The subsistence technology of capuchins

Via Oswalt’s system of classification, I compare the tool-kits of wild and captive capuchins with those of Tanzanian chimpanzees and Tasmanian aborigines. The results indicate that capuchins have tool-kits that are smaller, and have lower ratios of artifacts to naturefacts, than those of Tanzanian chimpanzees and Tasmanian aborigines. Accordingly, Oswalt’s system can be used productively to assess the relative technological skills of monkeys versus those of apes and humans.     

The subsistence technology of capuchins

Via Oswalt’s system of classification, I compare the tool-kits of wild and captive capuchins with those of Tanzanian chimpanzees and Tasmanian aborigines. The results indicate that capuchins have tool-kits that are smaller, and have lower ratios of artifacts to naturefacts, than those of Tanzanian chimpanzees and Tasmanian aborigines. Accordingly, Oswalt’s system can be used productively to assess the relative technological skills of monkeys versus those of apes and humans.     

A dynamic nonlinear optimization study of Mountain Pima subsistence technology

A dynamic nonlinear optimization analysis of subsistence patterns of the Mountain Pima of Chihuahua, Mexico, included requirements for adequate amounts of calories, calcium, vitamin A, vitamin C, and balanced protein. Two methods of incorporating nonenergy nutritional needs into a time minimization program were compared. The first was a constraint model with sharp boundaries between adequacy and fatality. The second involved multiplying the total work time by a series of nutrient indexing factors. Each factor was calculated as a function of the ratio between the recommended and actual rates of intake for all months and nutrients considered. Oxalate composition of some resources and seasonal variation in resource availability were taken into account. Two sets of data were analyzed, one for a year of adequate rainfall, the other for a year of severe drought. The predictions of the indexing model agreed more closely with observed intake patterns than did the predictions of the constraint model.     

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.     

Chimpanzee violence: femmes fatales

New observations of coalitionary infanticide by female chimpanzees in Uganda shed light on the nature of female competition.     

Chimpanzee tool technology in the Goualougo Triangle, Republic of Congo

With the exception of humans, chimpanzees show the most diverse and complex tool-using repertoires of all extant species. Specific tool repertoires differ between wild chimpanzee populations, but no apparent genetic or environmental factors have emerged as definitive forces shaping variation between populations. However, identification of such patterns has likely been hindered by a lack of information from chimpanzee taxa residing in central Africa. We report our observations of the technological system of chimpanzees in the Goualougo Triangle, located in the Republic of Congo, which is the first study to compile a complete tool repertoire from the Lower Guinean subspecies of chimpanzee (Pan troglodytes troglodytes). Between 1999 and 2006, we documented the tool use of chimpanzees by direct observations, remote video monitoring, and collections of tool assemblages. We observed 22 different types of tool behavior, almost half of which were habitual (shown repeatedly by several individuals) or customary (shown by most members of at least one age-sex class). Several behaviors considered universals among chimpanzees were confirmed in this population, but we also report the first observations of known individuals using tools to perforate termite nests, puncture termite nests, pound for honey, and use leafy twigs for rain cover. Tool behavior in this chimpanzee population ranged from simple tasks to hierarchical sequences. We report three different tool sets and a high degree of tool-material selectivity for particular tasks, which are otherwise rare in wild chimpanzees. Chimpanzees in the Goualougo Triangle are shown to have one of the largest and most complex tool repertoires reported in wild chimpanzee populations. We highlight new insights from this chimpanzee population to our understanding of ape technological systems and evolutionary models of tool-using behavior.     

Archaeology, anthropology and subsistence

Wherever and whenever one may wish to place the roots of the disciplines of archaeology and anthropology, the subsistence-based categories of savage hunters and civilized farmers still lie at the heart of the division of much contemporary intellectual labour. The sources of these categories can be traced back into the seventeenth century, although they were first systematically related to (pre)history and cultural difference in the mid-eighteenth century. The subsequent relations between these categories and the changing disciplines of ethnology, ethnography, and archaeology have not remained constant over time or space. However, the underlying assumption that subsistence practices are meaningful and useful societal categories has persisted for the past 250 years. The relationship between such concepts, the closely associated idea of social evolution, and anthropology and archaeology, in particular from the mid-nineteenth century to the present, is examined. It is suggested that finding ways of writing across such categories is a necessary step for the future of both disciplines.     

Chimpanzee 'folk physics': bringing failures into focus

Differences between individuals are the raw material from which theories of the evolution and ontogeny of cognition are built. For example, when 4-year-old children pass a test requiring them to communicate the content of another's falsely held belief, while 3-year-olds fail, we know that something must change over the course of the third year of life. In the search for what develops or evolves, the typical route is to probe the extents and limits of successful individuals' ability. Another is to focus on those that failed, and find out what difference or lack prevented them from passing the task. Recent research in developmental psychology has harnessed individual differences to illuminate the cognitive mechanisms that emerge to enable success. We apply this approach to explaining some of the failures made by chimpanzees when using tools to solve problems. Twelve of 16 chimpanzees failed to discriminate between a complete and a broken tool when, after being set down, the ends of the broken one were aligned in front of them. There was a correlation between performance on this aligned task and another in which after being set down, the centre of both tools was covered, suggesting that the limiting factor was not the representation of connection, but memory or attention. Some chimpanzees that passed the aligned task passed a task in which the location of the broken tool was never visible but had to be inferred.     

Chimpanzee behavior: there's no place like home

During times of crisis, humans often seek the comforts of home. New observations indicate that, during periods of food shortage, male chimpanzees behave in similar fashion by returning to the areas they occupied with their mothers in youth.     

The Cultured Chimpanzee: Reflections on Cultural Primatology

The Cultured Chimpanzee: Reflections on Cultural Primatology . William C. McGrew. Cambridge: Cambridge University Press, 2004. 248 pp.