Bruce Winterhalder

University of California, Davis | UCD · Department of Anthropology & Graduate Group in Ecology

While archaeologists now have demonstrated that barter and trade of material commodities began in prehistory, theoretical efforts to explain these findings are just beginning. We adapt the central place foraging model from behavioral ecology and the missing-market model from development economics to investigate conditions favoring the origins of ho...

Abstract Analyses of racial disparities in police use-of-force against unarmed individuals are central to public policy interventions; however, recent studies have come to apparently paradoxical findings concerning the existence and form of such disparities. Although anti-black racial disparities in U.S. police shootings have been consistently docu...

A theoretical and applied literature has suggested that foragers search using Lévy flights, since Lévy flights can maximize the efficiency of search in the absence of information on the location of randomly distributed prey. Foragers, however, often have available to them at least some information about the distribution of prey, gained either throu...

Active search for prey is energetically costly, so understanding how foragers optimize search has been central to foraging theory. Some theoretical work has suggested that foragers of randomly distributed prey should search using Lévy flights, while work on area-restricted and intermittent search strategies has demonstrated that foragers can use th...

We adopt an imagined exchequer, the functionary responsible in an early polity for securing resources from its agrarian subjects, and we develop a feature-rich demographic and environmental model to explore the population ecology of agricultural production in the context of population growth, Malthusian constraints and economic exploitation. The mo...

Humans have two features rare in mammals: our locomotor muscles are dominated by fatigue-resistant fibres and we effectively dissipate through sweating the metabolic heat generated through prolonged, elevated activity. A promising evolutionary explanation of these features is the endurance pursuit (EP) hypothesis, which argues that both traits evol...

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities—incorporating market integration—are associated with fertility in 10,250 women from 27 small-scale societies and found con...

To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while neverth...

Explaining variation in hunter-gatherer livelihoods hinges on our ability to predict the tradeoffs and opportunities of pursuing different kinds of prey. Central to this problem is the commonly held assumption that larger animals provide higher returns upon encounter than smaller ones. However, to test this assumption, actualistic observations of h...

We report functional relationships between humans and canines based on observations in the village of Santa Cruz (Toledo District, Belize), emphasizing the cultural ecology of dogs in this lowland tropical rainforest setting and milpa agriculture subsistence system. Dogs pursue animals threatening field crops; they deter forest herbivores by leavin...

Cesario et al. argue that benchmarking the relative counts of killings by police on relative crime rates, rather than relative population sizes, generates a measure of racial disparity in the use of lethal force that is unbiased by differential crime rates. Their publication, however, lacked any formal derivation showing that their benchmarking met...

Human adaptation depends on the integration of slow life history, complex production skills, and extensive sociality. Refining and testing models of the evolution of human life history and cultural learning benefit from increasingly accurate measurement of knowledge, skills, and rates of production with age. We pursue this goal by inferring hunters...

Aim As a response of pastoralists to climate change, nomadic migration deeply shaped Chinese history during the imperial era. Existing research on climate‐driven nomadic migration is conducted mainly on a national–continental scale. To advance the current work, we aim to resolve migratory movements at a provincial–regional scale using a large and l...

We develop a method of analysis for testing the marginal value theorem (MVT) in natural settings that does not require an independent definition or mapping of patches. We draw on recent theoretical work on area-restricted search (ARS) that links turning-angle and step-size changes to geographically localized encounter-rates. These models allow us t...

Human adaptation depends upon the integration of slow life history, complex production skills, and extensive sociality. Refining and testing models of the evolution of human life history and cultural learning will benefit from increasingly accurate measurement of knowledge, skills, and rates of production with age. We pursue this goal by inferring...

Additional methodological details and results of robustness checks. (PDF)

The sub-section 2.1 of the Supplementary Information file in the original article was incorrect. This whole sub-section has now been removed.

Monogamy appears to have become the predominant human mating system with the emergence of highly unequal agricultural populations that replaced relatively egalitarian horticultural populations, challenging the conventional idea-based on the polygyny threshold model-that polygyny should be positively associated with wealth inequality. To address thi...

Changes in social organization accelerated on California's northern Channel Islands beginning around 1300 cal BP. These changes were associated with shifts in settlement and subsistence patterns related in part to drought conditions during the Medieval Climatic Anomaly (MCA; 1150-600 cal BP). By the end of the MCA, settlement patterns demonstrate e...

