Historical trends in forager and farmer exchange in the Ituri rain forest of northeastern Zaïre

Using oral histories, archival materials, and observations of present behavior, a largely hypothetical historical reconstruction of the natural resource exploitation and subsistence practices of Lese farmers and Efe foragers in the Ituri Forest of northeastern Zaïre is presented. Distinct epochs associated with the advent of forest agriculture, Belgian colonization, and post-independence economic collapse have resulted in changes in local population density, the range of forest resources exploited, and the spatial distribution and intensity of resource use. Broadly speaking, there has been a historical trend toward sedentism, spatial clumping of settlements, localization of resource exploitation, reduced importance of forest carbohydrates in the diet, and an increased reliance on agricultural products. Over time the Efe and Lese exchange system has changed, in relation to the items traded and the relative dependence of each partner on the exchange relationship. Involvement in this alliance has had a considerable impact on Efe settlement pattern, diet, and probably fecundity. It ultimately placed the Lese in a position of power over the Efe, and provided the farmers with means to enter a transient monetary economy. By providing a retrospective on Efe and Lese subsistence, we hope to demonstrate that to decipher the relative benefits and constraints of this contemporary exchange relationship, we must understand their historical etiology.     

Anomalously low endemic goiter prevalence among Efe pygmies

The existence of endemic goiter, caused by iodine deficiency and the presence of a dietary goitrogen, has been noted in eastern Zaire by a number of authors (De Visscher et al.: Journal of Clinical Endocrinology and Metabolism 21:175-188, 1961; Delange et al.: Journal of Clinical Endocrinology and Metabolism 34:1059, 1972). In the Ituri Forest of Huate-Zaire, two distinct populations, the Efe (pygmy) and Lese (Bantu), live in association with each other and have similar diets. The goiter survey reported here documents differences in goiter prevalence and severity between the nomadic pygmy and village-living Bantu populations. While the Efe have an overall goiter prevalence of 9.4%, the Lese have a goiter prevalence of 42.9%. Furthermore, Efe women living in Lese villages and subsisting on a Lese diet have a prevalence of goiter similar to that of forest-living Efe women. Village-living individuals born of Efe mothers and Lese fathers have a prevalence of goiter greater than that of pure Efe but less than that of Lese. While our data cannot exclude dietary explanations for the difference in goiter prevalence between the Efe and Lese, they do support the hypothesis that the Efe possess an adaptation to an iodine-deficient environment that does not result in the development of goiters.     

Fitness and Oxygen uptake of children in the Ituri forest. Natural selection or adaptation to the environment?

For the inhavitants of an isolated niche like the Ituri rain forest of N-E Zaire, the interplay of natural selection and conditioning by daily physical activity should influence the physical development of growing children, provided general health and nutrition stay within acceptable limits. The general health of 389 children between 5 and 15 years of age (207 Lese villagers and 182 Efe Pygmies) living in that area, appears to be fairly good, although the hematocrite is low (37 and 34% respectively). Tuberculine reaction is positive in over 50%, intestinal parasites generally present while more than 50% are free of dental caries. Efe children stand peristently some 10 cm smaller and weigh 5 to 6 kg less than Lese of the same age, who reach only the 3rd percentile of European children (Tanner-Whithouse 1963). In the motorfitness, Efe score better than Lese for balance and flexibility tests. Both appear superior to European children of the same age, they are equal or better for strength, even when adjusted for body size. Against this background, the Oxygen uptake (VO₂) at increasing work load on the step test of 58 Lese and 56 Efe indicates similar efficiency. The Efe reach a fixed VO₂ with higher Heart Rate (HR), which is consistent with their smaller size, hence smaller heart and stroke volume. The difference disappears when adjusted for body size. Children living in the Ituri forest tend to be fitter than Europeans notwithstanding their health condition. This belies any Energy Proteine Malnutrition (EPM) form earky childhood on, and supports the thesis that the small body size of the Efe follows genetic factors and does not result from poor health or chronic EPM in childhood.     

