Diet traditions in wild orangutans

This study explores diet differences between two populations of wild Bornean orangutans (Pongo pygmaeus wurmbii) to assess whether a signal of social learning can be detected in the observed patterns. The populations live in close proximity and in similar habitats but are separated by a river barrier that is impassable to orangutans in the study region. We found a 60% between‐site difference in diet at the level of plant food items (plant species–organ combinations). We also found that individuals at the same site were more likely to eat the same food items than expected by chance. These results suggest the presence of diet (food selection) traditions. Detailed tests of three predictions of three models of diet acquisition allowed us to reject a model based on exclusive social learning but could not clearly distinguish between the remaining two models: one positing individual exploration and learning of food item selection and the other one positing preferential social learning followed by individual fine tuning. We know that maturing orangutans acquire their initial diet through social learning and then supplement it by years of low‐level, individual sampling. We, therefore, conclude that the preferential social learning model produces the best fit to the geographic patterns observed in this study. However, the very same taxa that socially acquire their diets as infants and show evidence for innovation‐based traditions in the wild paradoxically may have diets that are not easily distinguished from those acquired exclusively through individual learning. Am J Phys Anthropol 143:175–187, 2010. © 2010 Wiley‐Liss, Inc.     

Patterns of molar wear in hunger-gatherers and agriculturalists

Tooth wear records valuable information on diet and methods of food preparation in prehistoric populations or extinct species. In this study, samples of modern and prehistoric hunger-gatherers and agriculturalists are used to test the hypothesis that there are systematic differences in patterns of tooth wear related to major differences in subsistence and food preparation. Flatness of molar wear is compared for five groups in hunger-gatherers (N = 298) and five groups of early agriculturalists (N = 365). Hunger-gatherers are predicted to develop flatter molar wear due to the mastication of tough and fibrous foods, whereas agriculturalists should develop oblique molar wear due to an increase in the proportion of ground and prepared food in the diet. A method is presented for the quantitative measurement and analysis of flatness of molar wear. Comparisons of wear plane angle are made between teeth matched for the same stage of occlusal surface wear, thus standardizing all groups to the same rate of wear. Agriculturalists develop highly angled occlusal wear planes on the entire molar dentition. Their wear plane angles tend to exceed hunger-gatherers by about 10 degrees in advanced wear. Wear plane angles are similar within subsistence divisions despite regional differences in particular foods. This approach can be used to provide supporting evidence of change in human subsistence and to test dietary hypotheses in hominoid evolution.     

Flexible and conservative features of social systems in tufted capuchin monkeys: comparing the socioecology of Sapajus libidinosus and Sapajus nigritus

Socioecological models assume that primates adapt their social behavior to ecological conditions, and predict that food availability and distribution, predation risk and risk of infanticide by males affect patterns of social organization, social structure and mating system of primates. However, adaptability and variation of social behavior may be constrained by conservative adaptations and by phylogenetic inertia. The comparative study of closely related species can help to identify the relative contribution of ecological and of genetic determinants to primate social systems. We compared ecological features and social behavior of two species of the genus Sapajus, S. nigritus in Carlos Botelho State Park, an area of Atlantic Forest in S?o Paulo state, and S. libidinosus in Fazenda Boa Vista, a semi-arid habitat in Piauí state, Brazil. S. libidinosus perceived higher predation risk and fed on clumped, high quality, and usurpable resources (fruits) all year round, whereas S. nigritus perceived lower predation risk and relied on evenly distributed, low-quality food sources (leaves) during periods of fruit shortage. As predicted by socioecology models, S. libidinosus females were philopatric and established linear and stable dominance hierarchies, coalitions, and grooming relationships. S. nigritus females competed less often, and could transfer between groups, which might explain the lack of coalitions and grooming bonds among them. Both populations presented similar group size and composition and the same polygynous mating system. The species differed from each other in accordance with differences in the characteristics of their main food sources, as predicted by socioecological models, suggesting that phylogenetic inertia does not constrain social relationships established among female Sapajus. The similarity in mating systems indicates that this element of the social system is not affected by ecological variables and thus, is a more conservative behavioral feature of the genus Sapajus.     

