4,300-year-old chimpanzee sites and the origins of percussive stone technology

Abstract

Archaeological research in the African rainforest reveals unexpected results in the search for the origins of hominoid technology. The ancient Panin sites from Côte d'Ivoire constitute the only evidence of prehistoric ape behavior known to date anywhere in the world. Recent archaeological work has yielded behaviorally modified stones, dated by chronometric means to 4,300 years of age, lodging starch residue suggestive of prehistoric dietary practices by ancient chimpanzees. The "Chimpanzee Stone Age" pre-dates the advent of settled farming villages in this part of the African rainforest and suggests that percussive material culture could have been inherited from an common human-chimpanzee clade, rather than invented by hominins, or have arisen by imitation, or resulted from independent technological convergence.

Fig. 1.

Map of Noulo. Excavation grid covers 100 m². Solid black squares indicate granitoid specimens. Circles represent quartz specimens. Asterisks indicate feldspar-rich granitoids, and diamonds indicate laterite pieces. Each spot represents one piece, but in the case of shatter or refitted specimens, the number of specimens per spot is as follows: no. 6, 2; no. 8, 3; no. 34, 59; no. 35, 29. Light gray shading indicates granitoid shatter. Triangles and dark gray shading indicate quartz shatter, representing specimens reduced by humans shown on Table 2 as nos. 35, 29; 38, 27; and 45, 26.

Fig. 2.

Selected thrusting percussion products. Stone specimen ID, as it appears on Table 2: A, 2; B, 4; C, 11; D, 12; E, 25; F, 20; G (two pieces), 23; H, 17; I, 28; J, 29; K, 14; L, 27; M, 13. (Photograph by Gerald Newlands, Department of Archaeology, University of Calgary.)

Fig. 3.

Starch grains extracted from archaeological specimens amount to 370 grains, and these can be classified into three types: Type 1 (A–E), comprising subrounded to subangular, medium size grains (10–25 μm) with a smooth to rugose surface and distinct quandrangular, hexagonal, or octagonal faceting. The hylum (or geometric centre of the grain) often supports a single cavity, a slit, or several fissures forming a Y, cross, or star-like patterns. The arms of the cross are often straight, but sometimes they take on wavy and hooked morphologies. Type 2 (F–J) is a small (5–10 μm) to medium (10–25 μm) spherical grain with a smooth surface. It shows a centric slit or fissures. Its arms are straight and widen out toward the periphery. Type 3 (K–O) is a medium (10–25 μm) to large (25 μm) lenticular grain with a characteristic wide and diffuse cross; sometimes smooth, sometimes with variably marked lamellae. Micrographs from the reference collection illustrate selected examples of one or several morphotypes from the nuts of Parinari excelsa (P, Q, W, and X), Detarium senegalense (R and V), Coula edulis (S and T), and Panda oleosa (U). Stone specimen identification, as it appears on Table 2: A, 20; B, 29; C, 32, D and E, 35; F, 15; G, 7; H, 23; I, 5; J, 7; K, 34; L, 27; M, 3; N, 24; O, 24. (Micrographs by J.M. and Gerald Newlands.)