Nutritional status of Efe pygmies and Lese horticulturists

We assessed the nutritional status of 90 pygmies (Efe) and 211 members of a neighboring horticultural Lese in the Ituri forest in northeast Zaire. Clinical signs of iron and iodine deficiency were highly prevalent, but the frequency of these and other clinical signs of nutritional deficiency did not differ between the two groups. Infectious diseases such as yaws, cellulitis, and filiariasis were common. Absolute heights and weights of both Efe males and females aged 2–18 years were less than the 5th percentile of the National Center for Health Statistics standards. Weights for height of both groups were within the normal range. Weights and heights, expressed as percentages of the 50th percentile for age and sex, were significantly lower (P < .001) in Efe males and females than among Lese males and females, but weights for height did not differ significantly. Z-Scores of height and weight were also significantly lower in Efe males and females than among their Lese counterparts. The differences in weight and height, expressed either as a percentage of the 50th percentile or as Z-scores, were most apparent in older adolescents and persisted among adults. The normal weight for height among both populations indicated that acute undernutrition did not exist at the time of the survey. Despite comparable levels of adult fatness, measured by triceps skinfold thickness, heights of Efe males and females were lower than those of the Lese. These observations support the hypothesis that genetic differences account for the short stature of the Ituri pygmy. However, because the environments shared by the two groups are not identical and because other practices differ, nutritional effects cannot be excluded.     

The ecology of birth seasonality among agriculturalists in central Africa.

The Lese are subsistence farmers living in the Ituri Forest of north-east Za?re. They exhibit significant birth seasonality, with lowest frequencies of conception when food production is least, nutritional status is low and ovarian function, as measured by salivary steroid hormone levels, is reduced. Efe pygmy foragers, who live in the same geographical area but are less dependent on cultivated foods and have a more flexible life style, do not exhibit frequent fluctuations in nutritional status nor significant birth seasonality. These findings support a model of birth seasonality relating climatic variables to variation in fertility through a causal chain linking rainfall to food production to energy balance to ovarian function to fertility. The model, which emphasises an ecological approach to the study of human reproduction, should have broad applicability since seasonality of food production and energy balance is widespread geographically and across a wide variety of economies and cultures.     

Ecology and affective behavior: selected results from a quantitative study among Efe foragers of northeast Zaire

This paper reports selected results of a quantitative study of the affective behavior of the Efe, exchange-dependent hunter-gatherers of the Ituri forest in northeastern Zaire. Measures of the amount and kind of affective display were based on systematic, direct observation of the routine behavior of three Efe bands in residential settings (camps), using a new technique to characterize affect-laden behavior according to nonlinguistic information conveyed in the voice. Resulting data provide a direct measure of the affective milieu of a foraging people, providing an objective indicator of the subjective impact of social and ecological conditions, which are thought to affect quality of life. In this paper, measures of "camp mood" are used to explore the psychosocial impact of a 3-month period of acute food shortage that occurred in the Ituri Project study area in 1983. Contrary to expectation, rates of behaviors conveying pleasure did not exhibit significant change, whereas a 44% increase in expressions of displeasure and a 17% drop in use of complaint tones were observed during the period of hunger. This and other findings support the view that systematic, direct observation in natural habitats can increase our understanding, both of the functions of affective behavior, and of the affective dimension of quality of life.     

Net hunters vs. archers: Variation in women's subsistence strategies in the Ituri Forest

BaMbuti of the Ituri Forest, Zaire, employ two primary hunting techniques: net hunting, in which women routinely participate, and bow hunting, in which women rarely participate. We hypothesize that the value of women's labor devoted to different subsistence activities, combined with the exchange value of meat, will determine whether women participate in hunts. Field observations were conducted in four different areas: two exploited by archers and two by net hunters. Results indicate that women in nethunting areas earn more calories per unit time by hunting than by working in agriculturalists' gardens; whereas women in archer areas earn more calories by working for agriculturalists than by hunting. We found no significant difference in the composition or diversity of the forests exploited by net hunters and archers. The results are discussed in light of the longstanding debate concerning the factors that account for distribution of net hunting and archery in the Ituri Forest.     

Ecology and ovarian function among Lese women of the Ituri Forest, Zaire

Ovarian function is examined in 35 Lese women inhabiting the Ituri Forest of northeastern Zaire over a period of 4 months through measurements of progesterone in saliva samples collected twice weekly. Ovulatory frequency is found to be only 56% on average, with a pattern of age variation similar to that observed in western women, though lower in level at each age. Average luteal progesterone levels of the Lese women are lower than those of Boston controls even if only ovulatory cycles are considered. Women with the poorest nutritional status, inferred from longitudinal weight changes and weight for height, show the greatest compromise of ovarian function, and the average ovulatory frequency of the whole sample declines in parallel with a period of weight loss over four months. It is suggested that low ovulatory frequency and luteal insufficiency contribute to the low fecundity of the Lese population and that nutritional status is likely to be one of the ecological factors modulating this effect.     

