Alligator (alligator mississippiensis) taphonomy: analysis of gnawed and digested bone
Schneider, Carrington Simone
MetadataShow full item record
Understanding the tooth mark morphology and behavior of animal scavenging is essential in forensic analysis during recovery of remains in an outdoor setting. Scavengers are part of the natural process of disarticulation; therefore, further research on these taphonomic agents can aid in the analysis of various postmortem bone modifications. The present study focuses on the classifiable morphologies of American alligator (Alligator mississippiensis) bite marks on bone as a method of clearly distinguishing bite marks from other scavengers, specifically canids. Based on previous research, the bite marks of American alligators include punctures, pits, and scoring; however, American alligators also have potentially diagnostic bite marks including bisected mark and hook scores. The sample for the present study consisted of feeding five adult American alligators, aged at least fifty years old, and four nine-year-old American alligators located at the Edisto Island Serpentarium in Edisto Island, South Carolina. The bones fed to the alligators included: thirty-three commercially available white-tailed deer (Odocoileus virginianus) partially fleshed long bones, which included articulated radii and ulnae, femora, tibiae, and humeri; fifteen pounds of partially fleshed white-tailed deer back ribs; and twenty-five pounds of mostly fleshed white-tailed deer neck bones. Additionally, six articulated pig (Sus scrofa) fully fleshed hind limbs were included in the present study. The alligators were typically fed three days a week during the duration of the study. Once the bones were gnawed on by the alligators and left alone in their enclosures, the bones were collected by the serpentarium personnel and stored for analysis. After bones were macerated, the author observed and measured the morphologies of the tooth marks on the bone surface and observed each tooth mark. There was a total of 412 tooth marks observed on all bones. The most frequent tooth mark observed on all bones were pits, followed by punctures, scores, furrows, hook scores, and bisected marks. The results indicate that American alligators have the potential to leave identifiable marks; however, crocodylian species also leave some tooth marks that are morphologically indistinguishable from other mammalian carnivores. The patterns of tooth marks were distinguished from other mammalian carnivores based upon previously published literature, such as Njau and Blumenschine (2006), Drumheller et al. (2014), Delaney-Rivera et al. (2009), Dominguez-Rodrigo and Piqueras (2003), and Pobiner (2007). A paired t-test was run to statistically compare the frequencies of tooth marks from previous crocodylian studies and descriptive statistics are provided to analyze the tooth mark measurements. The present research demonstrates the potential of tooth marks to identify the activity of American alligators.