Geophagy is the intentional consumption of soil and has been observed in various animal taxa including human and nonhuman primates. Among the numerous adaptive hypotheses proposed to explain this behavior, two of them stand out: soil either protects the gastrointestinal tract from secondary plant compounds, parasites and pathogens, and/or supplements micronutrients in the diet. Few studies have characterized the physical and chemical characteristics of soils consumed by nonhuman primates. Here, we describe the composition of soils consumed by yellow-tailed woolly monkeys (Lagothrix flavicauda) in comparison with soils taken from surrounding areas. We also studied the physical aspects of geophagy sites in terms of accessibility, dimensions and vegetation density. This study took place at the La Esperanza field site, in northern Peru, between 2016 and 2018. We conducted focal follows, placed camera traps at geophagy sites and sampled soils. In total, we recorded 77 geophagy events. Our results highlight some aspects of soil and site selection in these arboreal primates, who face an increased predation risk when descending to the ground. Animals preferred smaller sites with denser surrounding vegetation. Composition of consumed soils was similar between geophagy sites. Soils were poor in micronutrients, but contained around 20% clay. High clay content, coupled with the fact that geophagy was performed significantly more in the dry season, when leaf consumption is highest, lends support to geophagy as a mechanism for protection of the gastrointestinal tract in L. flavicauda.

中文翻译：

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秘鲁拉埃斯佩兰萨黄尾毛猴（Lagothrix flavicauda）的食土：场地特征和土壤成分

Geophagy 是对土壤的有意消耗，已在各种动物分类群中观察到，包括人类和非人类灵长类动物。在为解释这种行为而提出的众多适应性假设中，其中两个脱颖而出：土壤保护胃肠道免受次生植物化合物、寄生虫和病原体的侵害，和/或补充饮食中的微量营养素。很少有研究描述非人类灵长类动物消耗的土壤的物理和化学特性。在这里，我们描述了黄尾毛猴（Lagothrix flavicauda）消耗的土壤成分与从周边地区采集的土壤的比较。我们还从可及性、尺寸和植被密度方面研究了食土站点的物理方面。这项研究在秘鲁北部的 La Esperanza 现场进行，在 2016 年至 2018 年之间。我们进行了焦点跟踪，在自噬地点放置了相机陷阱并采样了土壤。我们总共记录了 77 个 geophagy 事件。我们的研究结果突出了这些树栖灵长类动物的土壤和地点选择的某些方面，它们在下降到地面时面临增加的捕食风险。动物更喜欢周围植被密集的较小地点。吞噬地点之间消耗的土壤组成相似。土壤的微量营养素含量很低，但含有约 20% 的粘土。高粘土含量，再加上在旱季进行的食土显着更多，此时叶消耗量最高，支持将食土作为保护黄尾鱼胃肠道的机制。我们记录了 77 个 geophagy 事件。我们的研究结果突出了这些树栖灵长类动物的土壤和地点选择的某些方面，它们在下降到地面时面临增加的捕食风险。动物更喜欢周围植被密集的较小地点。吞噬地点之间消耗的土壤组成相似。土壤的微量营养素含量很低，但含有约 20% 的粘土。高粘土含量，再加上在旱季进行的食土显着更多，此时叶消耗量最高，支持将食土作为保护黄尾鱼胃肠道的机制。我们记录了 77 个 geophagy 事件。我们的研究结果突出了这些树栖灵长类动物的土壤和地点选择的某些方面，它们在下降到地面时面临增加的捕食风险。动物更喜欢周围植被密集的较小地点。吞噬地点之间消耗的土壤组成相似。土壤的微量营养素含量很低，但含有约 20% 的粘土。高粘土含量，再加上在旱季进行的食土显着更多，此时叶消耗量最高，支持将食土作为保护黄尾鱼胃肠道的机制。动物更喜欢周围植被密集的较小地点。吞噬地点之间消耗的土壤组成相似。土壤的微量营养素含量很低，但含有约 20% 的粘土。高粘土含量，再加上在旱季进行的食土显着更多，此时叶消耗量最高，支持将食土作为保护黄尾鱼胃肠道的机制。动物更喜欢周围植被密集的较小地点。吞噬地点之间消耗的土壤组成相似。土壤的微量营养素含量很低，但含有约 20% 的粘土。高粘土含量，再加上在旱季进行的食土显着更多，此时叶消耗量最高，支持将食土作为保护黄尾鱼胃肠道的机制。