Early dry season subsistence ecology of Cuiva (Hiwi) foragers of Venezuela

The subsistence ecology of Venezuelan Cuiva foragers during the early dry season is described. Data on diet, time allocation, demography, and physical measurements are presented. Analyses show that the Cuiva depend primarily on game and wild roots during the early dry season for their subsistence. Sex differentials in productive efficiency, total contribution to the diet, and time allocation to food acquisition and other activities are also examined. As in most other foraging societies, men specialize in hunting while women specialize in gathering. During the early dry season, men provide more calories than women and are the more efficient food producers. However, men spend slightly less time than women in food acquisition. Demographic data show that child mortality rates, female infertility rates, female infanticide rates,and the sex ratio among juveniles are high in the Cuiva population. Comparisons between the patterns found among the Cuiva and other foraging populations are made.     

Research on the Efe and Lese populations of the Ituri forest,Zaire

Since 1980, as part of the Ituri Project, researchers have been studying numerous aspects of the biology, health, economy, and social relations of Efe (Pygmies) and Lese villagers living in the Ituri Forest region of north-eastern Zaire. The Efe are seminomadic people who hunt and gather forest resources for their own consumption and for exchange with sedentary subsistence farmers. The Lese are Sudanic-speaking subsistence farmers who practice shifting slash-and-burn horticulture and live in semipermanent villages. Relations between the Efe and Lese have been close for many generations and extend beyond economic exchange to include most aspects of ritual and social life. This paper serves as an introduction to five subsequent papers that report findings from research on these two forest-living populations. It provides background information concerning the ecology and history of human occupation of the Ituri region of central Africa; it describes the study area and the study populations; it discusses how the annual subsistence cycles of the Efe and Lese relate to rainfall and food availability; and it provides further information concerning Ituri Project research during the last 7 years.     

Socioecological factors influencing population structure of gorillas and chimpanzees

Differences in distribution and density between gorillas and chimpanzees are reconsidered with special reference to population structure. Both ecological and social factors influencing population structure are compared between species and between habitats within species. Gorillas and chimpanzees respond differently to a decline in food quality, such as fruit scarcity: gorillas change diet and decrease range, while chimpanzees do not change diet but may expand range. These responses result in different effects on their grouping patterns. For gorillas the dispersed distribution and reduction of range size decreases the rate of inter-unit encounters and female transfer. The concentration of social units increases the rate of aggressive contact between units and stimulates female transfer. Social units of gorillas may crowd or disperse in order to attain the optimal density. This tendency may result in similar densities of gorillas across habitats. By contrast, the distribution patterns or range size may not affect inter-unit relationships of chimpanzees. Within a single unit-group, various reproductive strategies are adopted by both sexes. Independent travel of females and flexible grouping patterns enable them to survive at very low density in extraordinary large ranges. Density and inter-unit relationships are good criteria for a healthy population of gorillas, while the size of unit-group and inter-individual relationships are good criteria for chimpanzees. Conservation planners should consider these differences for sympatric and allopatric survival in these species.     

Revisiting the food component of the ecological footprint indicator for autonomous rural settlement models in Central Italy

The aim of this work is to design a model of sustainable rural settlement to ensure food self-sufficiency. The strategic objective of this study is to verify how the development of rural settlements based on this model contributes to overall sustainability. The sustainability assessment is based on an ecological footprint indicator introduced by Rees (1992) and developed by Rees and Wackernagel (1994).The operational objective of this work is to develop an ecological footprint of autonomous food systems model that is able to determine the land area needed to ensure the food self-sufficiency of an Italian settlement while varying the number of components and the diet followed. The model is also intended to determine the food component of the ecological footprint indicator.Model development started with the identification of the average diet for a community, which was determined from organic farming criteria, crop layouts and livestock farming characteristics necessary to meet demand. The research demonstrated that by promoting food self-sufficient rural settlements, the food component of the ecological footprint indicator is lowered by 47.32% compared to the national average and by 8.11% compared to the world average.The development of this model has also highlighted how the ecological footprint indicator is not valid for assessing the autonomous sustainability of a community, leading to a systematic underestimation of humanity's true impact.     

Varietal mixtures: a viable strategy for sustainable productivity in subsistence agriculture

Remarkable parallels link the development of varietal mixtures across subsistence farming systems. Mixtures are grown and persist because they prolong harvest and income flow and provide diversity of diet. From our review of research on agronomic and disease aspects of mixtures in modern agriculture, it is also clear that improved stability and decreased disease severity are common features of mixtures relative to their components in monoculture. Such advantages are of value to both modern and subsistence agriculture. However, in the majority of cases, the yield advantage of mixtures is small. Overall, we conclude that varietal mixtures are presently a viable strategy for sustainable productivity in subsistence agriculture, have potential for improvement without sacrifice of diversity, are an important resource for future global food production and may have an expanding role in modern agriculture in situations where qualitative uniformity is not the guiding priority.     

