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

• Published in: Communications biology Vol. 1; no. 1; p. 109
• Main Authors: van Casteren, Adam, Oelze, Vicky M., Angedakin, Samuel, Kalan, Ammie K., Kambi, Mohamed, Boesch, Christophe, Kühl, Hjalmar S., Langergraber, Kevin E., Piel, Alexander K., Stewart, Fiona A., Kupczik, Kornelius
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10-08-2018; Nature Publishing Group
• Subjects: 631/158; 631/158/2466; 631/181/19/2471; Biology; Biomedical and Life Sciences; Environmental conditions; Food sources; Forests; Incisors; Isotopes; Life Sciences; Mechanical properties; Niches; Pan troglodytes; Savannahs; Teeth; Tropical forests
• ISSN: 2399-3642; 2399-3642
• DOI: 10.1038/s42003-018-0115-6

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.
Adam van Casteren et al. report that chimpanzee foods in savannah woodlands are more mechanically demanding than those in tropical forests. This study, based on carbon and nitrogen isotope signature analysis and measurements of the mechanical properties of common food sources, suggests that chimpanzees may adapt their dietary niche to environmental conditions.