Significance of the social relationships of Efe Pygmy men in the Ituri forest,Zaire

Efe Pygmies in northeast Zaire exhibit features of social organization (small group size, flexible but predominantly patrilocal residence, close relations with kin, and pair bonds) that are common to many hunting and gathering societies. This study uses methods commonly employed in studies of nonhuman primates to investigate the associations of Efe men with other individuals as a function of their age, sex, and kinship, and it tests the hypothesis that Efe are patrilocal because hunting efficiency is improved by hunting with male relatives. The analyses of 376 hours of focal behavior observations on 16 Efe men and observations of 71 cooperative group hunts show that the majority of associations between Efe men were with other adult men. Men associated preferentially with kin over nonkin, and they associated with close kin more than with distant kin. Men's close relationships (what we call “Companionships” sensu Smuts' “Friendships” in baboons) were predominantly with other adult men, but each man who cohabited with a woman had his strongest Companionship by far with that woman. Neither the efficiency of hunts nor the hunting success of individual men were found to be related to the degree of relatedness of hunters nor the proportion of relatives on the hunt. Alternative hypotheses concerning the functional significance of patrilocality and male kin groups are considered. We conclude that strong affiliative bonds between male kin and between males and females may arise as much from the need for strong allies in the face of competitive social situations as from economic or ecological necessity.     

Salivary progesterone and luteal function in two low-fertility populations of Northeast Zaire

30 Ituri women (Zaire) -- 14 Efe and 16 Balese -- were targeted as subjects in this study designed to verify that, under field conditions, the salivary steroid method can reliably discern follicular and luteal levels of progesterone in normal menstrual cycles and to examine the hypothesis that infertility among these women is due to tubal factors. Findings of normal ovulatory function in fertile women would support the hypothesis; findings of abnormal gonadal function might either indicate a chronic endocrine imbalance or the short-term effects of nutritional and other stressors. All potential subjects ranged in age between 20-35 years, were involved in stable conjugal unions, had no nursing children, and reported either no births or none within the last 6 years. 25 women completed the study. The Boston field control subjects consisted of 18 volunteers ranging in age between 18-43 years. All reported a history of regular menstrual cycles and were nither using oral steroid contraceptives nor engaged in a regular exercise program. The African women had significantly lower luteal progesterone levels than did the Boston controls. Additionally, a significantly higher proportion of the African women failed to demonstrate clear luteal activity, suggesting that a higher rate of anovulation contributed to the low average luteal progesterone levels. The composite-cross-sectional profile for the Ituri Forest women suggests that the average luteal phase for this group was shorter than for the Boston controls. Further investigations need to determine whether gonadal dysfunction such as observed in this study is a regular feature of the reproductive physiology of women in the Ituri Forest, or whether it emerges only in periods of food shortage and significant weight loss. Gonorrhea may be the major cause of infertility in the Ituri region, but it is likely that other factors directly affecting gonadal function contributed to the observed pattern of low fertility. Clearly, the study illustrates the potential usefulness of salivary steroid assays.     

