Novelty Response of Wild African Apes to Camera Traps

Temperament and personality research in humans and nonhuman animals measures behavioral variation in individual, population, or species-specific traits with implications for survival and fitness, such as social status, foraging and mating success [1–5]. Curiosity and risk-taking tendencies have been studied extensively across taxa by measuring boldness and exploration responses to experimental novelty exposure [3,4,6–15]. Here, we conduct a natural field experiment using wildlife monitoring technology to test variation in the reaction of wild great apes (43 groups of naïve chimpanzees, bonobos and western gorillas, across 14 field sites in Africa) to a novel object, the camera-trap. Bonobo and gorilla groups demonstrated a stronger looking impulse towards the camera-trap device compared to chimpanzees, suggesting higher visual attention and curiosity. Bonobos were also more likely to show alarm and other fearful behaviors, although such neophobic (and conversely, neophilic) responses were generally rare. Among all three species, individuals looked at cameras longer when they were young, were associating with fewer individuals, and did not live near a long-term research site. Overall, these findings partially validate results from great ape novelty paradigms in captivity [7,8]. We further suggest that species-typical leadership styles [16] and social and environmental effects, including familiarity with humans, best explain novelty responses of wild great apes. In sum, this study illustrates the feasibility of large-scale field experiments and the importance of both intrinsic and extrinsic factors in shaping animal curiosity

Importance of subterranean fungi in the diet of bonobos in Kokolopori

Nonstaple food is a food resource which sole consumption does not allow the maintenance of regular physiological functions, thus constituting a minor portion of an individual's diet. Many primates consume nonstaple food such as meat, insects, and fungi. Hypotheses on the dietary importance of nonstaple food include its role as fallback food and as source of specific nutrients. We tested these two hypotheses by investigating mycophagy (i.e., the consumption of fungi) in a population of wild bonobos in the Kokolopori Bonobo Reserve, DRC. Specifically, we examined the relationship between fungus consumption and various factors relevant to bonobo feeding ecology (i.e., fruit abundance and the consumption of other food types). Additionally, we measured the deviation from linear travel when bonobos searched for fungi to evaluate the nature of fungus consumption (e.g., opportunistic or targeted). Lastly, we examined the nutritional content of the major fungus species consumed (Hysterangium bonobo) to test whether this food item was potentially consumed as source of specific nutrients. We found that bonobos spent a higher proportion of their time feeding on fungi when fruit abundance was higher, indicating that fungi were not consumed as a fallback food. Moreover, bonobos deviated from linear travel when visiting fungus patches more than observed when visiting fruit patches, suggesting that they actively sought out fungi. Lastly, initial analyses suggest that H. bonobo samples contained high concentration of sodium. Collectively, these results suggest that subterranean fungi appear to be attractive food source to Kokolopori bonobos, and that mycophagy may serve to supplement nutrients, like sodium, in bonobo diet