黄山短尾猴食土行为

从行为生态学角度,依据黄山短尾猴食土行为在年龄、性别、社会等级序位、食土量、食土频率、食土持续时间中的分布和变化规律,结合土壤基本理化性质测定和分析,探讨了黄山短尾猴食土行为。黄山短尾猴对土壤的摄取是寻找和有目的的选择,有些场所是其"喜好"或"常去之处",食土场所通常是以多个体多次取食挖掘而形成的洞穴形式存在。取食土壤颜色黄色或黄棕色,酸性土壤,富含铁、钙、镁等矿物元素,粘土比例较高。社群各年龄段及性别个体均参与食土行为。平均食土行为持续时间在年龄和性别之间无显著差异;平均食土频率和食土量在成年雌性或雄性个体的社会等级序位之间无显著性差异;而成年雌性的平均食土频率和食土量,显著高于其它年龄或性别组,与雌性正值怀孕末期及产仔哺乳期,需要补充大量铁等矿物元素,以维持生理所需和体力消耗有关。典型的植食性动物黄山短尾猴有规律地取食粘土的行为,支持了食土行为具有"食物解毒作用"假说。人工投喂和食土行为的相关性表现为提高了食土频率,可能与粘土能够缓解高热量、低纤维人工食物造成的胃肠不适有关。

Geophagy of Macaca Thibetana at Mt. Huangshan, China

Geophagy, or soil ingestion, is the deliberate act of eating soil. This behavior is a widespread practice in the animal world, particularly among generalist herbivores and primates. Primates consume a wide and complex variety of food items that vary temporally and spatially. Mature leaves, flowers, leaf buds, fruits, seeds and invertebrates constitute the bulk of potential food items. The close link between geophagy and primates suggests a need to ingest soil. Various nonexclusive principal functions have been advanced to explain geophagic behaviors, the main ones being: taste enhancement, detoxification of noxious or unpalatable compounds present in plant foods, supplementation of mineral nutrients, alleviation of gastrointestinal upsets such as diarrhea, counteraction of the effects of endoparasites and reduction of excess acidity in the digestive tract. So far no studies on the possible adaptive significance and ecological consequences of geophagy in primates have been published in China. In this paper we report 207 incidences of geophagy observed among provisioned Thibetana macaques (Macaca thibetana) at Mt. Huangshan, China. The group consisted of 19 animals that were routinely provisioned (four times a day) with cereal corn that supplemented their natural food sources. We gathered data on the identities, ages and sexes of participants as well as the frequency, amounts, duration of geophagy. Soil samples (uneaten and eaten) were analysed for the following chemical and physical properties: soil color, pH, water content, mineral elements. The purpose of the study is to describe the behavior of geophagy and its implications for provisioned species. The results show that soil is sought and purposefully selected, and that some sites are preferred and have been mined by many individuals for a long time. Soils that the monkeys choose are yellow or yellow-brown, weakly acid, with an abundant amount of clay, and are richer in certain mineral elements, especially iron, calcium and magnesium than uneaten soil. Organic-rich soil appears not to be eaten by the monkeys engaging in geophagy. All age groups and both sexes consume soil, but adults as a group are more inclined to geophagy than the other age groups. Mean duration of geophagy does not differ significantly with age or sex. Mean frequencies and amounts of geophagy do not differ significantly by social rank for either males or females. Adult females are the most frequent consumers of soil. Mineral supplementation during pregnancy and lactation may be important as a stimulus to geophagy behavior of adult females. This study supports the food detoxification hypothesis that the soils consumed regularly by Tibetan macaques feeding on a variety of plant species help to absorb the toxic constituents therein. Monkeys showed a decided preference for geophagy especially when they were heavily provisioned. It is possible that Tibetan macaques ingest clay to alleviate gastric upsets made by high energy, low fiber human foods. Tibetan macaques may indulge in geophagy for one or a combination of reasons. Therefore future research requires interdisciplinary efforts among soil, plant and animal sciences, focusing on the roles of geophagy vis a vis primate nutrient requirements, parasitology, feeding ecology, phytochemistry, soil microbiology, mineralogy of soil, and effects on the bioactivity of consumed plants.