Factors Affecting Geographic Variation in Orangutan Diet

猩猩文化的概念具有挑衅性，因为它表明人类文化是在极其复杂的环境背景下进化的。然而，这种复杂性掩盖了环境变化对创新觅食行为起源的潜在影响。本研究的目的是了解导致猩猩饮食地理差异的机制，并确定猩猩的食物选择在多大程度上具有文化基础。要回答的问题可能是，“食物资源的丰富程度和质量的地理差异在多大程度上影响了猩猩的觅食行为和饮食选择？”本文检验了三个主要假设。第一个和第二个假设将决定猩猩是否根据栖息地的营养质量和可用性来选择食物。如果食物选择不能用生态学原理来解释，那么进一步的分析将检验这些食物是否更难加工，是否需要更长的社会学习时间，在幼年的依赖期，猩猩可以持续长达9年。第三个假设将决定猩猩是否会发展出创新的觅食行为来应对食物供应的变化。创新的觅食行为更可能是在食物匮乏时出于需要而进化出来的，还是在食物充足时由于闲暇时间的增加而进化出来的？要使用的基本方法是地理方法。一系列协议整合了印度尼西亚五个实地地点的行为、食物营养分析和食物力学特性的标准化观察：婆罗洲四个研究种群，苏门答腊岛一个研究种群。该项目涉及来自美国、英国、瑞士和印度尼西亚的科学家之间的密切合作。外国科学家和印度尼西亚科学家之间的技术和知识交流对于建立和保护研究伙伴关系及其相关栖息地至关重要。根据人口模型和目前的森林砍伐速度，苏门答腊岛和婆罗洲的猩猩可能在未来25-100年内消失。对猩猩的详细调查和记录促进这种人类近亲创新行为的资源类型至关重要，因为我们将来可能没有机会。了解文化在喂养行为中的重要性对猩猩的保护也很重要。如果社会传播的喂养技能对于维持一个地区的能量预算很重要，那么由于人为干扰，猩猩密度的下降可能导致基本技能传播的机会减少。这可能会导致这些技能从人口中消失。研究结果将为旨在公众教育和保护的纪录片提供信息，这对这种高度濒危物种的持续存在至关重要。这项研究将增加关于哪种食物促进文化创新的知识，并将有助于模拟猿文化起源的环境环境。这一结果对于评估猿与人类之间文化差异的大小以及评估人类为何进化出如此复杂的文化至关重要。

The notion of orangutan culture is provocative, as it suggests that human culture evolved in the context of immense environmental complexity. Yet such complexity obscures the potential effect of environmental variation on the origin of innovative foraging behaviors. The objective of this study is to understand the mechanisms that contribute to geographic variation in orangutan diet, and to establish the degree to which food choice in orangutans has a cultural basis. The question to be answered may be phrased, "To what extent does geographic variation in the abundance and quality of food resources affect orangutan foraging behavior and diet selection?" Three main hypotheses are tested. The first and second hypotheses will determine if orangutans select food items based on nutritional quality and availability in the habitat. If food selection cannot be explained by ecological principles, a further analysis will examine if these foods are harder to process and require longer periods of social learning during the juvenile dependency period, which can last up to nine years in orangutans. The third hypothesis will determine if orangutans develop innovative foraging behaviors in response to variations in food availability. Are innovative foraging behaviors more likely to evolve out of necessity when food is scarce or due to increases in leisure time when food is abundant?The basic methodology to be used is geographical. A series of protocols integrate standardized observations of behavior, food nutritional analyses, and food mechanical properties across five field sites in Indonesia: four study populations in Borneo, and one in Sumatra. This project involves close collaboration between scientists from the United States, England, Switzerland, and Indonesia. Technological and intellectual exchange between foreign and Indonesian scientists is critical to the establishment and conservation of research partnerships and their associated habitats. Based on population models and the current rate of deforestation, orangutans across Sumatra and Borneo may disappear within the next 25-100 years. Detailed investigations on orangutans and documenting the types of resources that promote innovative behaviors in this close human relative are critical because we may not have the opportunity in the future. Understanding the importance of culture in feeding behavior is also important for orangutan conservation. If socially-transmitted feeding skills are important for the maintenance of energy budgets in an area, then a decline in orangutan density, due to anthropogenic disturbances, may result in fewer opportunities for transmission of essential skills. Potentially, this could lead to these skills being lost from the population. The results will inform documentaries aimed at public education and conservation, which is critical for the persistence of this highly endangered species. The research will increase knowledge regarding which kinds of foods prompt cultural innovation and will help model the environmental milieu in which ape culture originated. The results will be critical for assessing the size of the culture gap between apes and humans and for evaluating why humans evolved such cultural complexity.