This study provides an ecological explanation for the distribution of Arctic Small Tool tradition (ASTt) settlements in Alaska and the origin of their arctic maritime adaptation. Theoretically grounded in the ideal free distribution (IFD) model, which predicts that higher ranked habitats will be occupied first and most continuously, we contend that...

Using targeted survey, excavation, and radiocarbon dating, we assess the extent to which human settlement patterns on California's northern Channel Islands fit predictions arising from the ideal free distribution (IFD): (1) people first established and expanded permanent settlements in the regions ranked high for environmental resource suitability;...

Evolutionary ecological models of human fertility predict that (1) parents will bias investment toward the sex with the highest fitness prospects in a particular socio-ecological context; (2) fertility is subject to quantity-quality trade-offs; and (3) fertility decisions will be sensitive to both predictable and stochastic mortality risk and the r...

We present a quantitative account based on ethnographic and documentary research of the prevalence of female genital modification (FGMo) in the African diaspora and indigenous populations of Colombia. We use these data to test hypotheses concerning the cultural evolutionary drivers of costly trait persistence, attenuation, and intergroup transmissi...

Using complementary behavioural and population ecological models, we explore the role of production risk, normal surplus and inter-annual food storage in the adaptations of societies dependent on seasonal agriculture. We find that (a) household-level, risk-sensitive adaption to unpredictable environmental variation in annual agricultural yields is...

Drawing on Skellam's (1958) work on sampling animal populations using transects, we derive a behavioral ecological model of the choice between sit-and-wait and active-search hunting. Using simple, biologically-based assumptions about the characteristics of predator and prey, we show how an empirically definable parameter space favoring active-searc...

Using a sample of 40 sources reporting milpa and mucuna-intercropped maize yields in Mesoamerica, we test Boserup's (1965) prediction that fallow is reduced as a result of growing population density. We further examine direct and indirect effects of population density on yield. We find only mixed support for Boserupian intensification. Fallow perio...

Objectives: We conduct a revaluation of the Thornhill and Fincher research project on parasites using finely-resolved geographic data on parasite prevalence, individual-level sociocultural data, and multilevel Bayesian modeling. In contrast to the evolutionary psychological mechanisms linking parasites to human behavior and cultural characteristic...

We investigated the mechanism of epidemics with the impacts of climate change and socio-economic fluctuations in the Ming and Qing Dynasties in China (AD 1368-1901). Using long-term and high-quality datasets, this study is the first quantitative research that verifies the 'climate change → economy → epidemics' mechanism in historical China by stati...

The World Until Yesterday is the third in a series of best-selling and prize-winning volumes by Jared Diamond addressing the large issues of our current condition and possible futures. In Guns, Germs and Steel (1997) Diamond offers an account of how we have come to the present global situation of wide disparities in socio-economic development and w...

Analyses of terminal long count dates from stone monuments in the Maya lowlands have played a central role in characterizing the rise and "collapse" of polities during the Late and Terminal Classic periods (A.D. 730-910). Previous studies propose a directional abandonment of large political centers from west-to-east. We retest the west-to-east hypo...

Since despotism is a common evolutionary development in human history, we seek to understand the conditions under which it can originate, persist, and affect population trajectories. We describe a general system of population ecology equations representing the Ideal Free and Despotic Distributions for one and two habitats, one of which contains a d...

Analysis of a natural fertility agrarian society with a multi-variate model of population ecology isolates three distinct phases of population growth following settlement of a new habitat: (1) a sometimes lengthy copial phase of surplus food production and constant vital rates; (2) a brief transition phase in which food shortages rapidly cause incr...

When adult males are temporarily away from the household, observational evidence suggests cross-cultural and intra-cultural variation in the effects of their absence on the labor of other household members. In subsistence-based economies, we predict that other adolescent or older members will work more in essential production activities that otherw...

The role of climate change in the development and demise of Classic Maya civilization (300 to 1000 C.E.) remains controversial because of the absence of well-dated climate and archaeological sequences. We present a precisely dated subannual climate record for the past 2000 years from Yok Balum Cave, Belize. From comparison of this record with histo...

