Travel fosters tool use in wild chimpanzees.

Thibaud Gruber,Christof Neumann,Klaus Zuberbühler

doi:10.7554/elife.16371

Thibaud Gruber, Christof Neumann + Show 1 more

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https://doi.org/10.7554/elife.16371

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Abstract

Ecological variation influences the appearance and maintenance of tool use in animals, either due to necessity or opportunity, but little is known about the relative importance of these two factors. Here, we combined long-term behavioural data on feeding and travelling with six years of field experiments in a wild chimpanzee community. In the experiments, subjects engaged with natural logs, which contained energetically valuable honey that was only accessible through tool use. Engagement with the experiment was highest after periods of low fruit availability involving more travel between food patches, while instances of actual tool-using were significantly influenced by prior travel effort only. Additionally, combining data from the main chimpanzee study communities across Africa supported this result, insofar as groups with larger travel efforts had larger tool repertoires. Travel thus appears to foster tool use in wild chimpanzees and may also have been a driving force in early hominin technological evolution.

Highlights

What evolutionary pressures have favoured tool use in some species, including chimpanzees and humans, but not others? Recent work in non-human primate species has focussed on the role of ecological variables for the emergence of tool use (Fox et al, 1999; Humle and Matsuzawa, 2002; Mobius et al, 2008; Spagnoletti et al, 2012; Sanz and Morgan, 2013)
Our results indicate that travel is directly related to the probability of tool use behaviour in wild chimpanzees
Our data first showed that the combination of low ripe-fruit availability and high travel effort increased their motivation to engage with a foraging problem that required tool use

Summary

Introduction

Recent work in non-human primate species has focussed on the role of ecological variables for the emergence of tool use (Fox et al, 1999; Humle and Matsuzawa, 2002; Mobius et al, 2008; Spagnoletti et al, 2012; Sanz and Morgan, 2013). These studies have enlightened our understanding of how ecology influences animal culture (Whiten et al, 1999; Laland and Janik, 2006) and are informative for modelling early hominin lifestyle (Susman and Hart, 2015). The current literature has generated conflicting and inconclusive results concerning the different ecological hypotheses, even within the same species (chimpanzees (Pan troglodytes verus; necessity: Yamakoshi, 1998; opportunity: Koops et al, 2013; inconclusive: Furuichi et al, 2015); capuchins (Sapajus spp., necessity: Moura and Lee, 2004; opportunity: Spagnoletti et al, 2012); bonobos (Pan paniscus; inconclusive: Furuichi et al, 2015); see (Sanz and Morgan, 2013) for a review)

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