Nutritional Ecology of <Emphasis Type="Italic">Ateles chamek</Emphasis> in lowland Bolivia: How Macronutrient Balancing Influences Food Choices

All free-living animals must make choices regarding which foods to eat, with the choices influencing their health and fitness. An important goal in nutritional ecology is therefore to understand what governs animals’ diet selection. Despite large variation in the availability of different food items, Peruvian spider monkeys (Ateles chamek) maintain a relatively stable daily protein intake, but allow total energy intake to vary as a function of the composition of available food items. This is referred to as protein-dominated macronutrient balancing. Here we assess the influence of this nutritional strategy on daily and seasonal nutritional intakes, estimate the nutritional value of different foods, and interpret unusual food choices. We conducted continuous all-day observations of focal spider monkeys inhabiting a semideciduous forest in Bolivia. We recorded feeding events, collected foods, and analyzed their nutrient content. By using the Geometric Framework for nutrition, we show that individuals reached their daily end-point in nutrient space —balance between protein and nonprotein energy intake— by consuming nutritionally balanced foods or by alternating between nutritionally complementary foods. The macronutritionally balanced figs of Ficus boliviana were their primary staple food and therefore dominated their overall nutritional intake. Our results also demonstrate that spider monkeys consumed a diverse array of ripe fruits to overcome periods of fig scarcity rather than vice versa; they could obtain sufficient protein on a diet of pure fruit; and unripe figs constituted a nutritionally rewarding and reliable food resource. We hope that the approaches taken and the conclusions reached in this study will catalyze further inquiries into the nutritional ecology of frugivorous primates.     

Use of cultivated foods and matrix habitat by Bale monkeys in forest fragments: Assessing local human attitudes and perceptions

Primates inhabiting human-modified landscapes often exploit matrix habitat to supplement their diet with cultivated foods, at times resulting in economic losses and conflict with local people. Understanding human-nonhuman primate interactions and the attitudes and perceptions of local people towards crop feeding species are crucial to designing effective species-based management plans. Over a 12-month period, we used scan sampling to study the consumption of cultivated foods and matrix use patterns by two habituated groups of Bale monkeys (Chlorocebus djamdjamensis), Ethiopian-endemic bamboo specialists, in two forest fragments (Kokosa and Afursa) set amidst human settlements and farmland in the southern Ethiopian Highlands. Further, we conducted interviews with local people to document their attitudes and perceptions towards Bale monkeys at the two sites. We found that Bale monkeys at Kokosa, a more degraded habitat by most measures, consumed significantly more cultivated foods than their counterparts at Afursa. Moreover, Bale monkeys at Kokosa spent significantly more time in the matrix than in the forest habitat, while monkeys at Afursa spent significantly less time in the matrix than in the forest habitat. Not surprisingly, local people displayed a more negative attitude towards monkeys inhabiting Kokosa than those inhabiting Afursa. The differences in Bale monkey cultivated food consumption and matrix use patterns—as well as in local people's attitudes and perceptions towards Bale monkeys—between Kokosa and Afursa are probably associated with differences in habitat structure, degree of habitat alteration, and land-use practices between the sites. We conclude that to ensure long-term coexistence between Bale monkeys and local people in human-modified landscapes, it is vital to incorporate nearby matrix habitats into management plans and to work closely with local communities to develop effective nonlethal crop protection strategies, thereby reducing the likelihood of negative interactions between Bale monkeys and humans.     

The Nutritional Geometry of Resource Scarcity: Effects of Lean Seasons and Habitat Disturbance on Nutrient Intakes and Balancing in Wild Sifakas

