Hair as a tool for identification of predators and prey: a study based on scats of jaguars (Panthera onca) and pumas (Puma concolor)

Abstract: Microscopic hair identification is a non-invasive, simple, and economical method applied in scientific studies to identify mammal species. In ecology, this method is used mainly in mastofaunistic inventories and dietary studies. In the last decade, the number of dietary studies using the microscopic identification of hairs has grown substantially, but the application of this technique as a tool for the identification of both predators and prey species is still scant. Thus, the aim of this study was to identify predator and prey hairs in scat samples from the two largest species of carnivores in the Neotropical region, the jaguar (Panthera onca Linnaeus, 1758) and the puma (Puma concolor Linnaeus, 1771). We examined a total of 100 scat samples being 50 from the Pantanal of Mato Grosso do Sul and 50 from the Atlantic Forest of Paraná. We used different identification categories that included the hair microscopic and macroscopic identification, as well as the use of hooves and nails present in the scats associated with tracks and kills found in the field. We identified 57 prey items in the Pantanal samples and 61 in the Atlantic Forest samples. Predator´s hairs were identified in 34% of Pantanal samples and in 46% of Atlantic Forest samples. The combination of hair microscopic and macroscopic characteristics was efficient in the identification of different taxonomic levels, with most identifications reaching the level of the species. However, the methodological protocol for microscopic hair identification was not fully effective in obtaining all the microstructural patterns of the studied mammals. Adjustments in the technique are necessary to differentiate microstructural characteristics of species belonging to the same family. We recommend macroscopic identification of scat content items (hairs, hooves or nails) of both prey and predators to be used to complete the microscopic hair identification technique in dietary ecological studies.

摘要：毛发微观鉴定（microscopic hair identification）是一种非侵入式、简便且经济的方法，被应用于科学研究中以鉴别哺乳动物物种。在生态学领域，该方法主要用于大型哺乳动物区系调查（mastofaunistic inventories）和食性研究（dietary studies）。近十年来，利用毛发微观鉴定开展的食性研究数量大幅增长，但将该技术同时用于鉴定捕食者与猎物物种的应用仍较为匮乏。因此，本研究旨在对新热带区（Neotropical region）两种最大型食肉动物——美洲豹（Panthera onca Linnaeus, 1758）和美洲狮（Puma concolor Linnaeus, 1771）的粪便样本（scat samples）中的捕食者与猎物毛发进行鉴定。我们共检测了100份粪样，其中50份来自南马托格罗索州的潘塔纳尔湿地（Pantanal），另外50份来自巴拉那州的大西洋森林（Atlantic Forest）。我们采用了多种鉴定类别，涵盖毛发的微观与宏观形态鉴定，同时结合了粪便中发现的蹄、爪，以及野外发现的足迹与猎杀痕迹进行辅助鉴定。在潘塔纳尔湿地的样本中鉴定出57个猎物类群，大西洋森林样本中则鉴定出61个。在34%的潘塔纳尔样本和46%的大西洋森林样本中，成功鉴定出了捕食者的毛发。结合毛发的微观与宏观形态特征，可高效实现不同分类阶元（taxonomic levels）的鉴定，多数鉴定可精确到物种水平。然而，现有毛发微观鉴定的方法学规程（methodological protocol）无法完全获取所研究哺乳动物的全部微观结构特征。需对该技术进行优化调整，以区分同科物种间的微观结构差异。我们建议在食性生态学研究中，将猎物与捕食者的粪便内容物（毛发、蹄或爪）的宏观鉴定作为补充，与毛发微观鉴定技术结合使用，以完善鉴定流程。