The effects of taphonomic color alteration upon skeletal recovery rates during surface searches

Previous research shows that even expert-level recovery teams can miss osteological evidence. The present research examined recovery rates and distances using dispersed nonhuman (pig [Sus scrofa], white-tailed deer [Odocoileus virginianus], and mule deer [O. hemionus]) bones with different taphonomic color alteration. Searching was done by a Special Emergency Response Team of the Massachusetts State Police during researcher-guided walk-throughs in a simulated outdoor surface scene. The authors hypothesized that sun-bleached bones would be recognized from the greatest distances due to their starker contrast from natural leaf litter as opposed to control bones or those with soil/decomposition staining. The control sample was unaltered, dry bone without significant staining, and the stained bones had variable brown color from decomposition and/or shallow burial. The sun-bleached bones were spotted at an average distance of 8.76 m ± 7.75 m, while soil/decomposition-stained bones were spotted at 4.09 m ± 2.79 m and the control sample at 6.73 m ± 5.40 m. As determined by a two-way ANOVA test, the interaction between bone color and distance was significant (p < 0.001). Sun-bleached bones had a 100.0% recovery rate (60/60), control bones 96.7% (58/60), and soil/decomposition-stained bones 70.0% (42/60). In addition, bone type also had a statistically significant effect on distance (p < 0.001), and therefore the likelihood of being recovered. Even expert-level recovery teams can miss osteological evidence during surface searches, with natural bone camouflage factoring into recovery success rates. As a result, increased training and education surrounding taphonomically altered bones is necessary for all personnel involved in forensic surface searching.