The 87th Annual Meeting of the American Association of Physical Anthropologists (2018)

Is savannah food dustier? Comparisons of the external abrasive loads of chimpanzee plant foods


Max Planck Weizmann Center for Integrative Archaeology and Anthropology, Max Planck Institute for Evolutionary Anthropology

April 12, 2018 , Zilker 1/2/3 Add to calendar

Hard mineralized external particles have been shown to be very deleterious to teeth. Much discussion has arisen as to both the selection pressure this may have exerted on enamel and the influence these particles may have on the interpretation of dietary signals within dental tissues. Yet our knowledge of the distribution and morphology of dust particles on the outside of primate plant foods is limited. Here we used the plastic cleaning method to collect external abrasives from the exterior of chimpanzee foods (leaves, fruits). This was done in two contrasting environments: the tropical moist broadleaf forest (Ngogo, Uganda) and subtropical savannah woodland (Issa Valley, Tanzania) during dry seasons. We predicted that foods from the dryer and more open savannah woodland would have a higher particle density and display distinctive particle form compared to those of the forest. Preliminary results indicate that this may not be the case, because estimated density of particles per mm2 was almost identical in both locales (Ngogo = 2222.7±1319.4 and Issa = 1861.5±1310.1). Gross particle morphology also shared remarkable similarities. At both sites particles showed wide size variation in maximum diameter (ranges Ngogo = 1- 119µm, Issa = 1-187µm) but the vast majority remained small (mean, Ngogo = 5.35±5.20 µm, Issa = 5.38±5.21 µm). These results indicate that despite substantial differences in precipitation and canopy structure Aeolian born dust on foods remained rather constant in the two chimpanzee habitats. Therefore dust has to be considered a source of abrasion even in closed and moist environments.

This research was funded by the Max Planck Society