Primate subsistence patterns: Collector-predators and gatherer-hunters

Hominization via predation has become a pervasive anthropological theme in recent years. Indeed, the assumption that hunting behavior originated within the primate phylogenetic sequence as a “human” subsistence pattern has generated numerous subsidiary hypotheses about how secondary traits were initiated, propagated or enhanced when a terrestrial, savanna-dwelling, meat-eating hominid line emerged from an arboreal, forest-dwelling, plant-eating ancestral stock. New field evidence on the behavioral and organizational features of subsistence in nonhuman and human primates now provides the basis for reconsidering these views.Many monkey, ape and human populations no longer seem to fit the stereotyped images sketched in past decades, when little or no comparative information was available to anthropologists. The discrepancy between the old concepts and new facts is particularly evident in Sub-Saharan Africa, where numerous primate taxa have been studied in climatically and biotically similar zones. In this region alone, more than 364 cases of predation, involving 22 different species of mammalian prey, have been recorded among at least 10 supposedly “vegetarian” baboon and chimpanzee populations dispersed between Ethiopia and South Africa. Furthermore, many of the human populations living within this same region—such as the Mbuti pygmies, the Hadza and the Kalahari bushmen—have been characterized as “hunters” but actually subsist for the most part on foods other than meat. These basic facts about collector-predator and Gatherer-hunter subsistence patterns are a mere beginning, however, for popular conceptions of primate lifestyles are eroding swiftly along many axes of investigation. It is becoming clear, for instance, that many primates—from prosimians to humans—are actually omnivores even though anthropologists have persistently miscast them as frugivores or carnivores. This false dichotomization of nonhuman versus human diets has led to a series of equally erroneous dichotomies in nonhuman versus human behavior. Thus, the possession of culture, technology, language and other similarly amorphous traits, many of which were in fact derived from this presumed shift in subsistence, have become entrenched as concepts of human uniqueness. In recent years, however, many new discoveries in primatology, and in ethnography and archeology, have weakened the theoretical structure to which “man-the-hunter” has been pinned. It is probable that savanna-dwelling, tool-using, seed-eating, scavenging and other independent schemes can now be replaced by a single, much simpler model wherein subsistence shifts among both nonhuman and human primates are perceived as smooth transitions within a graded continuum of evolution. Thus, the central objective of this report is to show that the subsistence activities of several extant cercopithecid, pongid and hominid populations in Africa can be arranged along an integrated spectrum which reflects gradual processes in the evolution of primate behavior and organization. This spectrum serves as the crux for a unifying model of behavioral evolution, and can in turn be broken down into a linked series of subsidiary models which elucidate specific aspects of primate prehistory.     

Testosterone levels among Aché hunter-gatherer men

Salivary testosterone levels were measured in a population of New World indigenous adult hunter-gatherer males in order to compare circulating levels of free unbound bioactive steroid with those previously reported among Boston and nonwestern males. The study population consisted of adult Aché hunter-gatherer males (n=45) living in eastern Paraguay. Morning and evening salivary testosterone levels (TsalA.M.; TsalP.M.) among the Aché were considerably lower than western values (Boston) and even lower than other previously reported nonwestern populations (Efe, Lese, Nepalese). No association was observed between height, weight, or age and salivary testosterone levels within the Aché group, although older men (ages>40) were poorly represented in the study sample. Nevertheless, a mild correlation was observed between Aché TsalA.M. levels and BMI (r=0.133,p=0.0725). Comparison of Aché values with those for other populations confirms the prevalence of significant interpopulational variation in testosterone levels among adult males. Interpopulational variation in male testosterone is not as great, however, as has been documented for ovarian steroids among females, nor is it likely that such variation reflects differences in male fecundity. Nevertheless, such interpopulational variation in salivary testosterone levels may have a functional significance in the regulation of protein anabolism in skeletal muscle, thereby affecting the overall energy budget of the organism. It is suggested that relative suppression of average testosterone may be adaptive under conditions of chronic energy shortage. This research was funded by the National Science Foundation, the Mellon Foundation, Sigma Xi, and Harvard University. The author is a doctoral candidate in biological anthropology at Harvard University. He received his B.A. in anthropology and psychology from UCLA in 1988 and his M.A. in anthropology from Harvard in 1994. His research interests include male reproductive ecology, male hormone function, foraging societies, evolutionary biology, and behavioral evolution.     

Functional-cranial approach to the influence of economic strategy on skull morphology

Environmental factors are assumed to play an important role in the shaping of craniofacial morphology. Here we propose a statistical approach which can be of utility in estimating the magnitude and localization of a particular nongenetic factor upon the specific functional components of the skull. Our analysis is a combination of previous attempts of apportionment of variance and the application of craniofunctional theory. The effect of subsistence strategy on craniofacial functional components was studied on 18 populations of hunter-gatherers and farmers from South America. Results demonstrate that the environmental factors studied likely influenced the masticatory component's size and shape. Even when this effect is not large enough to clearly differentiate among subsistence strategies (since whole craniofacial variation among populations remains greater), the method used here provides interesting clues to localize plastic or adaptive responses to external stimuli.     

