The interaction between native and exotic species can cause changes both in the food-chain and in aspects of competition for trophic resources, such as predation. Predatory events are common in nature, but difficult and usually recorded opportunistically. Here we present the first report of trophic interaction involving a species of exotic bird (Melopsittacus undulatus) and a species of native primate (Sapajus cay). Capuchin monkeys have already been recorded feeding on a wide variety of vertebrates, including frogs, lizards, birds, mammals, and even other species of primates. Although the record of the non-native M. undulatus in the state of Mato Grosso do Sul indicates a possible domestic escape, the record of predation may represent a beneficial trophic interaction for the ecosystem, preventing M. undulatus from becoming an invasive alien species. Studies are needed to assess what risks are posed by domestic species being preyed upon by native species.

This study presents the first record of Myocastor coypus in the state of Mato Grosso do Sul, in addition to detailing its distribution within southern South America, highlighting where it is considered native or exotic in Brazil. On April 23, 2018, at approximately 18:00, an adult specimen with a 40 cm BL (body length) was registered after being run over on a side road near wetlands and a dam in a rural area in the municipality of Bataguassu, eastern state of Mato Grosso do Sul. It is not possible to state the origin of the M. coypus reported in the present study; whether it was introduced or dispersed naturally through the flooded areas of the Paraná River, since the species has records on the border of the states of Mato Grosso do Sul and Paraná.

Caimans of the species Caiman latirostris, which are widely distributed in South America, are opportunistic predators. They show ontogenetic variation in diet, with young individuals initially feeding on invertebrates and then gradually adding vertebrates in their diets as they grow up. However, due to inexperience, young individuals may end up eating dangerous prey, such as poisonous amphibians. The intoxication caused by eating an individual of Rhinella diptycha may produce local irritation to the caiman, and even lead it to death shortly after ingestion. To avoid this threat, some animals use particular feeding strategies, such as starting to eat the prey’s posterior part, or eating only its viscera. In this note, we report the first case of a predation event of an adult individual of the poisonous toad R. diptycha by a young individual of C. latirostris that we observed in a pond of the Southeast of Brazil. The caiman waited until the toad was dead before starting swallowing slowly, from the anterior part of the body. We did not observe any sign that the caiman was affected by the prey ingestion, even some hours later after ingestion. Our register suggests that the caiman may be tolerant or adapted to eat this poisonous prey and encourage research on the causes and mechanisms of this tolerance.