Animals experience spatial and temporal variation in food and nutrient supply, which may cause deviations from optimal nutrient intakes in both absolute amounts (meeting nutrient requirements) and proportions (nutrient balancing). Recent research has used the geometric framework for nutrition to obtain an improved understanding of how animals respond to these nutritional constraints, among them free-ranging primates including spider monkeys and gorillas. We used this framework to examine macronutrient intakes and nutrient balancing in sifakas (Propithecus diadema) at Tsinjoarivo, Madagascar, in order to quantify how these vary across seasons and across habitats with varying degrees of anthropogenic disturbance. Groups in intact habitat experience lean season decreases in frugivory, amounts of food ingested, and nutrient intakes, yet preserve remarkably constant proportions of dietary macronutrients, with the proportional contribution of protein to the diet being highly consistent. Sifakas in disturbed habitat resemble intact forest groups in the relative contribution of dietary macronutrients, but experience less seasonality: all groups’ diets converge in the lean season, but disturbed forest groups largely fail to experience abundant season improvements in food intake or nutritional outcomes. These results suggest that: (1) lemurs experience seasonality by maintaining nutrient balance at the expense of calories ingested, which contrasts with earlier studies of spider monkeys and gorillas, (2) abundant season foods should be the target of habitat management, even though mortality might be concentrated in the lean season, and (3) primates’ within-group competitive landscapes, which contribute to variation in social organization, may vary in complex ways across habitats and seasons.     

Dietary generalists and nutritional specialists: Feeding strategies of adult female blue monkeys (Cercopithecus mitis) in the Kakamega Forest,Kenya

Generalist primates eat many food types and shift their diet with changes in food availability. Variation in foods eaten may not, however, match variation in nutrient intake. We examined dietary variation in a generalist‐feeder, the blue monkey (Cercopithecus mitis), to see how dietary food intake related to variation in available food and nutrient intake. We used 371 all‐day focal follows from 24 adult females (three groups) in a wild rainforest population to quantify daily diet over 9 months. We measured food availability using vegetation surveys and phenology monitoring. We analyzed >700 food and fecal samples for macronutrient content. Subjects included 445 food items (species‐specific plant parts and insect morphotypes) in their diet. Variation in fruit consumption (percentage of diet and total kcal) tracked variation in availability, suggesting fruit was a preferred food type. Fruits also constituted the majority of the diet (by calories) and some fruit species were eaten more than expected based on relative availability. In contrast, few species of young leaves were eaten more than expected. Also, subjects ate fewer young leaves (based on calories consumed) when fruit or young leaves were more available, suggesting that young leaves served as fallback foods. Despite the broad range of foods in the diet, group differences in fiber digestibility, and variation that reflected food availability, subjects and groups converged on similar nutrient intakes (grand mean ± SD: 637.1 ± 104.7 kcal overall energy intake, 293.3 ± 46.9 kcal nonstructural carbohydrate, 147.8 ± 72.4 kcal lipid, 107.8 ± 12.9 kcal available protein, and 88.1 ± 17.5 kcal structural carbohydrate; N = 24 subjects). Thus, blue monkeys appear to be food composition generalists and nutrient intake specialists, using flexible feeding strategies to regulate nutrient intake. Findings highlight the importance of simultaneously examining dietary composition at both levels of foods and nutrients to understand primate feeding ecology.     

The macronutrient composition of wild and cultivated plant foods of West African chimpanzees (Pan troglodytes verus) inhabiting an anthropogenic landscape

Agricultural expansion encroaches on tropical forests and primates in such landscapes frequently incorporate crops into their diet. Understanding the nutritional drivers behind crop-foraging can help inform conservation efforts to improve human-primate coexistence. This study builds on existing knowledge of primate diets in anthropogenic landscapes by estimating the macronutrient content of 24 wild and 11 cultivated foods (90.5% of food intake) consumed by chimpanzees (Pan troglodytes verus) at Bossou, Guinea, West Africa. We also compared the macronutrient composition of Bossou crops to published macronutrient measures of crops from Bulindi, Uganda, East Africa. The composition of wild fruits, leaves, and pith were consistent with previous reports for primate diets. Cultivated fruits were higher in carbohydrates and lower in insoluble fiber than wild fruits, while wild fruits were higher in protein. Macronutrient content of cultivated pith fell within the ranges of consumed wild pith. Oil palm food parts were relatively rich in carbohydrates, protein, lipids, and/or fermentable fiber, adding support for the nutritional importance of the oil palm for West African chimpanzees. We found no differences in the composition of cultivated fruits between Bossou and Bulindi, suggesting that macronutrient content alone does not explain differences in crop selection. Our results build on the current understanding of chimpanzee feeding ecology within forest-agricultural mosaics and provide additional support for the assumption that crops offer primates energetic benefits over wild foods.     

