About

I am a broadly trained evolutionary anthropologist and my research focuses on the behavioral ecology of hunter-gatherers. I am interested in learning how basic challenges of survival and reproduction that arise from life as a hunter-gatherer have shaped human biology, behavior, and culture. I have been carrying out research with the Hadza community of northern Tanzania since 2004. My research is interdisciplinary and involves a mix of quantitative and qualitative methods. Foraging and food sharing, mobility, and social organization are core themes of my research. I also study the demography and life history of our closest primate relatives, wild chimpanzees.

Research topics

• Endocrinology
• Biology
• Mathematics
• Ecology
• Psychology
• Medicine
• Developmental psychology
• Statistics
• Demography
• Management
• Materials science
• Geography
• Chromatography
• Physical medicine and rehabilitation
• Applied mathematics
• Gerontology
• Archaeology
• Evolutionary biology
• Biochemistry
• Chemistry
• Animal science
• Zoology
• Social psychology
• Communication

Selected publications

• Female fertility and infant survivorship increase following lethal intergroup aggression and territorial expansion in wild chimpanzees

  Proceedings of the National Academy of Sciences · 2025-11-17 · 3 citations

  articleOpen access1st authorCorresponding

  Lethal coalitionary intergroup aggression is a conspicuous aspect of wild chimpanzee behavior. Evidence indicates that such violence can lead to territorial expansion, but whether this results in fitness benefits is unknown. Here, we show that female fertility and infant survivorship increased after males in the Ngogo chimpanzee community killed members of neighboring groups and expanded their territory. These findings demonstrate the fitness benefits of intergroup killing in one of our two closest living relatives and contribute to the debate regarding its adaptive significance.

  PublisherOA PDFDOI

• Energy expenditure and obesity across the economic spectrum

  Proceedings of the National Academy of Sciences · 2025-07-14 · 23 citations

  articleOpen access

  Global economic development has been associated with an increased prevalence of obesity and related health problems. Increased caloric intake and reduced energy expenditure are both cited as development-related contributors to the obesity crisis, but their relative importance remains unresolved. Here, we examine energy expenditure and two measures of obesity (body fat percentage and body mass index, BMI) for 4,213 adults from 34 populations across six continents and a wide range of lifestyles and economies, including hunter-gatherer, pastoralist, farming, and industrialized populations. Economic development was positively associated with greater body mass, BMI, and body fat, but also with greater total, basal, and activity energy expenditure. Body size-adjusted total and basal energy expenditures both decreased approximately 6 to 11% with increasing economic development, but were highly variable among populations and did not correspond closely with lifestyle. Body size-adjusted total energy expenditure was negatively, but weakly, associated with measures of obesity, accounting for roughly one-tenth of the elevated body fat percentage and BMI associated with economic development. In contrast, estimated energy intake was greater in economically developed populations, and in populations with available data (n = 25), the percentage of ultraprocessed food in the diet was associated with body fat percentage, suggesting that dietary intake plays a far greater role than reduced energy expenditure in obesity related to economic development.

  PublisherOA PDFDOI

• Reproductive inequality in humans and other mammals

  London School of Economics and Political Science Research Online (London School of Economics and Political Science) · 2025-03-19

  articleOpen access

  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 nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited degree of polygyny in the human societies that practice it, and to the importance of unequally held rival resources to women's fitness. The muted reproductive inequality observed in humans appears to be linked to several unusual characteristics of our species-including high levels of cooperation among males, high dependence on unequally held rival resources, complementarities between maternal and paternal investment, as well as social and legal institutions that enforce monogamous norms.

