In fact, scavengers and other decomposers occupy the dominant trophic position when they are included in food web analyses ( Wilson and Wolkovich, 2011). It transfers significant amounts of energy between trophic levels (i.e., positions within a food web for example, herbivores or carnivores). Scavenging accelerates nutrient cycling, disperses concentrated nutrients, and dilutes pathogenic organisms associated with decomposition ( Selva et al., 2005). Scavengers make important, although historically underestimated, contributions to the ecosystem. DiGangi, in Forensic Taphonomy and Ecology of North American Scavengers, 2018 Scavenging and Ecology At times, a search for additional scattered remains is necessary to recover missing parts of the skeleton needed to complete the confident identification. When unidentified remains are discovered, even with extensive scavenger damage, the opportunity to complete a scientific identification by comparison of antemortem and postmortem radiography still exists. Cooperation among the radiologist, anthropologist, and pathologist resolves uncertainties. Once recognized, the scavenger-induced skeletal changes may be correctly classified and the search for other features of importance in the death investigation may proceed. Radiologically, bone alterations created by scavengers must be recognized as artifacts and not misinterpreted as features associated with the cause of death or be confused with other antemortem or postmortem trauma. Radiograph of assorted bones from scattered skeletonized remains shows perforated, crushed, and irregularly splintered margins of portions of ribs and clavicle. Later the abdomen, pelvis, and thighs are consumed with the lower extremities disarticulated and transported.įigure 9. Canids first deflesh the head, neck, and upper thorax after which the upper extremities are dismembered and transported. The magnitude of the damage depends upon tooth morphology, jaw mechanics, and the size and strength of the particular canid. In general, the longer the interval between death and discovery, the greater the amount of damage done by canid scavengers. In contrast to rodents, canids cause considerable damage. Rodents rarely scatter human remains but on occasion transport the small tubular bones of the hands and feet. Rodent scavenging activity results in characteristic regular parallel groves of uniform pitch extending from the inner surface of a bone to its outer surface. Rodents produce nearly all their damage with their incisors ( Haglund, 1992). The two major scavengers are rodents and canids. Likewise, important perimortem skeletal trauma may be obscured or destroyed. These activities confound attempts to investigate the death and identify the individual because antemortem features may be destroyed or lost from the scene. Scavengers alter and scatter human remains. WA Murphy Jr., in Encyclopedia of Forensic and Legal Medicine (Second Edition), 2016 Postmortem Artifacts Created by Scavengers Human presence can also impact the behavior of scavengers, often reflecting scavenger avoidance of human activity, although some species may tolerate or even benefit from an anthropogenic environment. Changes in the composition of the biological community also influence the likelihood of carrion utilization by different members of the scavenging guild by affecting the availability of carrion or alternative food resources, or by affecting the frequency and outcomes of competitive interactions between scavenging species. The timing of the onset of scavenging after death by vertebrate scavengers and their competitors, namely microorganisms and necrophagous insects, is also affected by such variables.
Environmental and climatic variables influence the likelihood of remains being scavenged by any given species. This chapter overviews the effects of several ecological variables on scavenger behavior. Scavenger behavior, and therefore the resultant taphonomic effects on human remains, is heavily influenced by interactions with the scavengers’ environment and other organisms within their biological community. DiGangi, in Forensic Taphonomy and Ecology of North American Scavengers, 2018 Abstract
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