Wild chimpanzees (Pan troglodytes troglodytes) exploit tortoises (Kinixys erosa) via percussive technology

Abstract

Chimpanzees ( Pan troglodytes ), one of humankinds’ closest living relatives, are known to hunt and consume the meat of various animal taxa. Although some researchers have presented indirect evidence that chimpanzees may also prey on tortoises, until now, direct observations of this behaviour did not exist. Here, we provide systematic descriptions of the first observations of chimpanzee predation on tortoises ( Kinixys erosa ). We made these unprecedented observations on newly habituated chimpanzees ( Pan troglodytes troglodytes ) of the Rekambo community, living in the Loango National Park, Gabon. The behaviour qualified as customary, that is occurring in most or all adult males, involved a distinct smashing technique, and resulted frequently in food sharing with other group members. Our observations shed new light on the hitherto little understood percussive technology of chimpanzees, and expand our current knowledge on chimpanzees’ dietary and predatory repertoires with respect to reptiles. We also report a case of food storage and discuss it in the context of future-oriented cognition. Our findings suggest the need for more nuanced interpretations of chimpanzees’ cognitive skills in combination with an in-depth understanding of their unique socio-ecological niches. They further emphasize the importance of nonhuman primate field observations to inform theories of hominin evolution.

Gorillas’ (Gorilla g. gorilla) knowledge of conspecifics’ affordances: intraspecific social tool use for food acquisition

“…These findings, along with the scarce literature on social tool use (chimpanzees, orangutans, and Japanese macaques: Völter et al 2015 ; Schweinfurth et al 2018 ; Tokida et al 1994 ; keas: Tebbich et al 1996 ), suggest that (1) the foraging context may be a useful candidate for investigating social tool use in the lesser-known and under-documented gorillas in terms of socio-cognitive skills, and (2) some features of social tool use might have evolved across different vertebrate lineages (primates and birds) through convergent evolution rather than only phylogenetic continuity. Our findings further emphasise the suggestion by Pika et al ( 2019 ) that “reliable insights into the purpose cognitive abilities serve can only be gained by unravelling specific socio-ecological factors triggering their usage—a task demanding careful, knowledgeable observations of species living in their natural environments.” Deeper investigations of the ecological, social, and cognitive bases of social tool use in a wider range of primate species and in other lineages are necessary to improve our understanding of the evolutionary origins of human social manipulation.…”

Hunting of mammals by central chimpanzees (Pan troglodytes troglodytes) in the Loango National Park, Gabon

“…In the second event, occurring 8 months later, at least three adult individuals killed and consumed a yellow-backed duiker fawn. Hence, this observation provides further evidence for the diversity of chimpanzee feeding ecology (Pika et al 2019).…”

“…; ungulates: Cephalophus spp.) (Wrangham 1977;Goodall 1986;Watts and Mitani 2002;Yu et al 2013;Pika et al 2019). Concerning mammals, predation has been observed at all long-term study sites including Gombe (Goodall 1986) and Mahale (Nishida et al 1979) in Tanzania, Ngogo (Mitani and Watts 2001), Budongo (Newton-Fisher 2007) and Kanyawara (Gilby and Wrangham 2007) in Uganda, Taï in Côte d'Ivoire (Boesch and Boesch 1989), Bossou in Guinea (Sugiyama and Koman 1987), Fongoli in Senegal (Pruetz 2006), and Goualougo in the Republic of Congo (Morgan and Sanz 2006).…”

Chimpanzees foraging on aquatic foods: algae scooping in Bossou

“…Coincidentally, the paper on crab fishing appeared in parallel with another interesting paper on tortoise hunting (Pika et al 2019). Chimpanzees (Pan troglodytes troglodytes) living in the Loango National Park, Gabon, provided the first observations of chimpanzee predation on tortoises (Kinixys erosa).…”