Nut Cracking Tools Used by Captive Chimpanzees (Pan troglodytes) and Their Comparison with Early Stone Age Percussive Artefacts from Olduvai Gorge

Abstract

We present the results of a series of experiments at the Kumamoto Sanctuary in Japan, in which captive chimpanzees (Pan troglodytes) performed several nut cracking sessions using raw materials from Olduvai Gorge, Tanzania. We examined captive chimpanzee pounding tools using a combination of technological analysis, use-wear distribution, and micro-wear analysis. Our results show specific patterns of use-wear distribution across the active surfaces of pounding tools, which reveal some similarities with traces on archaeological percussive objects from the Early Stone Age, and are consistent with traces on other experimental pounding tools used by modern humans. The approach used in this study may help to stablish a framework with which to interpret archaeological assemblages and improve understanding of use-wear formation processes on pounding tools used by chimpanzees. This study represents the first direct comparison of chimpanzee pounding tools and archaeological material, and thus may contribute to a better understanding of hominin percussive activities.

Analysis of wild macaque stone tools used to crack oil palm nuts

“…The removals either occur along naturally acute angles, resulting in small conchoidal removals, or are detached from natural oblique intersections and can be considered typical hammerstone detachments ( sensu [ 46 ]). They most likely occurred as a result of mis-hits or oblique strikes on a nut, resulting in forceful contact between the hammerstone and a stationary stone anvil [ 43 ]. Two hammerstones possess percussive damage that can be considered similar to hammerstones with fracture angles [ 32 , 39 ].…”

“…On the other hand, the difference in the degree and location of percussive damage may also suggest a difference in the manual handling of the hammer during use. The presence of large striations on the macaque hammerstones may also indicate that these tools were handled and used with less precision than those in the Bossou experimental study, with the damage resulting from frequent mis-hits against the anvil [ 43 ].…”

“…Microscopic analysis was conducted on all use-wear sample hammerstones using a low magnification (less than 100×) Leica S9APO stereo microscope equipped with 1–8× objective lenses and a 10× eyepiece, and photographs were taken using a 3.1 Megapixel EC3 digital microscope camera attached to the microscope. Microscopic use-wear was characterized following standardized methods and terminology for percussive and ground stone artefacts [ 41 ], which have been applied successfully to both hominin [ 35 ] and primate [ 42 , 43 ] percussive lithic material.…”

Functional analysis of sandstone ground stone tools: arguments for a qualitative and quantitative synergetic approach

“…Amongst stone tools, GSTs are probably best suited for testing the potential of quantitative techniques in the analysis of use-related surface modifications. Not only they possess an evolutionary and behavioural significance (their use is recorded since the earliest stages of human history, throughout prehistoric times as well as within extant non-human primates 14,[21][22][23] ) but they are also characterized by long-life cycle and potential for multiple uses/used areas. Detailed functional analyses have been carried out on prehistoric GST technology, which shed light on the involvement of macro-tools in a plethora of daily life activities, ranging from food grinding and pounding to pottery burnishing, metal working, wall sanding, etc.…”

3D 360° surface morphometric analysis of pounding stone tools used by Hadza foragers of Tanzania: A new methodological approach for studying percussive stone artefacts

“…Traces of pounding activities in the form of pitted hammerstones and anvils appear early in the archeological record, suggesting pounding had an important role in hominin food processing behavior and ultimately may have contributed to the emergence of stone tool knapping (Marchant and McGrew 2005;Mora and de la Torre 2005). Despite their significance, few attempts have been made to quantitatively study use wear of battered objects used in various food processing techniques (Arroyo et al 2016;De la Torre et al 2013). As our understanding of the significance of plant foods in hominin evolution increases (Hardy and Martens 2016;Henry et al 2014;Schnorr et al 2016;Schoeninger et al 2001;Vincent 1985), food processing techniques such as pounding are receiving growing consideration (Crittenden and Schnorr 2017).…”