Scars on plants sourced for termite fishing tools by chimpanzees: Towards an archaeology of the perishable

Abstract

Chimpanzees are well-studied, but raw material acquisition for tool use is still poorly understood as sources are difficult to trace. This study pioneers the use of information that can be gleaned from plant scars made by chimpanzees while they source vegetation parts to manufacture termite fishing tools. Source plant species, raw material types and locations relative to targeted termite mounds were recorded for populations at Gombe, Issa, and Mahale in western Tanzania. Recovered bark, twig, and vine tools were traced to 29 plant species, while grass sources were indeterminable. Bark extraction scars remained detectable for months, and thus possibly for as long as the plant is alive, while twig and vine scars preserved for a few weeks only. Scars preserve better than tools, given that twice as many plant species could be linked to the former than to the latter. Some source species were exploited across all sites for the same type of tool material, while two species were sourced for different types. Compared to apes at Gombe and Mahale, Issa chimpanzees carried material from twice as far away, perhaps because the Issa habitat is more open and dry, which entails greater distances between suitable raw material sources and targeted mounds. Site-specific tools were based on different raw materials, in two cases sourced from the same species, which could suggest learned preferences for particular tool material. "Archaeology of the perishable" as pioneered in this study broadens the methodological approach of the wider field of primate archaeology to include reconstructions of past animal behavior associated with the production of plant based tools.

Keywords: Pan troglodytes; organic technology; plant scar; primate archaeology; termite fish; tool material.