The feeding behaviour of the puma (Puma concolor) is a fundamental characteristic that guarantees its evolutionary success. It is one of the primary factors associated with its widespread distribution, including hostile regions like the Brazilian Caatinga, a semi-arid biome. We investigate the feeding ecology of the puma in a protected area located in the Caatinga by describing its diet and evaluating patterns of prey selection mediated by energetic trade-off and meeting probability. We found ten prey species consumed by pumas, with the collared peccary (Pecari tajacu) representing almost half of consumed prey items. Prey selection by puma was correlated with an overlap of activity patterns between predator and prey, suggesting that meeting probability is an important topic in its foraging ecology. Due to the predominance of a single prey species, the puma showed a narrow niche breadth (standardised Levins’ index = 0.113), positing the collared peccary as a critical element in the persistence of puma in the area. The puma is commonly described as a generalist predator since it feeds on a broad range of species across its distribution area; however, our results and recent literature suggest a more specialised diet at a local scale. This apparent contradiction could indicate that the puma diet is subject to a hierarchical organisation on a spatial scale, in which different local specialisations and adaptive strategies would lead to a generalist feeding behaviour at the distributional scale. It is important to highlight that we did not find any evidence of livestock depredation, which is a significant result from a conservation perspective, which favours puma conservation in the study area.