Farassi Rassina, d'Oliveira Coelho João, Carvalho Susana
Fundació UdG: Innovació i Formació, Universitat de Girona, Girona, Spain.
Centre for Functional Ecology, Universidade de Coimbra, Coimbra, Portugal.
Am J Biol Anthropol. 2025 Jul;187(3):e70094. doi: 10.1002/ajpa.70094.
Studying object manipulation may offer insights about the emergence of habitual tool use in the hominin clade. Previous research on object manipulation has focused on habitual tool-using animals such as apes, capuchins, dolphins, and corvids. Investigating object manipulation in wild baboons, a highly social, ecologically adaptable, and terrestrial primate that is not a habitual tool user, can shed further light on the pressures favoring or inhibiting the use of technology. In this study, we investigate factors that influence object manipulation in the chacma baboons of Gorongosa National Park, across demographic and environmental conditions.
We collected data using focal and scan sampling, with the aid of the Animal Observer app, and recorded object use and other behaviors. We followed three focal troops: Chitengo, Montebelo, and Floodplain. A total of 2262 observations were recorded across 88 individuals (787 events involved object use).
Mixed-effects logistic regressions revealed that habitat, age, and substrate use significantly predicted object use among baboons. Object use was most likely in open forests. Adults are less likely to engage in object manipulation, and this behavior decreases with age, which is in line with previous results reported for bonobos. Interestingly, baboons spend more time manipulating objects arboreally than terrestrially.
Our findings contribute to the current discussions about the contexts that promote tool use across the primate order. Further studies expanding on these results and assessing differential availability of resources can provide a more comprehensive understanding of the evolution of tool use.
研究物体操控可能有助于深入了解人类进化支中习惯性工具使用的出现。此前关于物体操控的研究主要集中在习惯性使用工具的动物身上，如猿类、卷尾猴、海豚和鸦科动物。研究野生狒狒的物体操控行为，这种高度社会化、生态适应性强的陆生灵长类动物并非习惯性工具使用者，能够进一步揭示有利于或抑制技术使用的压力因素。在本研究中，我们调查了影响戈龙戈萨国家公园 chacma 狒狒在不同人口统计学和环境条件下物体操控的因素。
我们借助 Animal Observer 应用程序，采用焦点取样和扫描取样的方法收集数据，并记录物体使用及其他行为。我们跟踪了三支焦点群体：奇滕戈、蒙特贝洛和平原群体。共对 88 只个体进行了 2262 次观察记录（其中 787 次事件涉及物体使用）。
混合效应逻辑回归分析表明，栖息地、年龄和底物使用显著预测了狒狒的物体使用情况。在开阔森林中，物体使用最为常见。成年狒狒进行物体操控的可能性较小，且这种行为随年龄增长而减少，这与此前关于倭黑猩猩的研究结果一致。有趣的是，狒狒在树上操控物体的时间比在地面上更多。
我们的研究结果有助于当前关于促进整个灵长目动物使用工具的背景的讨论。进一步拓展这些结果并评估资源差异可用性的研究，能够更全面地理解工具使用的进化过程。
