The study of the competitive interactions between predators has traditionally been approached within the context of predatory behavior. By using a quasi-experimental, non-intrusive approach, we go beyond the classical view that predators only compete for living prey and disentangle the mechanisms of exploitative and interference competition between two charismatic apex predators, lions (Panthera leo) and spotted hyaenas (Crocuta crocuta), at carcasses other than their own kills. Carcasses of different sizes were monitored in two study areas of South Africa: one with both lions and hyaenas and the other with hyaenas only. We found evidence of both symmetric exploitative competition and asymmetric interference competition. Interactions were strongly conditioned by carcass size, and co-occurrence was mostly recorded at large ungulate carcasses. Interference competition seemed to dominate interspecific interactions, with lions having preferential access. However, interference while feeding did not exert any cost on the subordinate hyaenas, in terms of amount of ingested food and consumption rate, probably thanks to the reward provided by large carcasses in the form of abundant carrion, the use of lions to detect carcasses, and spatiotemporal segregation at the carcass-scale. Securing a diverse carrion supply in terms of carcass size, including megaherbivore carcasses, may favor the coexistence of the largest African carnivores, especially in small protected areas. Overall, our study reveals mechanisms related to both the food resource characteristics and the competitor behavior that allow the coexistence of strongly interacting species.

Data were obtained through camera-trapping.