Diet of spider monkeys (Ateles geoffroyi) in Mesoamerica: current knowledge and future directions

Here we review all published articles and book chapters, as well as unpublished theses and data of Ateles geoffroyi diet to (1) summarize the literature; (2) synthesize general feeding patterns; (3) document plant taxonomic similarity in diet across study sites; and (4) suggest directions for future research and conservation priorities. We found 22 samples from five countries: Mexico, Guatemala, El Salvador, Costa Rica and Panama. Tropical wet forest is the most studied habitat (N=13 samples), followed by tropical dry forest (6) and tropical moist forest (3). Most samples have been carried out in large protected forests. In spite of showing an overall high dietetic diversity (364 species, 76 families), A. geoffroyi concentrated the majority of feeding time on a few species in the families Moraceae and Fabaceae. At all study sites fruits were the most common food item in the diet followed by leaves. Furthermore, a greater variety of food items and less fruit were consumed in forest fragments. These findings suggest that fruit shortage in fragments results in primates using foods of presumably lower energetic content such as leaves. Similarity in diet was higher among groups geographically closer to each other than among distant groups, showing that the floristic and phenological characteristics of the forest can influence diet composition. We conclude that several years of data are required to fully describe the dietary list of A. geoffroyi at any one site, as studies of the same group over different years shared as little as 56% of species. As most populations of A. geoffroyi live in highly fragmented landscapes, it is crucial to carry out studies in these areas to evaluate (1) changes in diet and activity patterns that may negatively affect survival; and (2) habitat attributes that may favor their persistence in altered landscapes.     

Feeding behavior and nutrient intake in spiny forest-dwelling ring-tailed lemurs (Lemur catta) during early gestation and early to mid-lactation periods: compensating in a harsh environment

Strong resource seasonality in Madagascar has led to the evolution of female feeding priority and weaning synchrony in most lemur species. For these taxa, pregnancy/early lactation periods coincide with low food availability, and weaning of infants is timed with increased resources at the onset of the rainy season. Reproductive females experience high metabolic requirements, which they must accommodate, particularly when food resources are scarce. Female ring-tailed lemurs (Lemur catta) residing in spiny forest habitat must deal with resource scarcity, high temperatures (～36-40°C) and little shade in early to mid-lactation periods. Considered "income breeders," these females must use resources obtained from the environment instead of relying on fat stores; thus, we expected they would differ from same-sized males in time spent on feeding and in the intake of food and nutrients. We investigated these variables in two groups (N = 11 and 12) of Lemur catta residing in spiny forest habitat during early gestation and early to mid-lactation periods. Focal animal data and food plant samples were collected, and plants were analyzed for protein, kcal, and fiber. We found no sex differences for any feeding or nutrient intake variable for the top five food species consumed. Females in early gestation spent more time feeding compared with early/mid-lactation. Physiological compensation for spiny forest-dwelling females may be tied to greater time spent resting compared with gallery forest conspecifics, consuming foods high in protein, calories, and water, reduced home range defense in a sparsely populated habitat, and for Lemur catta females in general, production of relatively dilute milk compared with many strepsirrhines.     

Tropical Biodiversity in Human-Modified Landscapes: What is our Trump Card?

Many conservationists are now convinced that the expansion of the world system of protected areas combined with appropriate levels of biodiversity persistence within human-modified landscapes would drastically mitigate the announced impoverishment of tropical biotas. In this context, an inherent/intrinsic biodiversity ability to persist and recover within human-modified landscapes has emerged as a ‘trump card’ in the conservation battle, renewing our hope in a more sustainable development of the tropical region. However, this optimistic perspective on the conservation value of human-modified landscapes sounds, a priori, a little unrealistic in face of the current knowledge on the nature of human environments and the spectrum of native species that is likely to persist there. Rather than relying on illusory levels of biodiversity resilience and consequent flexible land-use regulations, our real trump card reposes on a radical and ambitious shift from freely exploited landscapes to strictly managed ones, despite the misleading noise produced by those voices advocating for immediate and almost unlimited access to natural resources. Otherwise, we are condemning future human populations to live in biologically impoverished and fragile environments with limited opportunities for life support.     

