Living in Fear: Causes and contexts of great ape attacks on local persons

Attacks on humans by wildlife are a leading cause of ‘human–wildlife conflict’ and are likely on the rise due to growing human populations and increased spatial overlap with wild animals. Large mammals attack hundreds of... [ view full abstract ]

Attacks on humans by wildlife are a leading cause of ‘human–wildlife conflict’ and are likely on the rise due to growing human populations and increased spatial overlap with wild animals. Large mammals attack hundreds of people globally each year. To date, little attention has focused on attacks by great apes compared to other large mammals, especially large carnivores and large herbivores. We reviewed reports of wild ape aggression towards, and attacks on, local persons in Africa and Asia to better understand their causes and contexts. We find that physical attacks on humans by great apes are overall rare. Most reports involve chimpanzees and, to a lesser extent, gorillas; wild orangutans and bonobos seem to rarely attack humans. Most gorilla attacks target adult humans and are motivated by defensive instincts (e.g., in response to hunting threat). In contrast, victims of chimpanzee attacks are overwhelmingly children, and attacks fall more evenly into provoked (i.e., in response to harassment) and unprovoked categories (e.g., predation on young children). Among great apes, an increased propensity of chimpanzees to attack humans is likely due to a combination of greater ecological flexibility that enables them to exploit disturbed habitats near people, their multi-male social systems, tendencies for aggressive behaviours in day-to-day life, and more prevalent hunting behaviour. Improved knowledge of the contexts and causes of ape attacks, along with a better understanding of human cultural attitudes and conflicts among different stakeholder groups involved with or affected by great ape conservation, can aid development of mitigation strategies to reduce likelihood of attacks.