The first known observations of chimpanzees preying on hinge-back tortoises are described in a study in Scientific Reports.
Chimpanzees were previously known to hunt and consume the meat of various animals, but there have been no direct observations of tortoise predation by chimpanzees to date.
Simone Pika and colleagues describe this behaviour in a group of wild chimpanzees of the Rekambo community, living in the Loango National Park, Gabon. Between July 2016 and May 2018, the authors observed 38 prey events in ten different chimpanzees, of which 34 were successful. Tortoise predation was observed frequently in most or all of the studied adult chimpanzee males. It consisted of a distinct sequence of behaviours involving the discovery of the prey, followed by smashing the tortoise shell (plastron) with one hand against a hard surface, such as a tree trunk. The chimpanzees then climbed a tree to consume the meat. In 23 of the 38 observed prey events, the food was shared with other group members, including those who had previously attempted to open the tortoise shell but not succeeded.
It is known that chimpanzees have developed a large and varied repertoire of tool use; for example, using spear-like tools to rouse prey from cavities. The observations made in this study shed new light on the percussive technology used by chimpanzees to open food items such as nuts, hard-shelled fruit and snails by pounding them against hard surfaces or using hammers. They also provide further support for chimpanzees’ large and flexible cognitive abilities and, possibly, future planning, according to the authors.