Nutritional correlates of the “lean season”: Effects of seasonality and frugivory on the nutritional ecology of diademed sifakas

Primate field studies often identify “lean seasons,” when preferred foods are scarce, and lower‐quality, abundant foods (fallback foods) are consumed. Here, we quantify the nutritional implications of these terms for two diademed sifaka groups (Propithecus diadema) in Madagascar, using detailed feeding observations and chemical analyses of foods. In particular, we sought to understand 1) how macronutrient and energy intakes vary seasonally, including whether these intakes respond in similar or divergent ways; 2) how the amount of food ingested varies seasonally (including whether changes in amount eaten may compensate for altered food quality); and 3) correlations between these variables and the degree of frugivory. In the lean season, sifakas shifted to non‐fruit foods (leaves and flowers), which tended to be high in protein while low in other macronutrients and energy, but the average composition of the most used foods in each season was similar. They also showed dramatic decreases in feeding time, food ingested, and consequently, daily intake of macronutrients and energy. The degree of frugivory in the daily diet was a strong positive predictor of feeding time, amount ingested and all macronutrient and energy intakes, though season had an independent effect. These results suggest that factors restricting how much food can be eaten (e.g., handling time, availability, or intrinsic characteristics like fiber and plant secondary metabolites) can be more important than the nutritional composition of foods themselves in determining nutritional outcomes—a finding with relevance for understanding seasonal changes in behavior, life history strategies, competitive regimes, and conservation planning. Am J Phys Anthropol 153:78–91, 2014. © 2013 Wiley Periodicals, Inc.     

Nutritional Characteristics of Wild and Cultivated Foods for Chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>) in Agricultural Landscapes

Primate habitats are being transformed by human activities such as agriculture. Many wild primates include cultivated foods (crops) in their diets, calling for an improved understanding of the costs and benefits of crop feeding. We measured the macronutrient and antifeedant content of 44 wild and 21 crop foods eaten by chimpanzees (Pan troglodytes schweinfurthii) in a mosaic habitat at Bulindi, Uganda, to evaluate the common assertion that crops offer high nutritional returns compared to wild forage for primates. In addition, we analyzed 13 crops not eaten at Bulindi but that are consumed by chimpanzees elsewhere to assess whether nutritional aspects explain why chimpanzees in Bulindi ignored them. Our analysis of their wild plant diet (fruit, leaves, and pith) corresponds with previous chemical analyses of primate plant foods. Compared to wild food equivalents, crops eaten by the chimpanzees contained higher levels of digestible carbohydrates (mainly sugars) coupled with lower amounts of insoluble fiber and antifeedants. Cultivated fruits were relatively nutritious throughout the ripening process. Our data support the assumption that eating cultivated foods confers energetic advantages for primates, although crops in our sample were low in protein and lipids compared to some wild foods. We found little evidence that crops ignored by the chimpanzees were less nutritious than those that they did eat. Nonnutritional factors, e.g., similarity to wild foods, probably also influence crop selection. Whether cultivated habitats can support threatened but flexible primates such as chimpanzees in the long term hinges on local people’s willingness to share their landscape and resources with them.     

Microhabitat Variation and Its Effects on Dietary Composition and Intragroup Feeding Interactions Between Adult Female <Emphasis Type="Italic">Lemur catta</Emphasis> During the Dry Season at Beza Mahafaly Special Reserve,Southwestern Madagascar

We compared diets and female feeding agonism in 2 groups of ring-tailed lemurs living in markedly diverse microhabitats in and near the Beza Mahafaly Reserve, Madagascar during mid-to-late gestation periods and height of the dry season to test predictions concerning differences in resource availability, preferred foods, female rank, and degree and frequency of feeding agonism in relation to usurpability and monopolization of food resources. Quadrat sampling in disturbed forest habitat revealed a greater number of plant species than in the gallery forest home range area, but females in both groups consumed nearly equal numbers of actual food plant species. Higher-ranking females in disturbed forest consumed human food scraps from the researchers camp significantly more often than low-ranking females did, while there was no rank effect for consumption of any food type between females in the gallery forest group. Higher rates of female feeding agonism in both groups occurred around usurpable fruit and leaves, as well as over monopolizable human food scraps in the disturbed forest group. There is no association between degree of agonism and food type in either group, and rate of feeding agonism is similar for both groups. The most highly contested food items came in large packages and were high in nutrients: beneficial foods for gestating females in the height of dry season in southwestern Madagascar.     

