Study of the SHK Main Site faunal assemblage, Olduvai Gorge, Tanzania: Implications for Bed II taphonomy, paleoecology, and hominin utilization of megafauna

Abstract

Recent excavations at the SHK Main Site, Olduvai Gorge, Tanzania, have unearthed a dense concentration of stone tools and faunal remains. Here, we describe how the site contributes to the understanding of hominin subsistence strategies and paleoecology during Bed II times (1.78–1.34 Ma). This palimpsestic site is located within, and on the over-bank of, a river channel. Taphonomic analyses suggest that a heterogeneous set of taphonomic agents played a role in the accumulation and modification of the faunal assemblage. Although hominins played a rather marginal part in this assemblage's faunal accumulation and modification, the recovered faunal assemblage includes evidence that is consistent with hominin exploitation of hippopotamus and equid. This evidence underscores the possibility that by 1.5 Ma hominins were diversifying their diet and enlarging their ecological niche by exploiting, probably opportunistically, megafaunal remains more commonly than previously documented. Taphonomic spatial analysis shows differences in bone preservation and modification according to whether faunal specimens were located inside the river channel or on its over-bank. We also show that spatial taphonomic analysis can contribute to the understanding of palimpsest-site formation, as well as to the reconstruction of diverse taphonomic agents responsible for that formation. A comparative analysis of taxonomic diversity between SHK versus other upper Bed II sites supports the notion that the environment was fairly open prior to the beginning of the Bed III deposits. The large number of lithic artifacts concentrated at the SHK Main Site, when considered in conjunction with the small amount of evidence for carcass-processing, suggests that hominins engaged in a diversity of activities beyond butchery.