Estimates of hominid and carnivore involvement in the FLK Zinjanthropus fossil assemblage: some socioecological implications

Abstract

Abstract Studies of Plio-Pleistocene zooarchaeological assemblages indicate that early Homo transported and processed carcass-parts with tools for meat and marrow. Because hominid and carnivore damage frequencies have not been estimated, however, debate continues on the extent and nature of hominid and carnivore involvement in many assemblages, thereby hindering reconstructions of early Homo socioecology. Analysis of hammerstone- and carnivore-induced damage frequencies on all large mammal limb pieces in the FLK Zinjanthropus , Olduvai Gorge, Tanzania, fossil assemblage provides direct estimates of hominid and carnivore involvement. Three patterns are clear: (1) hominid-induced damage on 75% of the limb MNE demonstrates that early Homo habitually processed carcass-parts; (2) carnivore damages and fractures occur on 54% and 8·5% of the limb MNE, respectively, indicating a significant carnivore role in assemblage modification, but not breakage; (3) the lack of carnivore damage on 60% of hominid-damaged specimens implies that early Homo had regular access to meat-rich carcasses. Because social carnivores also habitually transport food, the biological and ecological forcing mechanisms behind these behaviors are examined for implications for early Homo socioecology. Anti-predator defense is a primary factor in the evolution of sociality in the Carnivora (Gittleman, 1989). Thus, food transport from a carcass by a foraging group is an anti-predator strategy that minimizes interspecific competition at carcasses. Similarly, maintenance of a refuge area to which food is transported to mother and altricial young reflects a risk-reduction strategy to protect the young. Early Homo shared these ecological and biological conditions, occupying with its altricial young (Stanley, 1992) semi-open habitats with high predator densities. Thus, the habitual food transport and processing documented at FLK Zinjanthropus suggest that early Homo was subject to these same socioecological mechanisms that require similar group division into two functional units (foraging and care-giving) when infants are present. Processed animal remains at places like FLK Zinjanthropus may not represent provisioning or food sharing, per se, but merely the intersection of two anti-predator strategies. Nevertheless, the ecological and biological conditions, and prerequisite subsistence behaviors were apparently in place for the development of social behaviors originally envisioned by Isaac (1978 a ).