SCAVENGERS

This study documented animal scavengers at the University of Tennessee’s Anthropology Research Facility. Remotely-captured digital video and still photography equipment was stationed at the outdoor human decomposition facility intermittently from September 2003 through October 2009. The primary scavengers of corpses were identified as the northern raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), brown rat (Rattus norvegicus), and white-footed mouse (Peromyscus leucopus); and the primary scavenger of skeletal remains was the eastern gray squirrel (Sciurus carolinensis). Among these species, the raccoon was the dominant scavenger and is the focus of this report.

The captured imagery of raccoons documented four primary feeding behaviors at human remains: 1) scavenging soft tissue, 2) foraging in body cavities for late instar maggots en masse, 3) foraging for individual prepupae as they migrated away from the corpse, and 4) foraging for prepupae and puparia and other insects burrowed beneath ground litter and in the soil. As expected, these behaviors were largely sequential in appearance and their presence or absence depended on the conditions under which the corpse decayed, e.g., foraging for insect larvae did not occur at bodies placed in winter because few maggots were present.

Raccoons at the facility preferentially scavenged on the musculature of relatively fresh bodies. Their feeding sites often appeared atypical of a mammalian carnivore, because once they chewed a hole through the skin, they repeatedly placed a forepaw—even a forelimb—deep inside the wound and extracted tissue by way of the newly-formed hole. Although fresher bodies were more extensively scavenged, raccoons modified corpses throughout flesh decomposition—especially, by chewing the fingers and toes.

Bodies placed during winter were more intensively scavenged by raccoons in terms of total tissue removed and bone damage than those placed during fall or spring. Positional disturbances were noted at many bodies, but those placed in the spring incurred greater and more rapid skeletal disturbance and scatter due to warming temperatures and raccoons’ foraging within body cavities and the soil for maggots and pupae.