Doctoral Dissertation Improvement: The Juvenile Balancing Act: Survival, Skill-learning, and Growth in Phayre's Leaf Monkeys

灵长类动物的特点是幼年期异常长，从而产生延迟繁殖的成本。这种延长的发育过程在人类中最为明显，这与培养大型大脑的高成本有关。其他研究人员假设，长期的青少年是对学习复杂的生态或社会技能的必要性的反应，或者是青少年风险厌恶的结果。从这一理论的角度来看，拟议的研究旨在回答四个主要问题：（一）青少年使用他们的时间来获得生态技能，（二）他们使用空间策略，以减少风险，（三）如何做社会关系提供的好处，（四）增长率反映青少年技能获取的变化。研究将在泰国东北部的Phu Khieo野生动物保护区进行，对22只幼年Phayre叶猴（Trachythecus phayrei）进行为期20个月的跟踪。除了食物的机械特性和营养成分外，还将收集喂养和社会数据。生长率将评估非侵入性使用摄影测量方法来测量limblength.The拟议的研究的智力价值是其新的角度的作用，技能获取。食物机械特性在觅食个体发育中的作用很少被详细研究。这项研究还通过整合行为和生长指标迈出了重要一步，这些因素在非人类灵长类动物研究中很少同时考虑。总的来说，大多数灵长类动物的研究都集中在成年受试者身上，因此忽略了在成年之前可能存在的不同的选择压力。该项目提供了一个机会，以增加急需的数据，任何讨论有关延长幼年灵长类动物之间的假设。在更广泛的影响方面，这项研究将是第一个利用非侵入性方法测量野生灵长类动物的生长。大多数灵长类动物的生长数据只能从不受自然环境资源短缺的圈养动物中获得。为在实地研究中更实际和更经常地使用这些非侵入性方法铺平道路，特别是对于树栖物种，将提高我们对生长和发育以及与行为的相互关系的理解。这项研究也将成为博士学位的基础。包括当地的助手。通过这种参与，该项目将帮助保护区工作人员获得行为数据收集和植物采样的各个方面的经验。共同PI将积极协助PI为泰国学生开设保护和实地方法课程。与当地学生，科学家和保护区工作人员分享想法将有助于确保长期致力于研究和保护这个拥有非凡生物多样性的地点，包括8种灵长类动物。

Primates are characterized by an unusually long juvenile period generating costs in terms of delayed reproduction. Such a lengthened development, most distinct among humans, has been linked to high costs of growing large brains. Other researchers hypothesize that long juvenility is a response to the necessity of learning complex ecological or social skills or a consequence of juvenile risk aversion. Drawing from this theoretical perspective the proposed study aims at answering four main questions: (i) do juveniles use their time to acquire ecological skills, (ii) do they use spatial tactics to reduce risks, (iii) how do social relationships provide benefits, (iv) do growth rates reflect variation in juvenile skill acquisition. Research will be conducted at Phu Khieo Wildlife Sanctuary, Northeastern Thailand, following 22 juvenile Phayre's leaf monkeys (Trachypithecus phayrei) over a period of 20 months. Feeding and social data will be collected in addition to mechanical properties and nutrient content of food. Growth rates will be assessed non-invasively using photogrammetric methods to measure limb length.The intellectual merit of the proposed research is its new perspective on the role of skill acquisition. The role of food mechanical properties in foraging ontogeny has rarely been investigated in detail. This study also takes an important step by integrating behavioral and growth measures, factors rarely considered simultaneously in studies of nonhuman primates. Overall, most primate research has focused on adult subjects, thus neglecting the potentially different selective pressures operating well before adulthood. This project provides an opportunity to add much-needed data to any discussion concerning hypotheses for extended juvenility among primates.In terms of broader impacts this study will be one of the first to utilize non-invasive methods for measuring growth in wild primates. Most primate growth data are available only from captive animals not subject to resource shortages of natural environments. Paving the way for more practical and regular use of these non-invasive methods in field studies, particularly for arboreal species, will improve our understanding of growth and development and the interrelationship with behavior. The study will also form the basis for a Ph.D. involving local assistants. Through this involvement the project will help sanctuary workers to gain experience with all aspects of behavioral data collection and plant sampling. The co-PI will be an active assistant in a conservation and field methods course for Thai students, which will be conducted by the PI. Sharing ideas with local students, scientists and sanctuary workers will help to ensure a long-term commitment to both research and conservation at this site of extraordinary biodiversity including 8 primate species.