Supporting conservation with biodiversity research in sub-Saharan Africa’s human-modified landscapes

Protected areas (PAs) cover 12 % of terrestrial sub-Saharan Africa. However, given the inherent inadequacies of these PAs to cater for all species in conjunction with the effects of climate change and human pressures on PAs, the future of biodiversity depends heavily on the 88 % of land that is unprotected. The study of biodiversity patterns and the processes that maintain them in human-modified landscapes can provide a valuable evidence base to support science-based policy-making that seeks to make land outside of PAs as amenable as possible for biodiversity persistence. We discuss the literature on biodiversity in sub-Saharan Africa’s human-modified landscapes as it relates to four broad ecosystem categorizations (i.e. rangelands, tropical forest, the Cape Floristic Region, and the urban and rural built environment) within which we expect similar patterns of biodiversity persistence in relation to specific human land uses and land management actions. Available research demonstrates the potential contribution of biodiversity conservation in human-modified landscapes within all four ecosystem types and goes some way towards providing general conclusions that could support policy-making. Nonetheless, conservation success in human-modified landscapes is hampered by constraints requiring further scientific investment, e.g. deficiencies in the available research, uncertainties regarding implementation strategies, and difficulties of coexisting with biodiversity. However, information currently available can and should support efforts at individual, community, provincial, national, and international levels to support biodiversity conservation in human-modified landscapes.     

Nutritional quality of gorilla diets: consequences of age,sex, and season

We tested the effects of age, sex, and season on the nutritional strategies of a group of mountain gorillas (Gorilla beringei) in the Bwindi Impenetrable National Park, Uganda. Through observations of food intake of individual gorillas and nutritional analyses of dietary components over different seasons and environments, we estimated nutrient intake and evaluated diet adequacy. Our results suggest that the nutritional costs of reproduction and growth affect nutrient intake; growing juveniles and adult females ate more food and more protein per kilogram of metabolic body mass than did silverbacks. The diets of silverback males, adult females, and juveniles contained similar concentrations of protein, fiber, and sugar, indicating that adult females and juveniles did not select higher protein foods than silverbacks but rather consumed more dry matter to ingest more protein. Juveniles consumed more minerals (Ca, P, Mg, K, Fe, Zn, Mn, Mo) per kilogram of body mass than adult females and silverback males, and juveniles consumed diets with higher concentrations of phosphorous, iron, and zinc, indicating that the foods they ate contained higher concentrations of these minerals. Seasonally, the amount of food consumed on a dry weight basis did not vary, but with increased frugivory, dietary concentrations of protein and fiber decreased and those of water-soluble carbohydrates increased. Energy intake did not change over the year. With the exception of sodium, gorillas ate diets that exceeded human nutrient requirements. A better understanding of the relative importance of food quantity and quality for different age–sex classes provides insights into the ways in which gorillas may be limited by food resources when faced with environmental heterogeneity.     

Baboon Feeding Ecology Informs the Dietary Niche of Paranthropus boisei

Hominins are generally considered eclectic omnivores like baboons, but recent isotope studies call into question the generalist status of some hominins. Paranthropus boisei and Australopithecus bahrelghazali derived 75%–80% of their tissues’ δ¹³C from C₄ sources, i.e. mainly low-quality foods like grasses and sedges. Here I consider the energetics of P. boisei and the nutritional value of C₄ foods, taking into account scaling issues between the volume of food consumed and body mass, and P. boisei’s food preference as inferred from dento-cranial morphology. Underlying the models are empirical data for Papio cynocephalus dietary ecology. Paranthropus boisei only needed to spend some 37%–42% of its daily feeding time (conservative estimate) on C₄ sources to meet 80% of its daily requirements of calories, and all its requirements for protein. The energetic requirements of 2–4 times the basal metabolic rate (BMR) common to mammals could therefore have been met within a 6-hour feeding/foraging day. The findings highlight the high nutritional yield of many C₄ foods eaten by baboons (and presumably hominins), explain the evolutionary success of P. boisei, and indicate that P. boisei was probably a generalist like other hominins. The diet proposed is consistent with the species’ derived morphology and unique microwear textures. Finally, the results highlight the importance of baboon/hominin hand in food acquisition and preparation.     

