Ecology, feeding competition, and social relationships of Phayre's leaf monkeys

非人类灵长类动物是所有生物中最具社会性的，在社会组织方面表现出最广泛的变异。因此，对非人灵长类动物的行为和生态学的研究在解决以下问题方面最具影响力：为什么包括人类在内的生物体首先要群居，为什么它们要群居在特定规模的群体中，以及什么因素会影响群体成员之间的社会关系。食叶猴特别有趣，因为它们的生态和社会组织之间的关系与当前的理论并不一致。它们以所谓的大量丰富资源为食，应该生活在大群体中，并表现出弱优势关系。然而，他们往往生活在一个有着强大统治等级的小团体中。该研究正在跟进新的解释性想法，以解决这一争议检查（i）是否间接喂养竞争或杀婴或两者都限制了群体规模的菲尔叶猴（ii）资源分配、觅食竞争和雌性繁殖成功是否符合预测的雌性社会关系和扩散模式。泰国东北部有八种同域灵长类动物，包括两只叶猴（T。cristatus，T. phayrei）和4只猕猴（Macacaarctoides，M. assamensis、M. mulatta、M.线虫属）。研究区域（156，000公顷）未受干扰，包括两种主要生境类型（山地万年青林和干燥万年青林）。从长远来看，这种设置将允许在不同栖息地的灵长类属和相似体型的物种之间进行比较，以及在同一栖息地的相似体型的物种和属之间进行比较。这项研究是在与泰国两所大学（曼谷Kasetsart大学和Mahidol大学）的研究人员以及政府机构（曼谷皇家森林局）官员合作的基础上进行的。每年至少有两名当地工作人员、两名应届毕业生和一名博士后研究人员参加，并提供论文研究机会。这项研究将促进泰国国内和与美国的合作，支持保护区的保护工作，并为学生提供培训和就业机会。

Nonhuman primates are the most social among all organisms and exhibit the broadest range of variation in social organization. Consequently, research on the behavior and ecology of nonhuman primates has been most influential in addressing questions as to why organisms including humans live in groups in the first place, why they live in groups of particular sizes, and what factors influence the social relationships among group members. Leaf-eating monkeys are particularly interesting, because the relationship between their ecology and social organization is not consistent with current theory. Feeding on supposedly large abundant resources, they should live in large groups and exhibit weak dominance relationships. Quite often, however, they live in small groups with strong dominance hierarchies. The study is following up new explanatory ideas to resolve this controversy examining (i) whether indirect feeding competition or infanticide or both constrain group size of Phayre's leaf monkeys (Trachypithecus phayrei) and (ii) whether resource distribution, feeding competition, and female reproductive success conform to the predicted female social relationships and dispersal patterns.Research is conducted at Phu Khieo Wildlife Sanctuary, Northeastern Thailand harboring eight sympatric primates including two leaf monkeys (T. cristatus, T. phayrei) and four macaques (Macaca arctoides, M. assamensis, M. mulatta, M. nemestrina). The study area (156,000 ha) is undisturbed including two major habitat types (hill evergreen and dry evergreen forest). In the long range this setting will allow comparisons within primate genera and species of similar body size across habitats as well as across species and genera of similar body size within the same habitat. The study is based on a collaboration with researchers from two Thai Universities (Kasetsart and Mahidol University, Bangkok) and officials from governmental agencies (Royal Forest Department, Bangkok). Per year it will involve a minimum of two local staff, two recent graduates and one post-doctoral researcher and provide the opportunity for thesis research. The study will foster cooperation within Thailand and with the United States, support conservation efforts in the sanctuary, and provide training and career opportunities for students.