Bonobos innovate, plan, and transmit tool use to solve an extractive foraging task

Lara Zanutto, Jake A. Funkhouser, Erik P. Willems, Ava Moser, Crickette Sanz, Zanna Clay, Kathelijne Koops

The evolutionary origins of tool use remain poorly understood. Drawing inferences from living apes is challenging due to striking differences between chimpanzees (Pan troglodytes) and bonobos (P. paniscus), our two closest living relatives. Chimpanzees routinely use tools in both the wild and captivity. Conversely, wild bonobos rarely use tools, whereas captive bonobos show diverse tool use. We examined the individual (i.e., age, sex, and rearing history), social (i.e., past and present exposure to conspecifics using tools), and environmental (i.e., tool availability) tool-use drivers in sanctuary-living bonobos using a novel group-based extractive foraging task. Tool use was more frequent in adult females than in males, in human-reared than in mother-reared immatures, after greater exposure to tool use, and when tools were provided. Hence, tool use in sanctuary-living bonobos is driven by social learning opportunities and developmental biases, providing insight into the conditions that may have favored the emergence of tool use during hominin evolution.
Keywords: bonobos, tool use, extractive foraging, rearing history