Did Panthera pardus (Linnaeus, 1758) become extinct in Sumatra because of competition for prey? Modeling interspecific competition within the Late Pleistocene carnivore guild of the Padang Highlands, Sumatra

On the Island of Sumatra, the leopard (Panthera pardus) became extinct during the Late Pleistocene. Several theories exist about the reasons why leopards could not subsist in Sumatra, while today, national parks still bear tigers (Panthera tigris) and Asiatic wild dogs (Cuon alpinus). One often debated theory is that the competition for prey was the reason for the extinction of leopards in Sumatra. The aim of our study is to model the impacts of competition for prey in the carnivore guild of the Padang Highlands in Sumatra to test if competition pressure was sufficient to force the leopard to extinction. In the first step, we reconstructed the carnivore guild of the Padang Highlands based on fossils collected by Dubois in the three cave sites of Sibrambang, Djamboe and Lida Ajer. In the second step, we developed and applied an agent-based model based on population density, prey spectrum and daily meat intake and simulated different scenarios of competition among the Sumatran predators. We simulated the reconstructed guild and further tested scenarios with the absence of guild members to see under which circumstances leopards could have survived in Sumatra. Simulation of the reconstructed carnivore guild revealed that, in fact, the leopard could have been driven to extinction by competition from other carnivores. Excluding one of the competing medium-sized cats or the Asiatic wild dog leads to the survival of the leopard in our simulations. Interestingly, our model demonstrates that humans and tigers were not the strongest competitors for leopards because their exclusion from the scenarios does not conclude with the survival of leopards in our simulations. According to our results, the presence of two medium-sized cats and the Asiatic wild dog, in combination with the small litter size of the leopard, were the main reasons why the leopard could not tolerate the competition for prey in the Padang Highlands in Sumatra and thus became extinct in Sumatra.