Spectrographic analysis of trace elements in archaeological skeletal material from Florida: a preliminary report

Technological advances have resulted in the development of an additional approach to determining the dietary practices of prehistoric populations. Bones are known to retain certain trace elements, the analysis of which should yield valuable clues to subsistence. Since there has never been a study of this nature attempted on Indian remains in Florida, a qualitative trace element analysis, using an optical emission spectrograph, was made of bone samples from indigenous populations representing both inland and coastal environments in this region. Results of this study showed that magnesium was present in all samples, copper was present in nearly half the samples, and manganese and zinc were not detected. Thus, although the diets of these groups may have varied, the trace element content did not reflect significant differences as have been reported for other types of analyses on Indian populations from diverse geographic regions.     

Buccal dental microwear variability in extant African Hominoidea: taxonomy versus ecology

Buccal microwear patterns on teeth are good indicators of the abrasiveness of foodstuffs and have been used to trace the dietary habits of fossil species, including primates and hominids. However, few studies have addressed the variability of this microwear. The abrasiveness of dietary components depends not only on the hardness of the particles ingested, but also on the presence of dust and other exogenous elements introduced during food processing. These elements are responsible for the microwear typology observed on the enamel surfaces of primate teeth. Here we analyzed the variability of buccal microwear patterns in African Great Apes (Gorilla gorilla and Pan troglodytes), using tooth molds obtained from the original specimens held in several osteological collections. Our results suggest that ecological adaptations at subspecies or population level account for differences in microwear patterns, which are attributed to habitat and ecological conditions within populations rather than differences between species. The findings from studies on the variability of buccal dental microwear in extant species will contribute to a better understanding of extinct hominids’ diet and ecology.     

Ecology of gorillas and its relation to female transfer in mountain gorillas

Understanding the principles that underly primate social evolution depends on integrated analysis of data on behavioral ecology, demography, life history tactics, and social organization. In this paper, data on the behavioral ecology of gorillas are reviewed and comparisons made among the three subspecies. Gorillas are selective feeders; and, their patterns of food choice are consistent with models of feeding by large generalist herbivores. They rely heavily on terrestrial herbaceous vegetation, which provides an abundant supply of densely distributed food. Availability of this food varies little in space and time; and, gorilla foraging activity can maintain its productivity. The level of frugivory and the extent of seasonal variation in diet and habitat use vary among and within populations. Low variability in food distribution patterns makes cooperative defense of foraging areas not worthwhile; but, it also means that ecological costs associated with gregariousness are low. However, demographic and life history data on mountain gorillas show that these costs may be sufficient to reduce female reproductive success as group size increases. Advantages to being with high quality males apparently can outweigh these costs. The implications of these data for the evolution of the mountain gorilla social system, and the possible roles of male protection, predation, and female/female competition in this regard, are discussed.     

The ecology and evolution of tooth wear in red deer and moose

Differences in body size and diet type (browser–grazer continuum) have formed functional traits of ruminants, including tooth design. Grazers and mixed-feeders eat a more fibrous diet than browsers, which arguably increase tooth wear. Tooth wear has also been suggested to increase with body size. Moreover, for species with large distribution ranges, different populations may be exposed to very different ecological factors affecting diet and thus tooth wear rates. Therefore, evolutionary history and contemporary ecological conditions, both operating through diet, may be important for patterns of tooth wear. Here, we compare inter- and intraspecific rates of tooth wear in multiple populations of one large browser (moose Alces alces ) and one mixed-feeder (red deer Cervus elaphus ) covering the main distribution range of each species in Norway. We found that the mixed-feeding red deer wore teeth faster than the larger and browsing moose, suggesting that feeding-type was more important than body size for patterns of wear. There was substantial spatial variation in tooth wear rates, but the inter-specific difference in wear was consistent. Molar wear rates, but not incisors wear rates, in the browser were less variable between populations than in the mixed-feeder. There was no close link between incisor and molar wear rates at the population level. Our findings are consistent with the view that both evolution related to diet type and current ecological conditions (being proxies for within-species variation in diet quality) are important for patterns of tooth wear.     

