Ecologists rely on a wealth of data, including field observations and light stable isotopes, to infer dietary preferences and other ecological and physiological properties in living mammals. But inferring such important traits (e.g., trophic position, metabolism, pathologies) in extinct animals, including humans, can be challenging because biological processes rarely mirror morphology as preserved in the fossil record. For instance, dietary behavior does not necessarily reflect tooth morphology. As an additional challenge, some isotopic mammal tissues commonly used in modern ecology, such as collagen in bone or dentin or keratin from hair, hoof, or horn, do not generally preserve in fossil remains older than ∼200 kyr. In contrast, major constituents of bioapatite often retain their initial isotopic composition through fossilization processes. Recent analytical developments in mass spectrometry now allow, using small samples, for assessment of isotopic variability of major and trace elements such as calcium or zinc. Here, we review the application potentials of metal (nontraditional isotopes) for (paleo)ecological, (paleo)physiological, and (paleo)mobility inferences as applied to mammalian research. ▪ Mammals are key elements of modern ecosystems and possess a rich evolutionary history, yet inferences about their past ecologies and physiologies are challenging to retrieve using traditional geochemical toolkits. ▪ Metal stable isotopes provide a novel and complementary approach to unveil paleoecological and paleophysiological characteristics of extinct mammal species. ▪ Within a 20-year time frame, the core of metal isotopic data in mammalian research remains small compared to traditional isotopic systems (C, O, N), which is inviting for designing cost-effective instrumentation and increasing dissemination across scientific disciplines.

中文翻译：

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哺乳动物组织中的金属同位素


生态学家依靠大量数据，包括实地观察和光稳定同位素，来推断现存哺乳动物的饮食偏好和其他生态和生理特性。但是，推断已灭绝动物（包括人类）的如此重要特征（例如，营养位置、新陈代谢、病理学）可能具有挑战性，因为生物过程很少反映化石记录中保存的形态。例如，饮食行为不一定反映牙齿形态。作为另一个挑战，现代生态学中常用的一些同位素哺乳动物组织，例如骨骼或牙本质中的胶原蛋白或头发、蹄或角中的角蛋白，通常不会保存在超过 200 kyr 的化石遗骸中。相比之下，生物磷灰石的主要成分通常通过化石过程保留其初始同位素组成。质谱分析的最新发展现在允许使用小样品来评估主量和痕量元素（如钙或锌）的同位素变异性。在这里，我们回顾了金属（非传统同位素）在（古）生态学、（古）生理学和（古）迁移性推断中的应用潜力，这些推断应用于哺乳动物研究。▪ 哺乳动物是现代生态系统的关键要素，拥有丰富的进化历史，但使用传统的地球化学工具包很难检索关于它们过去的生态学和生理学的推断。▪ 金属稳定同位素提供了一种新颖的互补方法来揭示已灭绝哺乳动物物种的古生态和古生理特征。 ▪ 在 20 年的时间框架内，与传统同位素系统（C、O、N）相比，哺乳动物研究中金属同位素数据的核心仍然很小，这对于设计具有成本效益的仪器和增加跨学科的传播很有吸引力。