Older than the oldowan

Evolutionary Anthropology 235

ARTICLES

Older Than the Oldowan? Rethinking the Emergence of Hominin Tool Use
MELISSA A. PANGER, ALISON S. BROOKS, BRIAN G. RICHMOND, AND BERNARD WOOD
Intentionally modified stone tools first appear in the hominin archeological record about 2.5 mya. Their appearance has been variously interpreted as marking the onset of tool use by hominins or, lessrestrictively, the origin of hominin lithic technology.1,2 Although the 2.5 mya date has persisted for two decades, several related but distinct questions about the origin and evolution of hominin tool use remain to be answered: Did hominins use tools before 2.5 mya? Did hominins use unmodified stones as tools before 2.5 mya? Does the earliest appearance of stone tools in the archeological record representthe earliest use of intentionally modified stones as tools? ized occurrences often containing hundreds or even thousands of stone artifacts and associated fossil specimens.5 Low-density sites with fewer than 100 stone artifacts, referred to as scatters, have also been described.6 The artifacts range from well-made flakes with clear striking platforms, bulbs of percussion, and dorsal scars indicativeof multiple prior flake removals from the core7 to amorphous lumps and shattered fragments of exotic raw materials.8 Hard-hammer percussion, the most frequent technique used to manufacture Oldowan-type tools, apparently involved striking a hand-held hammer stone against a hand-held core.9 However, it is likely that some Oldowan tools were made by placing a core against a substrate and then strikingit with another stone or by striking or throwing a stone against a hard surface.9 Microwear analyses suggest that some Oldowan tools were used to process large vertebrates by cutting meat from bone or, using percussion techniques, to gain access to bone marrow.10,11 Other tools may have been used for digging9 or for cutting wood and siliceous plant tissues.11,12 Oldowan tools have been describedin detail elsewhere.13,14 When stone tools are used to process large vertebrates, they often leave distinctive patterns of damage on the fossilized remains.15,16 Therefore, faunal remains showing modifications inconsistent with natural breakage but consistent with stone tool use provide indirect evidence of stone tool use.17 Currently, the earliest such evidence also dates to about 2.5 mya.17 Bonetools dating to 2 to 1.5 mya have also been found in both East and Southern Africa.14,18 Although the bones are not extensively modified,

Using information from primatology, functional morphology, phylogeny, archeology, and paleoanthropology, we argue that before 2.5 mya hominins may have used tools, including unmodified and possibly modified

stone tools (Fig. 1). We consider several scenariosto explain why stone tool manufacture and use might not have left archeological traces prior to 2.5 mya and conclude by suggesting means to test our hypotheses.

Melissa Panger is a Postdoctoral Research Fellow in the Department of Anthropology and the Center for the Advanced Study of Human Paleobiology at The George Washington University. E-mail: panger@gwu.edu Alison Brooks is Professor andChair of the Department of Anthropology at The George Washington University and Professor, Center for the Advanced Study of Human Paleobiology. Research Associate in Anthropology, National Museum of Natural History, the Smithsonian Institution. E-mail: abrooks@gwu.edu Brian Richmond is an Assistant Professor in the Department of Anthropology and the Center for the Advanced Study of Human Paleobiologyat The George Washington University and Research Associate of the Human Origins Program at the National Museum of Natural History, the Smithsonian Institution. E-mail: brich@gwu.edu Bernard Wood is the Henry R. Luce Professor of Human Origins in the Department of Anthropology at The George Washington University and Adjunct Senior Scientist at the National Museum of Natural History, the...