  PublisherOA PDFDOI

• Sex Differences in Measures of Energy Expenditure and Body Composition in Young, Middle-Aged, and Older Adults

  Current Developments in Nutrition · 2025-12-10

  articleOpen access

  Background: Total daily energy expenditure (TDEE) is vital for energy balance and cardiometabolic health, yet its trajectory across the lifespan, particularly in females, remains poorly understood. Objectives: We sought to examine the effects of aging and sex on body composition and TDEE. Methods: In a cross-sectional analysis of data from research centers across 9 European Countries and the United States from the International Atomic Energy Agency database, TDEE and body composition measures of 2326 participants (1560W/766M; 50.7 ± 12 .6 y) were stratified across age groups: young (30-39 y; YOUNG), middle-aged (40-54 y; MID), and old (55-70 y; OLD). Doubly labeled water was used to estimate TDEE and fat-free mass (FFM). Fat mass (FM) was calculated as the difference between body mass and FFM, and %fat was ratio between FM and body mass as a percentage. Linear models were used for analysis. Results: 0.001). Adjusted TDEE was similar within age groups between females and males. Conclusions: These results suggest that age influences changes in body composition and energy expenditure similarly between males and females. The most significant change in TDEE occurs as individuals transition from middle age to older adulthood. Females generally have a higher percentage of %fat and FM, along with lower FFM, compared with males across all age groups. These findings are important for understanding how aging affects metabolism and body composition, which could inform sex-specific health strategies and interventions.

  PublisherDOI

• Hadza Landscape Burning

  Human Nature · 2024-08-20 · 4 citations

  articleSenior author
  PublisherDOI

• Beyond the here and now: hunter–gatherer socio-spatial complexity and the evolution of language

  Philosophical Transactions of the Royal Society B Biological Sciences · 2024-09-04 · 3 citations

  reviewOpen access1st authorCorresponding

  Human evolutionary ecology stands to benefit by integrating theory and methods developed in movement ecology, and in turn, to make contributions to the broader field of movement ecology by leveraging our species’ distinct attributes. In this paper, we review data and evolutionary models suggesting that major changes in socio-spatial behaviour accompanied the evolution of language. To illustrate and explore these issues, we present a comparison of GPS measures of the socio-spatial behaviour of Hadza hunter–gatherers of northern Tanzania to those of olive baboons ( Papio anubis ), a comparatively small-brained primate that is also savanna-adapted. While standard spatial metrics show modest differences, measures of spatial diversity, landscape exploration and spatiotemporal displacement between individuals differ markedly. Groups of Hadza foragers rapidly accumulate a vast, diverse knowledge pool about places and things over the horizon, contrasting with the baboon’s narrower and more homogeneous pool of ecological information. The larger and more complex socio-spatial world illustrated by the Hadza is one where heightened cognitive abilities for spatial and episodic memory, navigation, perspective taking and communication about things beyond the here and now all have clear value. This article is part of the theme issue ‘The spatial–social interface: a theoretical and empirical integration’.

  PublisherOA PDFDOI

• Lifestyle and patterns of physical activity in <scp>Hadza</scp> foragers

  American Journal of Biological Anthropology · 2023-09-20 · 7 citations

  articleOpen access

  OBJECTIVES: Physically active lifestyles are associated with several health benefits. Physical activity (PA) levels are low in post-industrial populations, but generally high throughout life in subsistence populations. The Hadza are a subsistence-oriented foraging population in Tanzania known for being physically active, but it is unknown how recent increases in market integration may have altered their PA patterns. In this study, we examine PA patterns for Hadza women and men who engage in different amounts of traditional foraging. MATERIALS AND METHODS: One hundred and seventy seven Hadza participants (51% female, 19-87 years) wore an Axivity accelerometer (dominant wrist) for ~6 days during dry season months. We evaluated the effects of age, sex, and lifestyle measures on four PA measures that capture different aspects of the PA profile. RESULTS: Participants engaged in high levels of both moderate-intensity PA and inactivity. Although PA levels were negatively associated with age, older participants were still highly active. We found no differences in PA between participants living in more traditional "bush" camps and those living in more settled "village" camps. Mobility was positively associated with step counts for female participants, and schooling was positively associated with inactive time for male participants. CONCLUSIONS: The similarity in PA patterns between Hadza participants in different camp types suggests that high PA levels characterize subsistence lifestyles generally. The sex-based difference in the effects of mobility and schooling on PA could be a reflection of the Hadza's gender-based division of labor, or indicate that changes to subsistence-oriented lifestyles impact women and men in different ways.

