Food mechanical properties and isotopic signatures in forest versus savannah dwelling eastern chimpanzees

Abstract

Chimpanzees are traditionally described as ripe fruit specialists with large incisors but relatively small postcanine teeth, adhering to a somewhat narrow dietary niche. Field observations and isotopic analyses suggest that environmental conditions greatly affect habitat resource utilisation by chimpanzee populations. Here we combine measures of dietary mechanics with stable isotope signatures from eastern chimpanzees living in tropical forest (Ngogo, Uganda) and savannah woodland (Issa Valley, Tanzania). We show that foods at Issa can present a considerable mechanical challenge, most saliently in the external tissues of savannah woodland plants compared to their tropical forest equivalents. This pattern is concurrent with different isotopic signatures between sites. These findings demonstrate that chimpanzee foods in some habitats are mechanically more demanding than previously thought, elucidating the broader evolutionary constraints acting on chimpanzee dental morphology. Similarly, these data can help clarify the dietary mechanical landscape of extinct hominins often overlooked by broad C3/C4 isotopic categories.

Stable isotope variation in savanna chimpanzees (Pan troglodytesverus) indicate avoidance of energetic challenges through dietary compensation at the limits of the range

“…Average Δ 13 C and Δ 15 N values per Pan research site; size of points denotes relative sizes of hair datasets (range: 6–36). Δ values are calculated based on the following hair and plant datasets: Oelze et al, ; Loudon et al, ; van Casteren et al, ; this study…”

“…Pan species are frequently used as referential models for hominin ecology and dietary reconstruction; therefore these species have likewise represented a particular focus within primate isotopic research (e.g., Carter, ; Fahy, Boesch, Hublin, & Richards, ; Fahy, Richards, Riedel, Hublin, & Boesch, ; Macho, ; Macho & Lee‐Thorp, ; Oelze et al, ; Oelze, Head, Robbins, Richards, & Boesch, ; Schoeninger, Moore, & Sept, ; Schoeninger, Most, Moore, & Somerville, ; Smith, Morgan, & Pilbeam, ; Sponheimer et al, ; van Casteren et al, ). As a result, Pan isotope ecology has developed into a growing discipline in which both broad‐ and fine‐scale dietary variation within and between individuals have been detected noninvasively.…”

“…Within Pan isotope ecology, particular focus has been placed on chimpanzees in more open mosaic habitats due to their use as referential models for human evolution. To date, data from a growing number of sites have been published (Ugalla, Ishasha: Schoeninger et al, , Gombe: Schoeninger et al, , Fongoli: Sponheimer et al, , Kayan: Oelze et al, , Issa: van Casteren et al, ), however each employ starkly different sampling approaches, and the majority of these studies lack baseline environmental data. Here we describe patterns of isotopic variation in chimpanzees inhabiting a savanna environment along a latitudinal gradient in Senegal, at the northwestern reaches of chimpanzee distribution in Africa.…”

Periapical lesions in hominids: Abscesses on the maxilla of a 2 million‐year‐old early Homo specimen

“…G. gorilla gorilla is known to fracture canines regularly and also exhibit extensive anterior tooth wear and damage, to explain their pattern (Schultz, ). P. troglodytes not only have similar issues with their canines but also use their anterior teeth extensively in food processing, likely explaining the high prevalence of lesions (Hylander, ; McGrew, ; van Casteren et al, ). Therefore, the results for extant primates suggest that these bony lesions may be a useful indicator of diet, behaviour, and health in fossil samples.…”

Limited evidence of C4 plant consumption in mound building Macrotermes termites from savanna woodland chimpanzee sites

“…[1,2]). This bias towards a small number of chimpanzee communities has been tempered by the increasing use of indirect methods, such as stable isotope analysis, that enable large-scale cross site comparisons of the various feeding behaviors of both habituated and unhabituated chimpanzee communities [3][4][5][6][7][8][9][10]. Insights obtained from such studies are only as good as our understanding of the various stable isotope ratios, such as carbon (δ 13 C) and nitrogen (δ 15 N), of consumed organisms by chimpanzees at different locales [3][4][5][11][12][13].…”