Collaborative research: Social conventions, sexual selection, and acoustic signals in wild brown capuchins

结合物体并将物体用作工具的能力被认为是我们物种和人物的主要成就之一，深深植根于我们对人类智力和行为进化的神话、哲学、文化和学术解释中。许多研究人员认为，物体操纵、语言、社交技能和大脑结构在人类进化过程中是相互关联的。在过去的40年里，卷尾猴，一种属于Cebus属的新大陆灵长类动物，经常被认为是人类智力和工具使用进化的模型。在灵长类动物中，只有黑猩猩和人类在组合和操纵物体的频率和复杂性方面超过卷尾猴。虽然提示性的观察来自圈养的卷尾猴，但几乎没有来自野生种群的证据来检验为什么在自然环境中特殊的操纵能力会有利以及个体如何获得这些技能的假说。苏里南中部自然保护区(CSNR)的棕色卷尾猴(Cebus Apella)使用复杂物体操作的比率是迄今为止野生卷尾猴中最高的。更具体地说，CSNR的雄性卷尾猴使用一系列被标记为敲击的物体组合和手法：将棍子或坚硬的水果敲打在坚硬的表面上，并折断树枝。与基于视觉显示的社会信号相比，敲击产生的机械(非发声)声学声音在这种茂密的森林环境中传播得更远、更可靠。初步观察表明，卷尾猴评估雄性敲击时发出的噪音的声学结构，作为雄性力量和活力的真实指标，这在雄性配偶竞争和雌性配偶选择中很重要，即雄性敲击越强烈，噪音越大。这项研究项目评估了关于(1)棕色卷尾猴敲击行为的功能，重点是在性选择和觅食中积累的相对利益，以及(2)敲击行为的表达与个体的发展状况和社会环境之间的关系的假说。无论发现什么，其理论意义都是重要的，涵盖了人类学、生物学、生态学和心理学。在CSNR，打击行为将在卷尾猴社会独特的生态背景下得到最充分的理解。首先，与其他新热带地区相比，贵南高原的生物群具有极低的能量和营养流动的特点。其次，这些区域生态特征由于哥伦比亚前美洲印第安人在现在被CSNR覆盖的地区进行的以前意想不到的景观土方工程而变得更加复杂。Boinski及其同事最近的探索工作证实，CSNR存在普遍的考古特征；这些地点与卷尾猴优先使用的竹子和藤本植物森林栖息地相同。这个灵长类和群落生态学研究项目自1998年以来一直在苏里南自然资源中心进行，并且是自暴力内乱(1970年末S-1990年初S)结束以来苏里南林区内唯一的多年生态项目。Boinski和她的团队与苏里南的生物学家、教育工作者、野生动物和保护官员、国际非政府组织和和平队合作。苏里南公园管理局和研究小组之间发展了长期的支持关系，导致教育和保护宣传，以及该项目对苏里南科学基础设施的贡献，远远超出了直接的研究产品。从研究录像带制作的教育视频将在网上免费提供。在国家和外国利益寻求扩大对这些森林的经济开发的历史时刻，CSNR项目正在向苏里南人提出关于他们无与伦比的森林的文化和生物意义的挑衅性问题。

The capacity to combine objects and employ objects as tools is considered one of the major achievements of our species and figures deeply in our mythological, philosophical, cultural, and academic explanations for the evolution of human intelligence and behavior. Many researchers hold that object manipulation, language, social skills, and brain structure are been linked in human evolution. For the past 40 years capuchins monkeys, New World primates in the genus Cebus, have often been suggested as models for the evolution of intelligence and tool use in humans. Among primates, only only chimpanzees and humans exceed capuchins in the frequency, complexity with which objects are combined and manipulated. Although suggestive observations come from capuchins in captivity, scant evidence from wild populations is available to test hypotheses as to why exceptional manipulative abilities can be advantageous in natural settings and how individuals acquire these skills. Brown capuchins (Cebus apella) in the Central Suriname Nature Reserve (CSNR) use complex object manipulation at the highest rates yet documented among wild capuchins. More specifically, male capuchins at CSNR employ an array of object combinations and manipulations labeled as percussion: striking sticks or hard fruit against hard surfaces and breaking off tree limbs. Percussion generates mechanical (non-vocal) acoustic sounds that transmit farther and more reliably in this densely forested environment than social signals based on visual displays. Preliminary observations suggest that capuchins evaluate the acoustic structure of the noises males produce in percussion as honest indicators of male strength and vigor important in male-mate competition and female mate choice, i.e., the stronger the male percussing, the louder the noise. This research project evaluates hypotheses about (1) the functions of brown capuchins' percussive behavior, focusing on the relative benefits accruing in sexual selection versus foraging, and (2) the expression of percussion in relation to an individual's developmental status and social circumstances. Whatever the findings, the theoretical implications are important and encompass anthropology, biology, ecology, and psychology. Percussive behavior will be most fully understood against the distinctive ecological background of capuchin society at CSNR. First, the biota of the Guianan Plateau is characterized by extremely low energy and nutrient flow relative to other Neotropical regions. Second, these regional ecological characteristics are compounded by previously unsuspected landscape earthworks by pre-Columbian Amerindians populations in the area now encompassed by the CSNR. Recent exploratory work by Boinski and colleagues confirms that pervasive archeological features are present in CSNR; these sites covary with the bamboo and liana forest habitats preferentially used by capuchins. This primate and community ecology research program has been ongoing in the CSNR since 1998 and remains the only multi-year ecological project within Suriname's forested interior since the end of violent civil uprisings (late 1970's - early 1990's). Boinski and her team work with biologists, educators, and wildlife and conservation officials of Suriname, international NGOs, and Peace Corps. Long-term supportive relations have developed between Surinamese Park Service and the research team, leading to educational and conservation outreach and contributions to the scientific infrastructure of Suriname by this project far beyond the immediate research products. Educational videos produced from research tapes will be made freely available on the web. The CSNR project is engaging the Surinamese with provocative questions about the cultural and biological significance of their matchless forests at a moment in history when national and foreign interests seek to expand economic exploitation of these same forests.