The prehistoric establishment and expansion of permanent settlements on the Northern Channel Islands of southern California generally follows a pattern predicted by the population ecology model, the ideal free distribution (IFD). We determine this by comparing the abundant archaeological record of these Islands against a careful quantification of h...

Aim To highlight the importance of combining the geographies of sociocultural adaptation and biodiversity risk for creating global change conservation strategies. Location Global. Methods We review global conservation adaptation strategies and the geographies that influence biological risk, as well as sociocultural capacity to set priorities for a...

p>Key trends in California prehistory diverge from those characteristic of other world regions; sophisticated advances in the application of human behavioral ecology to archaeological interpretation help us to understand why. Significant interpretive advances have been stimulated by the on-going "provisioning" versus "costly signaling" debate. We a...

Explanations of the socioeconomic changes accompanying the transition from foraging through mixed economies to societies that take up full-time agriculture will entail concepts of risk, discounting, economies of scale, and transaction costs. The spatial form and temporal scale of agricultural production fundamentally change the parameters of risk m...

This article provides a brief survey of the analysis of outcome risk: what it is, in what circumstance it is important, what the analytical tools are for describing and analysing it, what examples demonstrate the utility of these tools, and what inferences can be drawn from a risk-sensitive approach to behaviour. It also summarises empirical eviden...

Ugan, Bright and Rogers [When is technology worth the trouble? Journal of Archaeological Science 30 (10) (2003) 1315–1329] develop procurement and processing versions of an optimization model, termed the tech investment model, to formalize the conditions that favor investing time in the manufacture of more productive but more costly technologies. T...

Human behavioral ecology applies theory and method developed in evolutionary biology, anthropology and economics to elucidate adaptive variation in human behavior, particularly social behavior. Hypotheses about resource use, mating and parenting strategies, cooperation and competition, and life history are derived from models using a selectionist l...

Islands in Oceania were some of the last habitable land masses on earth to be colonized by humans. Current archaeological evidence suggests that these islands were colonized episodically rather than continuously, and that bursts of migration were followed by longer periods of sedentism and population growth. The decision to colonize isolated, unocc...

This innovative volume is the first collective effort by archaeologists and ethnographers to use concepts and models from human behavioral ecology to explore one of the most consequential transitions in human history: the origins of agriculture. Carefully balancing theory and detailed empirical study, and drawing from a series of ethnographic and a...

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Child survival is probabilistic, but the unpredictability in family formation and completed family size has been neglected in the fertility literature. In many societies, ending the family cycle with too few or too many surviving offspring entails serious social, economic, or fitness consequences. A model of risk- (or variance-) sensitive adaptive...

Two conditions are sufficient to indicate the need for risk-sensitive, adaptive analysis: (i) the outcomes of a behavior must be unpredictable to some degree and (ii) the relationship between outcomes and their value (in terms of fitness or utility) must be nonlinear. We argue that these conditions are common, and develop a general model for the an...

This paper has three goals: (1) to define the anthropological subfield of human behavioral ecology (HBE) and characterize recent progress in this research tradition; (2) to address Joseph's (2000) critique of HBE from the perspective of an advocate of that field; and (3) to suggest features that make for effective criticism of research traditions....

When, why, and how early humans began to eat meat are three of the most fundamental unresolved questions in the study of human origins. Before 2.5 million years ago the presence and importance of meat in the hominid diet is unkown. After stone tools appear in the fossil record it seems clear that meat was eaten in increasing quantities, but whether...

Hunter-gatherers: An Interdisciplinary Perspective

We present a model that calculates incident solar radiation falling on terraced and unterraced fields in steep slope environments. The results are presented as a function of altitude, latitude, slope aspect, slope angle, and season. The net solar benefit or cost from slope leveling (terracing) diÄers significantly according to these situational fac...

cesses of resource competition and transfers, now supplement and enrich those of resource production. Demo- graphic and life history analyses have begun to show how ecological factors of production and distribution relate to those of mortality, fertility, and life

Risk-sensitive analysis of subsistence adaptations is warranted when (i) outcomes are to some degree unpredictable and (ii) they have nonlinear consequences for fitness and/or utility. Both conditions are likely to be common among peoples studied by ecologicll anthropologists and archaeologists. We develop a general conceptual model of risk. We the...

