The giant anteater Myrmecophaga tridactyla is categorized as Vulnerable on the IUCN Red List, and is extinct in several locations as a result of environmental pressures. We present the first records of the giant anteater in the largest continuous expanse of the Atlantic Forest biome, in southern Brazil, highlighting its occurrence in the highlands of the Serra do Mar mountain range. During a camera-trapping survey of medium and large mammals we obtained two records of the species, one in 2013 and the other in 2014. These records from dense rainforest highlands indicate the importance of this environment for the giant anteater and highlight these areas as possible foci for future studies of the species. In addition, we present a review of the species’ occurrence in protected areas in Brazil, to provide a resource for the conservation of this species and for future re-evaluations.

Interactions between predators and prey affect their distributions and abundances, and these effects are of central importance in ecology. However, these interactions are difficult to observe in some free-ranging species due to their elusive behaviour. We describe the video-recorded observation of predation of a grey brocket deer (Mazama gouazoubira) by a tayra (Eira barbara), which is the largest prey reported for this mustelid. Additionally, we report three other wild species (Dasypus sp., Sylvilagus brasiliensis and Leontopithecus chrysopygus) predated by tayra and we present a review of tayra attacks on, and predation of, small primates and other medium and large-sized mammal prey. Surprisingly, this mustelid is capable of predating a high diversity of species, both arboreal and terrestrial. At least 20 species were seen to be predated or attacked by tayras, which are capable of predating species with up to twice its own body weight, information which may be unknown due to its elusive behaviour. Additionally, we discuss the role of tayra in a community structure and raised the question of its potential key role as a predator species. This makes this mustelid a predator with greater prey diversity than previously thought and elucidate aspects of the natural history of trophic ecology of tayra, grey brocket deer and others elusive forest species.