Insectivory of savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal

Abstract

Little is known about the behavior of chimpanzees living in savanna-woodlands, although they are of particular interest to anthropologists for the insight they can provide regarding the ecological pressures affecting early hominins living in similar habitats. Fongoli, Senegal, is the first site where savanna chimpanzees have been habituated for observational data collection and is the hottest and driest site where such observation of chimpanzees occurs today. Previously, indirect evidence suggested these chimpanzees consumed termites throughout the year, an unusual occurrence for western and eastern chimpanzees. Although meat eating by chimpanzees continues to receive much attention, their use of invertebrate prey has received less emphasis in scenarios of hominin evolution. Here, we further examine the invertebrate diet of Fongoli chimpanzees using direct observational methods and accounting for potential environmental influences. Termite feeding positively correlated with high temperatures. Fongoli chimpanzees spend more time obtaining termites than any other chimpanzee population studied, and this extensive insectivory contributes to the list of distinctive behaviors they display relative to chimpanzees living in more forested habitats. We suggest that savanna chimpanzees at Fongoli differ significantly from chimpanzees elsewhere as a result of the selective pressures characterizing their harsh environment, and this contrast provides an example of a viable referential model for better understanding human evolution. Specifically, our results support the hypotheses that invertebrate prey may have figured more prominently into the diet of early hominins in similar habitats, especially given that invertebrates are an important source of protein and other essential nutrients in a highly seasonal environment.

Ecological and social correlates of chimpanzee tool use

“…In addition, the average length of termite fishing bouts in the Goualougo Triangle was relatively short (average duration + s.d. ¼ 6.05 + 2.55 min, n ¼ 11 individuals, totalling 463 bouts) when compared with other sites (average termite fishing bouts of 22.6 min were reported from the wet season, and 33.6 min in the dry season at Fongoli, Senegal) [35].…”

“…Some habitats in which these primates live may not offer traditional fallback foods, and so primates are prompted to procure higher quality resources when their staple food items are scarce. This could be the case with the seafood harvesting macaques on islands in the Andaman Sea [77] or the termite harvesting chimpanzees of Fongoli in Senegal [35,78]. Further, tool use may also be necessitated in localities where feeding competition within or between species is high [26].…”

“…By contrast, termite fishing has been documented throughout the year at several sites within central Africa [37,[49][50][51][52] and at the savannah site of Fongoli in West Africa [35]. In central Africa, chimpanzees have developed specialized tool sets to harvest termites year-round [52 -54], and ecological opportunities to harvest termites seem to be particularly abundant at Fongoli where these insects are a staple food in the chimpanzee diet [35]. By contrast, termite nests are rare and peripheral to the chimpanzee range at Seringbara in Guinea, and no evidence of tool use in this context has been detected within this population [32].…”

Comparative isotope ecology of African great apes

“…The consumption of C4-resources by savanna chimpanzees has been questioned partly because previous isotope studies were uncertain about the local vegetation isotope baselines (Schoeninger et al, 1999;Sponheimer et al, 2006a). At the time of our study, more than 65% of the habitat at Fongoli consisted of wooded grassland containing C4-plants such as elephant grass (Bogart and Pruetz, 2011) 30 which could be an important dietary source for termites and other chimpanzee prey species.…”

A preliminary checklist of the ant (Hymenoptera, Formicidae) fauna of Senegal

“…Presence data can also be deduced from papers studying the ecology and/or the behaviour of some ant species (Agbogba 1991;1992;Agbogba & Howse 1992;Gillon et al 1984). Other have reported the participation of ant species in the diet of animals such as Chimpanzees (Bogart & Pruetz 2011;McGrew et al 2005).…”