Predation on mammals by the chimpanzee (Pan troglodytes)

Abstract

ABSTRACT. With respect to prey selectivity and predation frequency, chimpanzees (Pan troglodytes) show local differences as well as diachronic variability within the same population. When data on predation from three long-term studies at Mahale, Gombe, and Tai are compared, some differences and similarities emerge; Mahale is more like Gombe than Tai in regard of prey selection but features of hunting at Tai with respect to predation frequency are not conspicuous. The most responsible factor for diversity in prey selectivity is a distinct "prey image" maintained by chimpanzees of different populations, although it is necessary to clarify in future studies why and how such tradition develops. Relative body size of chimpanzees to prey species and/or the degree of cooperation among members of a hunting party may explain the variability in prey size selected at each site, the latter influencing the frequency of successful hunts at the same time. Although various degrees of habituation and different sampling methods including artificial feeding might have obscured the real differences, recent data from the three populations do not seem to be biassed greatly by such factors. Nevertheless, it is still difficult to make strict comparisons due to the lack of sufficient standardized data across the three populations on the frequency of hunting and predation. It is suggested that the size or demographic trend of a chimpanzee unit-group, especially the number of adult males included, necessarily influences its hunting frequency as well as its prey profile. It is also suggested that factors which bring these males together into a party (e.g. fruit abundance, swollen females, conflict between unit-groups etc.) strongly affect the actual hunting and kill rates. Other possible factors responsible for the local differences are forest structure (e.g. tree height), skilful "hero" chimpanzees, and competition with sympatric carnivorous animals. A total of at least 32 species have been recorded as prey mammals of chimpanzees from 12 study sites and the most common prey mammals are primates (18 species), of which 13 species are forest monkeys. Forest monkeys, colobine species in particular, are often the most common victims of the predation by chimpanzees at each site. We may point out a tendency toward selective hunting for the forest monkeys in terms of the selectivity of prey fauna among all three subspecies of chimpanzees, including populations living in drier environment. The mode of chimpanzee hunting seems to correspond to the highest available biomass of gregarious, arboreal monkeys in the forest, colobine species in particular. In contrast, bonobos (P. paniscus) are less carnivorous than chimpanzees, only rarely preying on a few species of small mammals. The sharp contrast of the two allied species in their predatory tendencies appears to have something to do with the differences in the structure of primary production between their habitats.

The meat-scrap hypothesis: small quantities of meat may promote cooperative hunting in wild chimpanzees (Pan troglodytes)

“…Chimpanzees prey most frequently upon red colobus monkeys (Procolobus spp.) at all sites where the two species are present (Uehara 1997;Boesch and Boesch-Achermann 2000;Mitani and Watts 2001). To date, the precise nutritional significance of meat for chimpanzees is unknown.…”

Taphonomic analysis of skeletal remains from chimpanzee hunts at Ngogo, Kibale National Park, Uganda

“…However, less prevalent in the zooarchaeological literature are taphonomic test criteria for recognizing early hominin hunting and consumption of small prey. Chimpanzee dietary behavior can inform this argument because although chimpanzees have been observed to occasionally scavenge (Hasegawa et al, 1983;Nishida, 1994;Muller et al, 1995), they acquire most of their meat by hunting (Uehara, 1997;Stanford, 1998;Mitani and Watts, 1999;Boesch and Boesch-Achermann, 2000), and therefore may provide an example of the bony assemblage produced by a primate that hunts small-sized vertebrate prey.…”

“…Studies of chimpanzee hunting behavior in the wild have yielded considerable information about prey selection and hunting participation, frequency, and success (e.g., Uehara, 1997;Stanford, 1998;Mitani and Watts, 1999;Boesch and Boesch-Achermann, 2000;Watts and Mitani, 2002). Chimpanzees hunt vertebrate prey everywhere that they have been studied in any detail (Uehara, 1997; Table 1).…”

“…Chimpanzees hunt vertebrate prey everywhere that they have been studied in any detail (Uehara, 1997; Table 1). While 38 species of Table 1recorded Kawanaka, 1982;Takahata et al, 1984).…”

<Note> Exploratory-threat behaviors in wild chimpanzees encountering a porcupine

“…Aggressive behaviors of chimpanzees toward another species have been observed during hunting 1 , counterattack against a predator 2,3 , and cross-species play or playful teasing 2,4 . The threat-like displays observed in this study were not considered hunting attempts, since there is no record of chimpanzees hunting porcupines 1 and the displays were not as vigorous or the chimpanzees as excited as during genuine hunting.…”