Baboon Diet: A Five-Year Study of Stability and Variability in the Plant Feeding and Habitat of the Yellow Baboons (Papio cynocephalus) of Mikumi National Park, Tanzania

Abstract

The habitat and plant feeding of 64 well-habituated, individually identified adult male and female yellow baboons was studied for 5 years at Mikumi National Park, Tanzania. Variation across the years showed that a study of only one or two years would have been incomplete and misleading. The list of baboon food species obtained from Mikumi is considerably larger and more diverse than any previously reported. One to six plant parts were eaten from each of more than 180 species. The 25 most common tree genera all contained species used for food. Of the 50 most common grass, shrub and herb genera, 93% included plant foods. Using months in which a species was eaten during at least one year of the study, 21 staple species were eaten during a mean of 8.86 months and 7 were eaten in all 12 months. Although many foods were from commonly available plant species, 15 such species were only rarely eaten. The number of parts of a species eaten per month and an estimate of the amounts eaten per month both varied with temperature and rainfall, being lowest near the end of the cool, dry season. There were substantial differences from year to year in the timing and amount of food production of many species; nevertheless, the same broad feeding pattern was repeated in each of the 5 years of the study. Despite yearly variation in food availability, 14 or more staples and other common foods were eaten in any given month. If crops of many of these foods were to fail, a large number of less commonly eaten species could be substituted. Baboons are eclectic feeders that appear to be optimizing their diet by selective feeding from among a wide array of available foods in an ever-changing floristic environment.

What Insights Can Baboon Feeding Ecology Provide for Early Hominin Niche Differentiation?

“…For the most part, baboons within a given region appear to develop a fixed or staple diet, most evinced in the smaller degree of variation between hair and tooth samples than intraindividually (Codron et al 2006). In field studies of baboons in southern and East African environments, Norton et al (1987) and Byrne et al (1993) made similar observations, in that staple food items of populations remain fairly consistent through time with only perimeter items varying in substantial ways The implication is that australopiths were either even more generalist than baboons, or that the variation in early hominin enamel δ 13 C likely represents individuals from different populations isolated in space or time. Fecal samples collected at monthly intervals portray a similarly high degree of variation as exists across multiple hominin enamel specimens, but the 2 lines of evidence are not strictly comparable because of the short-term nature of feces as dietary indicators.…”

“…In field studies, Altman (1998), Barton et al (1993), Byrne et al (1993), DeVore and Hall (1965), Dunbar and Dunbar (1974), Norton et al (1987), Whiten et al (1991), and others revealed that baboon diets, excluding the primarily stenotopic graminivore Theropithecus gelada, vary in extreme ways. Stable isotope ecology is one tool that enables researchers to characterize and to quantify at least some aspects of diet in these and other generalist feeders in easily understandable terms.…”

Optimal group size in a highly social mammal

“…Our investigation provides an important extension of previous research on optimal group size, which has focused predominantly on fission-fusion species, in which group size changes frequently in response to immediate conditions (25). Within a baboon population, the home ranges of social groups overlap extensively, and foraging resources [primarily plant foods (26,27)], are often located within regions of home range overlap (28). However, despite this home range overlap, groups rarely come in close proximity with one another, indicating that baboon groups temporally partition the landscape, using the same resources but at different times (29).…”

Molar microwear textures and the diets ofAustralopithecus anamensisandAustralopithecus afarensis

“…Orangutans are intermediate in their diets. Finally, geladas are specialized grass eaters, whereas yellow baboons have a more catholic diet including fruits, leaves and animal prey (see Post 1982;Norton et al 1987;Dunbar 1988;Altmann 1998;Pochron 2000;Bentley-Condit 2009). …”