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：毛发显微鉴定是一种无创、简便且经济的方法，广泛应用于哺乳动物物种鉴定的科学研究中。在生态学领域，该方法主要用于哺乳类区系调查与食性研究。近十年来，利用毛发显微鉴定技术开展的食性研究数量大幅增长，但该技术作为捕食者与猎物物种的鉴定工具的应用仍较为匮乏。为此，本研究旨在对新热带区两种最大型食肉动物——美洲豹（Panthera onca Linnaeus, 1758）与美洲狮（Puma concolor Linnaeus, 1771）的粪便样本中的捕食者与猎物毛发进行鉴定。本研究共检视100份粪便样本，其中50份采自南马托格罗索州的潘塔纳尔湿地，另50份采自巴拉那州的大西洋森林。本研究采用了多种鉴定手段，包括毛发的显微与宏观形态鉴定，同时结合粪便中发现的蹄、爪痕迹，以及野外实地调查得到的足迹与猎物残骸信息进行综合判定。在潘塔纳尔湿地的样本中，共鉴定出57个猎物类群；大西洋森林的样本中则鉴定出61个猎物类群。潘塔纳尔湿地样本中有34%检测到了捕食者毛发，大西洋森林样本的这一比例为46%。结合毛发的显微与宏观形态特征，可高效实现不同分类层级的物种鉴定，多数鉴定结果可精确到物种水平。但本研究采用的毛发显微鉴定方法，在完整获取所研究哺乳动物的所有微观结构特征方面仍存在局限。因此需对该技术进行优化调整，以区分同科物种之间的微观结构特征差异。本研究建议，在食性生态学研究中，可通过宏观鉴定粪便内含物（毛发、蹄或爪）的方式，辅助完善毛发显微鉴定技术的应用效果。