AVIAN SCAVENGERS

Tooth marks and bone-breakage caused by carnivores have been important topics of research in African neotaphonomy, but North American research has typically been limited to the effects of wolves. This paper presents the results of actualistic feeding experiments with North American wolves, coyotes, mountain lions, bobcats, grizzly bears, and black bears which were fed articulated limb elements of cattle and sheep. This research illustrates that important differences in feeding behaviors exist between carnivore families. Wolves and coyotes gnaw at soft tissue on bones with their posterior dentition and utilize their paws frequently to hold down limbs for leverage when pulling tissue away. Mountain lions and bobcats do not utilize their paws for leverage to remove flesh and instead gnaw on the entire limb with all their teeth in unison. Black bears employ their paws to hold, grasp, and manipulate the limb to gnaw away at soft tissue with their incisors, and grizzly bears leave impressive furrowing marks on the proximal and distal ends of limb elements. A clear understanding of how each taxon of carnivore uses its dentition and jaws to create bone modification is necessary for distinguishing taxon-specific taphonomic patterns in North American archaeological assemblages.

This paper reviews the use of faunal remains as fabric indicators in fossil-bearing cave deposits. Faunal remains, once deposited underground, conform to colluvial slope particle dynamics and develop recognisable fabric patterns. Assessment of fabric patterns has been shown to be a powerful tool for deciphering depositional processes. The hominid-bearing cave deposits of the Cradle of Humankind, South Africa have yielded some of the most important hominid fossils yet discovered, but are renowned for their stratigraphic complexity. In these contexts, faunal remains have primarily been used in more conventional taxonomic and taphonomic analyses. In addition to their potential for ex situ analysis, faunal remains can represent a valuable component for in situ analysis where natural clasts are unsuitable as fabric indicators. This paper presents the first application of biofabric analysis to the plio-pleistocene palaeocave deposits of the Cradle of Humankind, South Africa. Data from two depositionally distinct deposits found in one of the deeper, more stratigraphically complex areas of the Sterkfontein Caves are presented. Detailed analysis of the biofabric, applied during stratigraphically sensitive excavations, is shown to help determine depositional processes, identify probable source deposits and slope formation dynamics, and assess underlying receptacle morphology. This in situ analysis is a simple yet useful tool for increasing stratigraphic resolution in these complex and challenging depositional environments.

During a three week long experiment, a male bovine head was scavenged by an adult Griffon vulture. Twenty five linear scavenging marks were identified on the defleshed cranium and mandible, ranging in length from 2 to 31 mm with an average of 9.02 mm. Based on the experimental observations, the following criteria may be used for diagnosis of vulture scavenging marks: a _/ cross-sectional shape, tapered width, a tendency toward clustering into parallel sets of 2-4 lines, and the presence of V- or L-shaped double lines. Although reliable identification of a single line as a vulture scavenging mark is impossible, a number of features meeting these criteria may allow for a more confident diagnosis. Scavenging lines appear significantly longer on more exposed areas of the cranium, such as the frontal bone in this experiment, and shorter on less accessible areas, such as the mandible.