Latency in response of barn swallow Hirundo rustica populations to changes in breeding habitat conditions

Inclusion of past, in addition to current ecological conditions can improve the realism of animal‐habitat models, because populations may show delayed responses to changing environments. We studied the relationships between the distribution of barn swallows (Hirundo rustica L.) in 2001 and ecological factors between 1986 and 2001. Livestock farming was the best predictor of swallow distribution. Maximum predictive power of swallow abundance was achieved by livestock farming data 7 years before the census and significantly earlier than 2001, as shown by a bootstrap analysis. Breeding philopatry, social facilitation of breeding habitat choice may delay response of barn swallow populations to rapidly changing ecological conditions in anthropogenic habitats. By bootstrapping the set of farms and applying our predictive distribution models to livestock farming data in the past and those predicted for the near future we forecast no significant change in swallow populations until 2015. This study suggests that population studies should incorporate historical ecological data.     

Wildlife farming: an alternative to unsustainable hunting and deforestation in Neotropical forests?

Wild animals have been a source of food and income through subsistence hunting by forest-dwelling people in Neotropical countries in spite of the fact that hunting appears to be unsustainable as it leads to the depletion of wild fauna. Laws in Brazil and other Latin American countries forbid hunting but allow the commercial use of captive-bred animals. Notwithstanding the fact that this is a controversial topic among conservationists, in this paper we propose that wildlife farming in the Neotropics can be an alternative to the over-hunting and deforestation that are carried out for the production of traditional food and pastures for livestock. This review sets out this proposal, and discusses the implications for tropical forest integrity and rural population dependency on forest resources. We discuss the ecological and economical advantages of wildlife farming and its constraints as a conservation tool, using collared peccary (Pecari tajacu) farming in the Amazon region as a model. Productivity levels may reach 19,000 times higher than those obtained from the management of peccaries from forests in the Amazon region. This can be achieved with an easily obtainable diet composed of forest fruits and locally available agricultural by-products. Therefore, establishing captive management programs for peccaries is an effective way of avoiding wild stock depletion, deforestation, and guaranteeing the livelihood of forest dwellers in the Neotropics. However, it is essential that governmental and/or non-governmental agencies be involved in providing subsides to establish peccary farms, provide technical assistance, and introducing peccary captive breeding centers to supply founder stock.     

Biosocial responses to seasonal food stress in highland Peru

This paper examines patterns of seasonal variation in food consumption and responses to food stress in the highland community of Nu?oa, Peru. Dietary and anthropometric data collected from January through August of 1985 on a sample of 26 households (127 individuals) are analyzed. This study finds sharp seasonal differences in energy intake (pre-harvest = 1150 calories/day; post-harvest = 1519/day; p less than 0.01) associated with variation in the availability of locally-produced products (e.g., tubers and cereals). Seasonal energy reduction, however, does not uniformly affect all sectors of this population. Children experience little seasonal change in energy intake and have a more adequate pre-harvest diet and better nutritional status than adults. The responses used to "protect" children from energy stress and minimize the overall impact of seasonal food scarcity on this community include: 1) reduction of pre-harvest household caloric needs through emigration of adolescent and adult males, 2) preferential allocation of food to children during the pre-harvest period, 3) seasonal reduction of activity levels and the year-round use of children for many productive activities, and 4) seasonal changes in meal patterns that minimize post-prandial energy loss during periods of stress. Evaluation of similar data from other anthropological populations underscores the diversity of responses to seasonal change in food availability. Moreover, these data indicate that the protection of children from seasonal energy stress is more common than previously thought. Variation in adaptive responses to food stress appears to be dependent upon 1) the nature of the subsistence economy, 2) the relative contributions of children and adults to household production, and 3) the demographic structure of the population.     

Chromium is not an essential trace element for mammals: effects of a “low-chromium�?diet

Chromium was proposed to be an essential trace element over 50?years ago and has been accepted as an essential element for over 30?years. However, the studies on which chromium’s status are based are methodologically flawed. Whether chromium is an essential element has been examined for the first time in carefully controlled metal-free conditions using a series of purified diets containing various chromium contents. Male Zucker lean rats were housed in specially designed metal-free cages for 6?months and fed the AIN-93G diet with no added chromium in the mineral mix component of the diet, the standard AIN-93G diet, the standard AIN-93G diet supplemented with 200?μg?Cr/kg, or the standard AIN-93G diet supplemented with 1,000?μg?Cr/kg. The chromium content of the diet had no effect on body mass or food intake. Similarly, the chromium content of the diet had no effect on glucose levels in glucose tolerance or insulin tolerance tests. However, a distinct trend toward lower insulin levels under the curve after a glucose challenge was observed with increasing chromium content in the diet; rats on the supplemented AIN-93G diets had significantly lower areas (P?<?0.05) than rats on the low-chromium diet. The studies reveal that a diet with as little chromium as reasonably possible had no effect on body composition, glucose metabolism, or insulin sensitivity compared with a chromium-“sufficient??diet. Together with the results of other recent studies, these results clearly indicate that chromium can no longer be considered an essential element.     

