Chimpanzee diet: Phytolithic analysis of feces

Abstract

Most primate populations remain unobservable; therefore, researchers depend on the analyses of indirect evidence encountered at a study-site in order to understand their behavioral ecology. Diet can be determined through the analyses of scats or feeding remains encountered on-site. This allows aspects of their dietary repertoire to be established, which has implications both for conservation efforts (by locating food resources), and for understanding the evolution of hominin diet (if used as referential models). Macroscopic inspection of fecal samples is a common method applied to ascertain a primate population's diet. However, new approaches are required to identify food-items unrecognizable at this level. We applied a dry ash extraction method to fecal samples (N=50) collected from 10 adult chimpanzees in Kanyawara, Kibale National Park, Uganda and also to plant parts (N=66) from 34 species known to be included in the diet of this community of apes. We recovered phytoliths in 26 of the 34 plant species. Fifteen phytolith morphotypes were only detected in 14 plant species (termed "distinct" phytoliths). We used these distinct phytoliths to identify plant foods (i.e., that they were associated with) in fecal samples. We then validated findings by checking if the 10 chimpanzees had eaten parts of these plants ∼24 hr prior to fecal sample collection; six plant species associated with five distinct phytoliths had been eaten. Finally, we compared plant foods identified in fecal samples from phytolith analyses with plants that had been identified from macroscopic inspection of the same fecal samples. Findings from phytolith analyses corroborate with those from macroscopic inspection by expanding the total number of plant species identified per fecal sample (i.e., we identified certain plant parts that remained unrecognizable at macroscopic level). This study highlights the potential of phytolith analyses of feces to increase our knowledgebase of the dietary repertoire of primate populations.

Dental calculus evidence of Taï Forest Chimpanzee plant consumption and life history transitions

“…However, many approaches to dietary reconstruction leave unanswered specific questions on diet and related life history events, especially for fossil specimens. There is a need for new methods to reconstruct food acquisition from populations that can avoid some of the shortfalls of other techniques like direct observation, stable isotope analysis and microwear studies 5 6 . In some contexts direct observation is simply not possible, for example with extinct great apes and human groups.…”

Chimpanzee (Pan troglodytes verus) Diet Composition and Food Availability in a Human-Modified Landscape at Lagoas de Cufada Natural Park, Guinea-Bissau

“…As we used sieves of 1 mm mesh, consumption of foliage and flower items may be higher than what we report herein. In spite of its limitations, some of which may be overcome by phytolith analyses (Phillips and Lancelotti 2014) or DNA-based techniques (Quéméré et al 2013), macroscopic analysis of feces is useful to expand the variety of known dietary constituents (McGrew et al 2009;Phillips and McGrew 2013). Also, it can be used as a rough proxy of the time spent feeding on different items, as the percentage volume of food items in feces gives similar results to feeding observations (Phillips and McGrew 2014).…”

The representativeness of the dental calculus dietary record: insights from Taï chimpanzee faecal phytoliths

“…In some archaeological contexts, phytolith assemblages are mostly composed of digested phytoliths (Albert et al 2008). Though phytoliths that pass through the gastrointestinal tract have been studied for their potential for reconstructing human behaviour (Gur-Arieh et al 2014;Phillips and Lancelotti 2014;Shahack-Gross 2011), few studies have examined the impact of this process on the assemblages. It is not clear how mammalian digestion affects phytoliths, despite the fact that phytoliths are frequently encountered damaged, and we need to understand the damage patterns that often affect them (Madella and Lancelotti 2012).…”