Humans as primates: The social relationships of Efe pygmy men in comparative perspective

The Efe are short-statured specialized hunger-gatherers living in the moist tropical forest in northeast Zaire. They live in small mobile groups averaging 18 individuals and practice viripatrilocal residence — what primatologists refer to as male philopatry and female dispersal. This study uses methods commonly employed by primatologists to study the social relationships of Efe men. It compares their association and affiliation patterns with those of two nonhuman primate species that show male philopatry and female transfer. The analyses of 376 hr of focal behavior observations on 16 Efe men reveal that the majority of their associations were with other adult men. Men associated preferentially with kin over non-kin, and with close kin more than with distant kin. Men's close relationships, or companionships,sensu Smuts' (1985) friendships among anubis baboons, were predominantly with other adult men; however, each man who cohabited with a woman had his strongestcompanionship by far with that woman. These quantitative measures of affinity are consistent with the Efe's pattern of viripatrilocal residence, where-by males remain in their natal group with their close male kin and females join or are recruited from other patriclans. The social relationships of Efe men are similar in some respects to those of hamadryas and chimpanzees; however, Efe men's social networks are larger and more fluid. We speculate that the explanation proposed for male philopatry and female dispersal among nonhuman primates also applies to the Efe.     

In the Time of Frost: El Niño and the Political Ecology of Vulnerability in Papua New Guinea

ABSTRACT

Climatic anomalies associated with El Niño bring prolonged droughts and night-time frosts that devastate subsistence gardens in the Papua New Guinea highlands. As a customary process of adaptation to the subsequent food insecurity caused by crop-destroying frosts, people migrate to lower altitude areas where kin and friends provide sustenance and social support. However, with increasing economic development and the demise of collective kin endeavours in the region, long-distance migration networks no longer appear to offer people respite from food insecurity. In this paper, I examine the changes in social responses to El Niño-caused food shortages at varying scales – from subsistence farmers to international aid agencies – over the past several El Niño events. The paper explores the production of vulnerability when customary social-ecological systems of adaptation intersect with regional and national politics, development efforts, and humanitarian aid agencies.     

Estimates of Continental Ancestry Vary Widely among Individuals with the Same mtDNA Haplogroup

The association between a geographical region and an mtDNA haplogroup(s) has provided the basis for using mtDNA haplogroups to infer an individual’s place of origin and genetic ancestry. Although it is well known that ancestry inferences using mtDNA haplogroups and those using genome-wide markers are frequently discrepant, little empirical information exists on the magnitude and scope of such discrepancies between multiple mtDNA haplogroups and worldwide populations. We compared genetic-ancestry inferences made by mtDNA-haplogroup membership to those made by autosomal SNPs in ∼940 samples of the Human Genome Diversity Panel and recently admixed populations from the 1000 Genomes Project. Continental-ancestry proportions often varied widely among individuals sharing the same mtDNA haplogroup. For only half of mtDNA haplogroups did the highest average continental-ancestry proportion match the highest continental-ancestry proportion of a majority of individuals with that haplogroup. Prediction of an individual’s mtDNA haplogroup from his or her continental-ancestry proportions was often incorrect. Collectively, these results indicate that for most individuals in the worldwide populations sampled, mtDNA-haplogroup membership provides limited information about either continental ancestry or continental region of origin.     

African Origin of Human T-Lymphotropic Virus Type 2 (HTLV-2) Supported by a Potential New HTLV-2d Subtype in Congolese Bambuti Efe Pygmies

