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.

The process of forest fragmentation affects mostly top predators, which are more prone to first disappear. Pumas, Puma concolor, are known to have a generalist diet that includes a wide variety of wild and domestic prey species. The capacity of adapting their diet to consuming prey in anthropogenic habitats may be the reason for this species' success in incorporating anthropogenic areas with different levels of fragmentation as part of its habitat. Here we report a case of puma consumption of a large wild prey species, the tapir, Tapirus terrestris. From March 2012 to October 2013 we collected 85 puma's scats opportunistically inside fragments of the Atlantic Forest in the Parana state, Brazil. In one of the scats we found hairs and some hooves of a tapir, as well as puma hairs. We propose two hypotheses that may explain the occurrence of tapir in a pumás scat: (1) an event of scavenging or (2) an event of predation on a juvenile tapir. The most likely explanation for this event may be the predation of a juvenile in response to a possible abundant presence of tapirs in the study area. This event adds to our understanding of the great plasticity of this species to adapt to an altered landscape. To our knowledge, this is the first report of a puma scavenging or predation event on a tapir.

One of the biggest issues in plant ecology is determining the interaction outcome between seeds and scatter-hoarding rodents because the latter has a dual role as dispersers and predators of seeds. Density-dependence contexts involving resource abundance largely influence the outcome of this interaction. Here, we investigated how the variation in the density of a large-seeded tropical tree (Joannesia princeps Vell) affects its probability of seed removal, consumption, dispersal, and burial by a neotropical rodent (Dasyprocta azarae Lichtenstein). We tested whether the elevated resource availability in high tree density areas would cause scatter hoarder’s satiation by decreasing seed removal and consumption (predator satiation hypothesis) or increasing seed dispersal and burial (predator dispersal hypothesis). We tracked the fate of 461 seeds in 14 plots with distinct J. princeps abundances inside a large Atlantic Forest fragment. We used spool-and-line tracking and camera trappings to determine seed fate and identify interacting animals. Agouti was the only species removing J. princeps seeds. Tree density benefitted J. princeps by increasing seed dispersal through buried seed but not affecting seed removal and consumption. This result shows how density-dependent contexts, such as tree density, may alter seed fate in seed–rodent interactions supporting future studies aiming to reestablishing seed dispersal functions in Atlantic Forest fragments.