Taphonomic analysis of Sus scrofa scavenging behavior and corresponding tooth mark patterns on skeletal remains
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Abstract
The present research examined the taphonomic effects of pig (Sus scrofa) scavenging on skeletal remains. There is extensive research about common vertebrate scavengers such as canids, felids, and rodents, but data on pig scavenging, especially in the United States, are limited. One way to differentiate between the scavenging activity of pigs and other vertebrates is to examine and measure tooth mark patterns and gnawing characteristics. The present study hypothesized that pigs create tooth marks that are located more frequently as well as are larger in size on the epiphyses of long bones, spinous processes of vertebrae, and sternal ends of ribs than the diaphyses, centra, and heads/shafts. It was also hypothesized that pigs damage bones in a manner that is distinguishable from other common scavengers such as canids.In the present study, a sample of 100 Gloucestershire Old Spot heritage pigs from Codman Community Farms in Lincoln, Massachusetts were given a variety of white-tailed deer (Odocoileus virginianus) bones to gnaw on, after which their scavenging behavior was recorded. The pigs were fed 100 disarticulated long bones, 10 half rib cages, and 10 necks for a minimum of 575 elements. The bones were cleaned and analyzed for tooth pits, punctures, scores, and furrows, and other damage at Boston University, Chobanian and Avedisian School of Medicine. Photographs of the bones and tooth marks were taken and administered through the open-source imaging processing program ImageJ to measure the length and breadth of each tooth mark. Statistical analyses were conducted to determine if the location of the bone was a statistically significant factor in the frequency and size of pig tooth marks, and to distinguish between pig and canid gnawing by comparing their tooth mark sizes and locations.
Pits were the most prevalent tooth mark produced by the pigs (63.5%), contrary to previous research. There was a statistically significant difference between the number of tooth marks and the location on the bone. Pits (p = 0.042), punctures (p = <0.001), and furrows (p = 0.003) on the long bones were more commonly found on the epiphyses; pits (p = 0.038) on the vertebrae were more commonly found on the spinous processes; and pits (p = <0.001) and scores (p = <0.001) on the ribs were more commonly found on the heads/shafts.
It was also found that the relationship between the size of tooth marks on long bones and the location of the bone was statistically significant. Pit length (p = 0.032), breadth (p = 0.021), puncture breadth (p = 0.023), and score length (p = 0.017) and breadth (p = <0.001) on the long bones were larger on the epiphyses than the diaphyses. Only score length (p = 0.002) on the ribs was significantly larger on the sternal ends than the heads/shafts, so the size of tooth marks on ribs was not dependent on the location of the bone. When comparing canid tooth marks from previous research (Andrés et al. 2012; Sala et al. 2014; Yravedra et al. 2014) and the pig tooth marks from the current study, the results indicated that the two scavenger taxa could be confidently distinguished if epiphyseal pit length and breadth (p = <0.001 to 0.002) are measured and compared. If pits on the diaphyses (p = <0.001 to 0.754) and score breadth on the diaphyses (p = <0.001 to 0.437) were being used to compare, then caution should be taken. Overall, the average length (1.43 mm) and breadth (0.92 mm) of pits on the epiphyses produced by pigs were significantly smaller than canid pit length (2.40-3.61 mm) and breadth (1.90-2.70 mm).
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2025