Lévy foraging patterns of rural humans

Movement patterns resembling Lévy walks, often attributed to the execution of an advantageous probabilistic searching strategy, are found in a wide variety of organisms, from cells to human hunter-gatherers. It has been suggested that such movement patterns may be fundamental to how humans interact and experience the world and that they may have arisen early in our genus with the evolution of a hunting and gathering lifestyle. Here we show that Lévy walks are evident in the Me’Phaa of Mexico, in Brazilian Cariri farmers and in Amazonian farmers when gathering firewood, wild fruit and nuts. Around 50% of the search patterns resemble Lévy walks and these are characterized by Lévy exponents close to 1.7. The other search patterns more closely resemble bi-phasic walks. We suggest potential generative mechanisms for the occurrence of these ubiquitous Lévy walks which can be used to guide future studies on human mobility. We show that frequent excursions and meanderings from pre-existing trails can account for our observations.类似列维行走（Lévy walks）的运动模式，常被视作一种优势概率搜索策略的具体表现，广泛存在于从单细胞生物到人类狩猎采集者在内的各类生物体中。有研究指出，此类运动模式或许是人类与世界互动、感知世界的核心基础，且可能早在人属演化出狩猎采集生活方式之初就已出现。本研究证实，列维行走模式可见于墨西哥梅帕（Me’Phaa）族群、巴西卡里里（Cariri）农民，以及亚马逊地区采集柴火、野生果实与坚果的农民群体中。约50%的搜索模式符合列维行走特征，其对应的列维指数（Lévy exponents）接近1.7；其余搜索模式则更趋近于双相行走模式。本研究提出了这类广泛分布的列维行走模式的潜在生成机制，可为未来人类移动性相关研究提供指引；研究表明，频繁偏离既有路径的绕行与漫游即可解释本次观测结果。