The nutritional consequences of foraging in primates: the relationship of nutrient intakes to nutrient requirements.

Many studies have examined the proportion of time that primates devote to feeding on various types of food, but relatively little is known about the intake rates associated with each food. However, the nutritional consequences of foraging can only be interpreted by comparing nutrient intakes with estimated nutrient requirements. The energy available to primates from ingested foods will depend both on the composition of the food and the extent to which various constituents, including fibre fractions, are digested. Both human and non-human primates have relatively low requirements for protein as a consequence of slow growth rates, small milk yields and relatively dilute milk. Because the nutrient demands of growth and reproduction are spread out over time, it appears that primates do not need to seek out foods of particularly high nutrient density, except perhaps during weaning. Although food selection in some species of primates appears to be correlated with the protein concentration of foods, it is unlikely that high dietary protein levels are required, at least when foods of balanced amino acid composition (such as leaves) are included in the diet.     

Nutrient composition of plants consumed by black and white ruffed lemurs,Varecia variegata,in the Betampona Natural Reserve,Madagascar

The purpose of this study was to quantify the concentrations of crude protein, fat, ash, neutral detergent fiber, acid detergent fiber, lignin, nonstructural carbohydrates, and gross energy in plant foods consumed by wild black and white ruffed lemurs (Varecia variegata). Calcium, phosphorous, magnesium, potassium, sodium, iron, zinc, copper, manganese, molybdenum, and selenium concentrations were also determined. A total of 122 samples from 33 plant families and more than 60 species were collected and analyzed for their nutritional content. The specific nutrient needs of black and white ruffed lemurs are unknown, but quantifying the nutritional composition of the foods they consume in the wild will help nutritionists and veterinarians formulate more appropriate diets for captive ruffed lemurs. This information will also supply information on how man‐induced habitat changes affect the nutritional composition of foods consumed by free‐ranging lemurs. Zoo Biol 29:375–396, 2010. © 2009 Wiley‐Liss, Inc.     

Nutrient contents predict the bamboo‐leaf‐based diet of Assamese macaques living in limestone forests of southwest Guangxi,China

Determining the nutrient factors influencing food choice provides important insight into the feeding strategy of animals, which is crucial for understanding their behavioral response to environmental changes. A bamboo‐leaf‐based diet is rare among mammals. Animals’ food choice and nutritional goals have been explained by several frameworks; however, the influence of nutrients on food choice in bamboo‐leaf‐based macaques is not yet available. Assamese macaques (Macaca assamensis) inhabiting limestone forests are characterized by such a bamboo‐leaf‐based diet, predominantly consuming young leaves of Bonia saxatilis, a shrubby, karst‐endemic bamboo. We studied the feeding behavior of one group of Assamese macaques using instantaneous scan sampling in limestone forests of the Guangxi Nonggang National Nature Reserve in southwest Guangxi, China. We compared the nutrient content of staple food and nonfood items and examine the role of key nutrients in the food selection of macaques. Our results showed that young leaves of bamboo B. saxatilis contained more water, crude protein, phosphorus, and less tannin than nonfood items. Furthermore, staple foods contained a higher content of water and less content of calcium than nonfood items. More specifically, quantities of water, crude protein, calcium, and phosphorus in food items were critical factors affecting feeding time on a specific plant item. Our results suggest that young bamboo leaves could meet macaques’ required protein and water intake, while enabling them to maintain their mineral balance, consequently facilitating to maintain the primates’ bamboo‐leaf‐diet in the limestone forest. Our findings confirm the effects of nutrient contents in food choice of Assamese macaques, highlighting the importance of the nutrient contents in maintaining their bamboo‐based diet and the need to increase the knowledge on their nutritional strategy adapted to the bamboo‐dominated diet inhabiting the unique limestone habitat.     

