Ontogenetic shifts, trophic differentiation, and predator–prey size relationships in Oxyrhopus false coral snakes from Bahia, Brazil

Although snakes of the genus Oxyrhopus are generally regarded as opportunistic predators, the relative roles of interspecific dietary differentiation, ontogenetic variation, and predator morphology in their feeding ecology remain poorly understood. We analyzed the diet of 253 preserved specimens representing four Oxyrhopus species from Bahia, Brazil. Dietary composition was quantified using the Index of Relative Importance (%IRI), trophic overlap was estimated using Pianka’s niche overlap index, and ontogenetic and morphological variation in prey use were evaluated using multivariate and linear models. Species differed in dietary composition and generally showed low trophic overlap, indicating differences in prey use among species. Juveniles consumed predominantly lizards, whereas adults incorporated proportionally more mammals and birds. Prey size increased with snake body size, whereas ontogenetic stage itself was not consistently associated with prey size. Head width was positively associated with prey width, indicating a relationship between predator cranial dimensions and prey dimensions. Because specimens were collected across different localities and were not necessarily syntopic, the observed differences should not be interpreted as direct evidence of local resource partitioning or competition. Overall, our results highlight interspecific and ontogenetic variation in prey use and provide a comparative assessment of dietary patterns and predator–prey size relationships in Oxyrhopus from Bahia.