Muséum national d'histoire naturelle, Département Hommes, Natures, Sociétés UMR 7206 Éco-anthropologie et Ethnobiologie, CP 135, 43 rue Buffon, 75 005 Paris, France.
Physiol Behav. 2012 Jan 18;105(2):337-49. doi: 10.1016/j.physbeh.2011.08.012. Epub 2011 Aug 23.
Certain toxic plants are beneficial for health if small amounts are ingested infrequently and in a specific context of illness. Among our closest living relatives, chimpanzees are found to consume plants with pharmacological properties. Providing insight on the origins of human self-medication, this study investigates the role social systems and physiology (namely gut specialization) play on learning mechanisms involved in the consumption of unusual and potentially bioactive foods by two great ape species. We collected data from a community of 41-44 wild chimpanzees in Uganda (11 months, 2008), and a group of 11-13 wild western gorillas in Central African Republic (10 months, 2008-2009). During feeding, we recorded food consumed, its availability, and social interactions (including observers watching conspecifics and the observers' subsequent activity). Unusual food consumption in chimpanzees was twice higher than in gorillas. Additionally chimpanzees relied more on social information with vertical knowledge transmission on unusual foods by continually acquiring information during their life through mostly observing the fittest (pre-senescent) adults. In contrast, in gorillas observational learning primarily occurred between related immatures, showing instead the importance of horizontal knowledge transmission. As chimpanzees' guts are physiologically less specialized than gorillas (more capable of detoxifying harmful compounds), unusual-food consumption may be more risky for chimpanzees and linked to reasons other than nutrition (like self-medication). Our results show that differences in sociality and physiology between the two species may influence mechanisms that discriminate between plants for nutrition and plants with potential therapeutic dietary components. We conclude that self-medication may have appeared in our ancestors in association with high social tolerance and lack of herbivorous gut specialization.
某些有毒植物如果少量、偶尔摄入且在特定的疾病背景下，对健康是有益的。在我们最亲近的亲属中，黑猩猩被发现会食用具有药理特性的植物。这项研究通过研究社会系统和生理机能（即肠道特化）在两种大型猿类物种食用不同寻常且具有潜在生物活性的食物的学习机制中所扮演的角色，为人类自我医疗的起源提供了深入了解。我们收集了来自乌干达的一个由 41-44 只野生黑猩猩组成的群体（11 个月，2008 年）和一个由 11-13 只野生西部低地大猩猩组成的群体（中非共和国，10 个月，2008-2009 年）的数据。在进食过程中，我们记录了所食用的食物、其可获得性以及社会互动（包括观察同类和观察者随后的活动的观察者）。黑猩猩食用不寻常食物的频率是大猩猩的两倍。此外，黑猩猩更多地依赖于社会信息，通过在其一生中持续获取信息，主要是通过观察最适应环境的（未成年前）成年人，实现了对不寻常食物的垂直知识传递。相比之下，在大猩猩中，观察学习主要发生在相关的未成年个体之间，这表明水平知识传递的重要性。由于黑猩猩的肠道在生理上不如大猩猩特化（更有能力解毒有害化合物），因此不寻常食物的食用对黑猩猩来说可能更具风险，其原因可能不仅是营养，还可能是自我医疗。我们的研究结果表明，这两个物种之间在社会性和生理学方面的差异可能会影响区分营养植物和具有潜在治疗性饮食成分的植物的机制。我们的结论是，自我医疗可能是在我们的祖先中与高社会容忍度和缺乏草食性肠道特化同时出现的。