Feeding Competition and Agonistic Relationships Among Bwindi <Emphasis Type="Italic">Gorilla beringei</Emphasis>

Testing predictions of socioecological models, specifically that the types of feeding competition and social relationships female primates exhibit are strongly influenced by the distribution, density, and quality of food resources, requires studies of closely related populations of subjects living under different ecological conditions. I examined feeding competition and the resulting female social relationships in mountain gorillas (Gorilla beringei beringei) of Bwindi Impenetrable National Park, Uganda, which has ecological conditions distinctive from those where other gorilla populations live. I observed 1 group of gorillas for 29 mo to examine the proportion of time spent foraging on fruit, the relationship between patch size and occupancy patterns of fruit trees, and agonistic interactions. Patch occupancy time while foraging in fruit trees decreased with increasing number of gorillas in a tree and decreasing tree size, suggesting that fruit trees represent limiting patches and can lead to intragroup scramble competition. Gorillas exhibited higher levels of aggression while feeding on fruit versus other food resources, which indicates intragroup contest competition. I observed a linear dominance hierarchy with no bidirectionality via displacements, and a similar hierarchy via aggression, though a notable proportion of the dyads contained 2-way interactions. However, most aggression was of low intensity (vocalizations) and the recipient typically ignored it. Despite differences in ecological conditions and diet between the Virunga Volcanoes and Bwindi, agonistic relationships among females are largely similar in the 2 populations and are best characterized as dispersal individualistic.     

The Social Behavior of Brown Spider Monkeys (Ateles hybridus) in a Fragmented Forest in Colombia

Forest fragmentation and habitat loss are two of the main drivers of wildlife population declines. Animals exposed to habitat disturbances must develop behavioral strategies to adapt to novel, rapidly fluctuating socioecological challenges. Understanding the behavioral flexibility of endangered primates as a response to ecological challenges, e.g., anthropogenic habitat disturbance, is a key element in the design of successful conservation initiatives for remaining populations. We studied the social behavior of a group of 11 adult and subadult brown spider monkeys (Ateles hybridus) living in a recently isolated and densely populated forest fragment in the Magdalena River Valley, Colombia, and compared their behavior to that of other wild spider monkey populations. From June 2009 to July 2010 we assessed diet, activity budgets, and the rates of affiliative and agonistic interactions initiated and received by adult male and female spider monkeys. The diet of our focal group was quite different from that in most previous studies of Ateles: leaves accounted for ca. 40?% of their diet, and fruits represented barely half of their diet, suggesting that this population has had to adjust its feeding strategies to the local ecological challenges. We found no sex differences in the time males and females spent resting, moving, and socializing, but females tended to invest more time in feeding than males did. Male-to-female aggression was the most common agonistic interaction, and same-sex aggressions were almost absent. We found no significant differences in rates of grooming or embracing between the different types of dyads. The resemblance of our results to those of similar studies in less disturbed habitats suggests that spider monkeys might adapt to certain levels of ecological and social disturbance, at least initially, and are a starting point to understand better the initial effects of fragmentation on the behavioral repertoire of these primates.     

Viliui Sakha Post-Soviet Adaptation: A Subarctic Test of Netting's Smallholder—Householder Theory

The Sakha of northeastern Siberia, Russia, are the highest latitude contemporary agropastoralists practicing horse and cattle husbandry. In the last 100 years their rural livelihood has gone from household-level subsistence food production in clan clusters of single-family homesteads scattered across the landscape, to village-level state agribusiness farm production in compact settlements dependent on Soviet socialist infrastructure, to the present-day post-socialist reliance on household-level subsistence food production. This paper explores how Viliui Sakha are adapting in the post-Soviet context. Since the fall of the Soviet Union and the concomitant dissolution of the centralized state farm system, rural inhabitants have developed household and interhousehold food production capacities based on keeping cows and relying on exchange among kin. One of the basic tenets of Robert Netting's smallholder–householder theory is that in times of change, the household system is the most resilient subsistence production unit because of specific qualities including intimate ecological knowledge and implicit labor contracts. This research shows in what ways Netting's householder theory applies for subarctic agropastoralists.