Collaborative Research: Hard Tissue evidence of weaning variation in primates

断奶(停止母乳喂养)是一个重要的发展里程碑，对产妇生殖战略和婴儿结局具有重要影响。现代人类平均比类人猿更早地断奶，但这种独特的人类模式的进化起源还没有被很好地理解。这个跨学科的研究项目将研究三个不同野生类人猿物种的行为、生态、生理和发育数据，以了解在比较灵长类动物框架下断奶变异的来源。该项目将使用可翻译为古生物学背景的方法，更全面地了解我们最亲近的亲属断奶变异的生物学、生态学和社会相关性，从而有助于建立一个了解人类断奶进化的框架。该项目将通过有组织的实习、指导和为学生和早期职业科学家提供其他增强的培训机会，扩大未被充分代表的群体在科学领域的参与。通过建立与灵长类保护和人类进化生物学交叉的许多问题相关的新的合作和跨学科数据集，研究基础设施将得到加强。这项工作的结果将促进我们对这些极度濒危的类人猿的种群动态和健康的了解，并将被传达给野生动物兽医和公园管理人员，以告知保护策略，以及通过在线和其他公共场所。断奶的时间代表了母体和后代进化利益的平衡，对生理限制以及物理和社会环境都很敏感。然而，对现存灵长类动物的行为观察不能区分护理的营养和社会功能，在古生物背景下重建断奶的方法在区分密切相关类群之间的断奶变异方面存在局限性。这项对野生大猩猩断奶变异的比较和多代理研究集中在三个生态上不同的种群，它们在哺乳行为和母体繁殖策略方面表现出显著的差异：在生态上有显著差异的维龙加和布温迪山地大猩猩，以及提供了重要分类学对比的冈贝黑猩猩。该项目结合了从生命中的个体收集的哺乳和喂养行为、身体发育和粪便稳定同位素数据，以及他们食物的化学特征，以及这些群体死后相关骨骼的形态和牙齿微量元素分析。这项研究调查了(1)哪些因素影响了现存野生黑猩猩和大猩猩断奶相关的饮食转变的可变性，(2)生物组织(粪便、牙齿)中的化学替代品如何与断奶的行为和解剖代用品相关，以及(3)牙齿微量元素在个人和种群水平上记录饮食历史的可变性的可靠性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Weaning (cessation of breastfeeding) is a critical developmental milestone with important consequences for maternal reproductive strategies and infant outcomes. Modern humans wean their young much earlier on average than the great apes, but the evolutionary origins of this uniquely human pattern are not well understood. This interdisciplinary research project will study behavioral, ecological, physiological, and developmental data for three different wild great ape species, to understand sources of weaning variation in a comparative primate framework. The project will generate a more comprehensive understanding of the biological, ecological and social correlates of weaning variation in our closest living relatives using approaches that are translatable to paleontological contexts, thus contributing to a framework for understanding the evolution of weaning in humans. This project will broaden participation of underrepresented groups in science through structured internships, mentoring and other enhanced training opportunities for students and early career scientists. Research infrastructure will be enhanced by establishing new collaborations and interdisciplinary datasets relevant to many questions at the intersection of primate conservation and human evolutionary biology. Results of this work will advance our understanding of the population dynamics and health of these critically endangered apes, and will be communicated to wildlife veterinarians and park managers to inform conservation strategies, as well as through online and other public venues.The timing of weaning represents a balance of maternal and offspring evolutionary interests, and is sensitive to physiological constraints as well as physical and social environments. However, behavioral observations of living primates cannot distinguish nutritive versus social functions of nursing, and methods for reconstructing weaning in paleontological contexts are limited in their ability to discriminate weaning variation among closely-related taxa. This comparative and multi-proxy study of weaning variation in wild great apes focuses on three ecologically-distinct populations that show pronounced variation in suckling behavior and maternal reproductive strategies: Virunga and Bwindi mountain gorillas, which differ markedly in ecology, and Gombe chimpanzees, which provide an important taxonomic contrast. This project integrates suckling and feeding behavior, physical development, and fecal stable isotope data collected from individuals in life, with chemical characterization of their foods, and morphological and dental trace element analyses of associated skeletons from these populations after death. This research investigates (1) what factors influence variability in weaning-related dietary transitions across living wild chimpanzees and gorillas, (2) how chemical proxies in biological tissues (fecal, dental) relate to behavioral and anatomical proxies of weaning, and (3) how reliably dental trace elements record variability in documented dietary histories at the individual and population levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.