Population ecology and foraging theory can be combined to simulate the population dynamics of hunter‐gatherers and their prey resources. Such simulation study is important to issues of conservation because many of the population processes that link human foragers and their prey occur over time scales that elude both ethnographic and archaeological...

Behavioral ecologists combine evolutionary models of mechanism and ecological models of circumstance to analyze the origins and forms of intragroup exchange among social foragers, a category that includes primates, hominids, and recent and modern hunter-gatherers. Evolutionary mechanisms encompass individual, sexual, reciprocal, kin, group, and cul...

Using marginal analysis to represent Blurton Jones's concept of tolerated theft, I show how equilibrium resource transfers among individuals might be affected by foraging behavior, resource qualities, and number of participants. The model applies to hominids and other species that exchange or share food or other resources. Among the results: Tolera...

Two chimpanzees stalk, isolate, and kill a red colobus monkey. An attendant primatologist notes that parts of the prey are relinquished selectively to onlooking scroungers (Fig. 1). A human forager returns to camp mid-afternoon with a freshly killed, medium-sized ungulate. Later in the day, an ethnographer observes that shared portions of the anima...

Two chimpanzees stalk, isolate, and kill a red colobus monkey. An attendant primatologist notes that parts of the prey are relinquished selectively to onlooking scroungers (Fig. 1). A human forager returns to camp mid-afternoon with a freshly killed, medium-sized ungulate. Later in the day, an ethnographer observes that shared portions of the anima...

Irrigation at High Altitudes: The Social Organization of Water Control Systems in the Andes

Anthropological views on the labour effort required of hunter-gatherers have flip-flopped between stereotypic positions depicting either very limited subsistence work or long exertion. This is partly because the discipline has lacked an encompassing framework for the analysis of work, resources and population in foraging societies. A computer simul...

Evolutionary Ecology and Human Behavior

Computerized analysis of a geographic database (GIS) for Cuyo Cuyo, (Dept. Puno, Peru) is used to correlate the agricultural production zones of two adjacent communities to altitude, slope, aspect, and other geomorphological features of the high-altitude eastern escarpment landscape. The techniques exemplified will allow ecological anthropologists...

In this paper we combine foraging theory and population biology models to simulate dynamic relationships between hunter-gatherers and their prey resources. Hunter-gatherer population growth responds to the net marginal rate of foraging; prey population growth responds logistically to exploitation. Thus conceived, the relationship between forager an...

MY TITLE ALLUDES TO HUNTING. THE IMAGERY IS DELIBERATE: I intend a somewhat predatory engagement with the subject. How do ecological factors affect hunter-gatherer decisions about the harvest of non-produced food resources? What are the ecological strategies of the food quest? And, especially,. how does one go about asking these questions? What is...

Foraging models can predict the optimal diet selection for an organism which has the goal of maximizing its net acquisition rate for energy while hunting and gathering. Here a simulation methodology is used to determine the optimal diet selection under the assumption that the forager's goal is to minimize the risk of an energy shortfall. The result...

A simple graphical technique relates 2 existing foraging models to marginal valuations of the time and energy currencies used as proxies for fitness. Predictions are responsive to important theoretical assumptions of evolutionary ecology research: costs in behavioral trade-offs are opportunity costs, often evaluated at the margin. The approach offe...

Our objectives in this final chapter are to consolidate our observations on one major piece of unfinished business—cold adaptation—and to describe the pattern of general adaptation which we have observed in our studies in boreal anthropology.

In 1974–1976, in the book Zoönomia or the Laws of Organic Life, Erasmus Darwin (1794) speculated that modification of species was brought about through the satisfaction of three wants. He identified them with admirable directness as “lust, hunger, and danger.” In the more prosaic but parallel terminology of contemporary evolutionary ecology these h...

This chapter analyzes the climate, landscape, flora, and fauna of the boreal forest in northern Ontario. It emphasizes facets of this ecosystem known to be of importance to humans. Its goal is to establish the context—the mix of physical and biotic factors, some patterned and some irregular in occurrence—in which human adaptation occurs. The boreal...

Fossil evidence from the Plio-Pleistocene of Africa apparently has confirmed a multi-lineage interpretation of early hominid evolution. Empirical refutation of the single species hypothesis must now be matched to the evolutionary ecology theory, which can underwrite taxonomic assessment and help to explain sympatric hominid coexistence. This paper...