Doctoral Dissertation Research: Weaned Age Variation and Trace Element Distributions in Primate Teeth

对于我们的人类祖先来说，断奶年龄的转变可能有助于更高的繁殖成功率和人口增长。然而，这种适应性转变的进化背景并没有得到充分的理解，部分原因是在从化石记录中获得断奶证据的方法上的限制。这个博士论文项目将分析野生山地大猩猩牙齿中保存的化学特征，以确定这些特征如何与断奶和社会生态因素相关。该项目的发现可以作为将这种方法应用于人类化石记录的基础。 该项目将包括对学生的科学培训和指导，包括来自STEM领域代表性不足的群体的个人。 它还将加强研究合作，支持公共科学宣传和教育，并为正在进行的灵长类动物保护工作提供信息。 研究人员将测试一种正在开发的方法，用于从牙齿中钙标准化锶和钡强度的分布重建早期生活饮食过渡的时间，并调查来自卢旺达火山国家公园的维龙加山地大猩猩的单一记录良好的野生种群内的断奶年龄变化。山地大猩猩的食物资源的化学签名的特点，以提供一个解释变化的背景下，在牙釉质和牙本质钡和锶的强度。估计断奶年龄的微量元素分析，然后将野生山地大猩猩饮食和哺乳的纵向记录进行比较。将解决以下问题：1）牙齿中的微量元素分布与哺乳的行为观察和用于确定断奶年龄的其他指标（例如，出生间隔）？2）在野生山地大猩猩种群中，断奶的化学特征是如何变化的？合作伙伴的能力，从个人在这个人口的行为和化学数据代表了一个独特的机会，以测试一个新兴的方法，恢复相对高分辨率的证据断奶在人类化石record.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

For our human ancestors, a shift toward earlier age at weaning may have contributed to higher reproductive success and population growth. However, the evolutionary context of this adaptive shift is not fully understood, in part because of methodological constraints in obtaining evidence of weaning from the fossil record. This doctoral dissertation project will analyze chemical signatures preserved in the teeth of wild mountain gorillas to determine how those signatures may be related to weaning and socioecological factors. Findings from this project could then serve as a foundation for applying this approach to the human fossil record. This project will include scientific training and mentorship of students, including individuals from groups underrepresented in STEM fields. It will also bolster research collaborations, support public science outreach and education, and inform ongoing primate conservation efforts. The investigators will test a developing method for reconstructing the timing of early-life dietary transitions from the distribution of calcium-normalized strontium and barium intensities in teeth, and to investigate weaning age variation within a single well-documented wild population of Virunga mountain gorillas from Volcanoes National Park in Rwanda. The chemical signature of mountain gorilla food resources will be characterized in order to provide a context for interpreting variation in enamel and dentine barium and strontium intensities. Estimated weaned age from trace element analysis will then be compared to longitudinal records on wild mountain gorilla diet and suckling. The following questions will be addressed: 1) How well do trace element distributions in teeth correspond to behavioral observations of suckling and other metrics for determining weaning age (e.g., interbirth interval)? and 2) How does the weaning chemical signature vary within a wild mountain gorilla population? The ability to partner behavioral and chemical data from individuals in this population represents a unique opportunity to test an emerging methodology for recovering relatively high resolution evidence of weaning in the human fossil record.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.