Sex Differences in the Diets of Forest-dwelling Baboons (Papio anubis)

Abstract

The ability to eat and switch between many food sources is an adaptative feeding strategy utilized for meeting nutritional needs across different environments, seasons, and physiological conditions. Baboons (genus Papio) excel at both dietary flexibility and foraging selectively, and consequently have one of the most widespread geographic distributions in the Order. To further expand to our understanding of baboon feeding ecology, I analyzed foraging activity and the nutritional characteristics of the diets of the relatively understudied rainforest baboons (Papio anubis) living in Kibale National Park, Uganda. I also investigated if there are differences in food type choice and in the nutritional composition of diets among adult males, adult females, and subadult males. Using long-term data collected by Wildlife Ecology & Nutrition Project, I analyzed foraging time budgets of 23 baboons in relation to both food types eaten and by plant species. I also conducted a preliminary assessment of the overall nutritional intake and diet composition of this study group. To investigate sex/age class differences, I compared both the time spent feeding on each major food type and the daily nutritional intake rates among the sex/age classes. Kibale baboons were found to have a diet composed of 44.6% fruits, 24.1% piths, 10.9% leaves, 5.8% gums, 5.8% seeds, 2.4% roots, 2.4% flowers, 2.2% leaf galls, 1.4% insects, and 0.4% bark. The baboons consumed a relatively high amount of easily digestible carbohydrates and a low amount of crude protein compared to many of the previously studied baboon populations. There were sex/age class differences in mean time spent feeding on insects (χ2(2) = 8.87, p = .01), with subadult males being observed to eat significantly more insects than adult males (p = \u3c 0.01), but not more than adult females (p = 0.06). My results also presented partial evidence that males may have proportionally more crude protein and fat in their diet compared to subadult males and adult females, while subadult males may have diets higher in digestible carbohydrates compared to adults. Most of the findings in this study reinforce established feeding patterns previously observed in baboons, but also support the idea that selective generalists often have diets unique to their environment. The study is less conclusive in terms of determining if there are sex differences in the diets of baboons but does provides pathways for future investigations