We identified a potential new subtype within human T-cell lymphotropic virus type 2 (HTLV-2), HTLV-2d, present in members of an isolated Efe Bambuti Pygmy tribe. Two of 23 Efe Pygmies were HTLV-2 seropositive, with HTLV-2 Western blot and enzyme-linked immunosorbent assay reactivities. From one of them the entire genome of the HTLV-2 strain Efe2 could be amplified and sequenced. In all gene regions analyzed, this strain was the most divergent HTLV-2 strain, differing by 2.4% (tax/rex) to 10.7% (long terminal repeat) from both subtypes HTLV-2a and HTLV-2b, yet major functional elements are conserved. The similarity between the HTLV-2 Efe2 Gag and Env proteins and the corresponding HTLV-2a and -2b proteins is consistent with the observed serological reactivity. In the proximal pX region, one of the two alternative splice acceptor sites is abolished in HTLV-2 Efe2. Another interesting feature of this potential new subtype is that it has a Tax protein of 344 amino acids (aa), which is intermediate in length between the HTLV-2a Tax protein (331 aa) and the HTLV-2b and -2c Tax proteins (356 aa) and similar to the simian T-cell lymphotropic virus type 2 (STLV-2) PP1664 Tax protein. Together these two findings suggest a different phenotype for the HTLV-2 Efe2 strain. Phylogenetic analyses confirmed that the Pygmy Efe2 strain potentially belonged to a new and quite divergent subtype, HTLV-2d. When the STLV-2 bonobo viruses PP1664 and PanP were used as an outgroup, it was clear that the Pygmy HTLV-2 Efe2 strain had the longest independent evolution and that HTLV-2 evolution is consistent with an African origin.     

Social assessment of miscanthus cultivation in Croatia: Assessing farmers' preferences and willingness to cultivate the crop

Social aspects of miscanthus cultivation have been investigated in a limited way in the scientific literature. Adopting existing frameworks for social life-cycle assessment enables assessments to include numerous social aspects; however, the relevance of these aspects depends on the local context. This study aims to identify the most relevant social aspects from the farmers' perspective using a previously proposed framework for the assessment of the stakeholder ‘farmer’. It is based on a case study for miscanthus production in Sisak Moslavina in Croatia. The existence of abandoned lands in Croatia presents an opportunity for the cultivation of miscanthus as a potential source of biomass for the production of bio-based materials and fuels. The study seeks to assess the feasibility of cultivating miscanthus in the region, taking into account potential challenges and opportunities, as well as farmers' willingness to adopt the crop, and to understand the reasons behind land abandonment. We conducted a survey among 44 farmers in the region and used a scoring method to identify the most relevant social aspects. The aspects most valued by the farmers were health and safety, access to water, land consolidation and rights, income and local employment, and food security. Responses to the question of whether they would adopt the crop highlight the importance of an established market, good trading conditions and profitability of cultivation. The survey also enabled an understanding of farmers' preferences with respect to the production conditions of crops. The farmers regarded the provision of subsidies as one of the main factors that render a crop attractive. Opportunities for the adoption of the miscanthus cultivation include high yields and low input requirements. Barriers include land conflicts and land availability. Despite the opportunities for miscanthus development in the region, there are important challenges to consider for successful implementation of the crop.     

From social to genetic structures in central Asia

Pastoral and farmer populations, who have coexisted in Central Asia since the fourth millennium B.C., present not only different lifestyles and means of subsistence but also various types of social organization. Pastoral populations are organized into so-called descent groups (tribes, clans, and lineages) and practice exogamous marriages (a man chooses a bride in a different lineage or clan). In Central Asia, these descent groups are patrilineal: The children are systematically affiliated with the descent groups of the father. By contrast, farmer populations are organized into families (extended or nuclear) and often establish endogamous marriages with cousins. This study aims at better understanding the impact of these differences in lifestyle and social organization on the shaping of genetic diversity. We show that pastoral populations exhibit a substantial loss of Y chromosome diversity in comparison to farmers but that no such a difference is observed at the mitochondrial-DNA level. Our analyses indicate that the dynamics of patrilineal descent groups, which implies different male and female sociodemographic histories, is responsible for these sexually-asymmetric genetic patterns. This molecular signature of the pastoral social organization disappears over a few centuries only after conversion to an agricultural way of life.     

Subsistence settlement systems in the prehistory of southwestern Zambia

Humans participate in ecological systems as one means of extracting and distributing environmental resources. Such ecosystems manifest themselves in the archeological record. Settlement systems represent subsistence systems latent with information relevant to explaining the spatial organization of people and change through time. Three subsistence settlement systems were segregated from the record of prehistoric farmers in southwestern Zambia. One is associated with the practice of pioneer populations successively occupying and abandoning favored microenvironments. The second is associated with the cyclical swiddening of a few opportunities within a single microenvironment. The third set spreads centers of production throughout several environmental segments. It is suggested that swiddening the marginal soils of the Zambezi periphery enabled the colonization but did not permit a burgeoning population. It is further suggested that internal networks were crucial to equalization of access to necessary resources and that these were incorporated in the segmentary, descent group.