The Spatial Ecology of Chacma Baboons (<Emphasis Type="Italic">Papio ursinus</Emphasis>) in a Human-modified Environment

Anthropogenic habitat alteration can have a dramatic effect on the spatial distribution and ranging patterns of primates. We characterized the spatial ecology of a free-living troop of chacma baboons (Papio ursinus) in a human-modified environment in the Cape Peninsula, South Africa. We used GPS and behavioral observations collected over 1 yr to quantify the troop’s home range size, habitat selection, choice of sleeping site, and foraging patterns. The troop comprised 115 individuals living in a home range of 9.50 km², giving a density of 12.1 baboons/km². Area use correlates positively with exotic vegetation and negatively with indigenous vegetation and altitude. The troop spent significantly more time in low-lying human-modified environments, i.e., plantations, vineyards, and urban habitat, than in indigenous vegetation that was largely restricted to steeper slopes at higher elevations. The troop slept exclusively in exotic trees, 94% of which were located in the plantation, 3% in urban habitat, and 3% in vineyards. The most consumed food items were exotic grasses, subterranean food items, and exotic pine nuts. The survival and persistence of the focal troop in close proximity to the urban edge while ≥3 neighboring troops were previously extirpated suggests that access to low-lying land in conjunction with a land-use practice that does not preclude baboon presence has been fundamental to both their survival and persistence at such a high density. The almost exclusive use of exotic vegetation both as a food source and as a safe refuge for sleeping highlights the ecological flexibility of baboons, but the systematic loss of low-lying productive land poses the single greatest threat to their continued persistence on the Cape Peninsula.     

Plant foods consumed by Pan: Exploring the variation of nutritional ecology across Africa

It has been shown that differences in resource density and nutrient supply affect variation in ranging patterns, habitat use, and sociality. Among nonhuman primates, chimpanzees (Pan troglodytes) and bonobos (P. paniscus) have often been used as models for the link between social system and habitat ecology. Field reports suggest that resource density is higher in habitats occupied by bonobos (compared to chimpanzee habitats), and in the West (compared to the East) of the range of chimpanzees. In this study we compared diet quality at the level of species and populations using information from nutritional analyses of fruit and leaves consumed by chimpanzees (three) and bonobos (one population). Quality of plant foods was assessed on the basis of a) the concentration of macronutrients, fiber, and anti‐feedants, and b) associations of different nutrient components. Overall plant samples collected at each site differed in terms of macronutrient content. However, nutritious quality and gross energy content of food samples were similar suggesting that dietary quality reflects selectivity rather than habitat ecology. The quality of plant foods consumed by bonobos was within the range of chimpanzees and the quality of plant foods consumed by western chimpanzees was not higher than that of eastern chimpanzees. While the results showed significant variation across forests inhabited by Pan, they did not match with geographical patterns between and within Pan species as proposed in previous studies. This suggests that the nutritional quality of the habitat is not always a reliable predictor of the quality of the diet. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.     

Nutritional composition of the diet of the western gorilla (Gorilla gorilla): Interspecific variation in diet quality

To meet nutritional needs, primates adjust their diets in response to local habitat differences, though whether these dietary modifications translate to changes in dietary nutrient intake is unknown. A previous study of two populations of the mountain gorilla (MG: Gorilla beringei) found no evidence for intraspecific variation in the nutrient composition of their diets, despite ecological and dietary differences between sites. One potential explanation is that nutritional variability in primate diets requires greater ecological divergence than what was captured between MG sites, underpinning environmental differences in the nutrient quality of plant foods. To test whether Gorilla exhibits interspecific variation in dietary composition and nutrient intake, we studied the composition and macronutrients of the western gorilla (WG: Gorilla gorilla) staple diets and compared them with published data from the two MG populations. We recorded feeding time and food intake of four adult female WGs from one habituated group over a period of 11 months (December 2004–October 2005) at the Mondika Research Center, Republic of Congo, allowing for assessment of seasonal patterns of nutrient intake. Staple diets of WGs and MGs diverged in their dietary and macronutrient composition. Compared to MGs, the staple diet of WGs (by intake) contained higher proportions of fruit (43%) and leaf (12%) and a lower proportion of herb (39%), resulting in a higher intake of total nonstructural carbohydrate and fiber and a lower intake of crude protein. Staple gorilla fruits and herbs differed in nutrient quality between sites. Gorillas exhibit nutritional flexibility that reflects ecological variation in the nutrient quality of plant foods. Since dietary quality typically affects rates of growth and reproduction in primates, our results suggest that interspecific differences in nutrient intake and food quality may shape differences in gorilla nutrient balancing and female life history strategies.