  PublisherOA PDFDOI

• Do honey badgers and greater honeyguide birds cooperate to access bees' nests? Ecological evidence and honey‐hunter accounts

  Journal of Zoology · 2023-06-29 · 5 citations

  articleOpen access

  Abstract In parts of Africa, greater honeyguides ( Indicator indicator ) lead people to bees' nests, after which people harvest the honey, and make beeswax and larvae accessible to the honeyguide. In scientific and popular literature, a similar cooperative relationship is frequently described between honeyguides and honey badgers ( Mellivora capensis ), yet the evidence that this occurs is unclear. Such a partnership may have implications for the origins of our own species' cooperation with honeyguides and for the ecology and conservation of both honey badgers and honeyguides. Here, we review the evidence that honey badgers and honeyguides cooperate to access bees' nests, drawing from the published literature, from our own observations whilst studying both species, and by conducting 394 interviews with honey‐hunters in 11 communities across nine African countries. We find that the scientific evidence relies on incomplete and second‐hand accounts and does not convincingly indicate that the two species cooperate. The majority of honey‐hunters we interviewed were similarly doubtful about the interaction, but many interviewees in the Hadzabe, Maasai, and mixed culture communities in Tanzania reported having seen honey badgers and honeyguides interact, and think that they do cooperate. This complementary approach suggests that the most likely scenario is that the interaction does occur but is highly localized or extremely difficult to observe, or both. With substantial uncertainty remaining, we outline empirical studies that would clarify whether and where honeyguides and honey badgers cooperate, and emphasize the value of integrating scientific and cultural knowledge in ecology.

  PublisherOA PDFDOI

• Demographic and hormonal evidence for menopause in wild chimpanzees

  Science · 2023 · 57 citations

  1st authorCorresponding
  • Biology
  • Demography
  • Ecology

  Among mammals, post-reproductive life spans are currently documented only in humans and a few species of toothed whales. Here we show that a post-reproductive life span exists among wild chimpanzees in the Ngogo community of Kibale National Park, Uganda. Post-reproductive representation was 0.195, indicating that a female who reached adulthood could expect to live about one-fifth of her adult life in a post-reproductive state, around half as long as human hunter-gatherers. Post-reproductive females exhibited hormonal signatures of menopause, including sharply increasing gonadotropins after age 50. We discuss whether post-reproductive life spans in wild chimpanzees occur only rarely, as a short-term response to favorable ecological conditions, or instead are an evolved species-typical trait as well as the implications of these alternatives for our understanding of the evolution of post-reproductive life spans.

  PublisherOA PDFDOI

• Culturally determined interspecies communication between humans and honeyguides

  Science · 2023-12-07 · 23 citations

  articleOpen accessSenior authorCorresponding

  Species interactions that vary across environments can create geographical mosaics of genetic coevolution. However, traits mediating species interactions are sometimes culturally inherited. Here we show that traditions of interspecies communication between people and wild birds vary in a culturally determined geographical mosaic. Honey hunters in different parts of Africa use different calls to communicate with greater honeyguides ( Indicator indicator ) that lead them to bees’ nests. We show experimentally that honeyguides in Tanzania and Mozambique discriminate among honey hunters’ calls, responding more readily to local than to foreign calls. This was not explained by variation in sound transmission and instead suggests that honeyguides learn local human signals. We discuss the forces stabilizing and diversifying interspecies communication traditions, and the potential for cultural coevolution between species.

  PublisherOA PDFDOI

Recent grants

• RAPID: Time Critical Preservation of Hunter-Gatherer Ethnographic Data

  NSF · $75k · 2015–2017

• Evaluating competing models of human technological adaptation

  NSF · $148k · 2022–2023

• Collaborative Research: The Evolutionary Biology and Health Consequences of Human Inactivity

  NSF · $20k · 2014–2017

Frequent coauthors

• Herman Pontzer

  Duke Institute for Health Innovation

  95 shared

• John R. Speakman

  Chinese Academy of Sciences

  72 shared

• Sonja Entringer

  Humboldt-Universität zu Berlin

  59 shared

• David A. Raichlen

  University of Southern California

  57 shared

• Stéphane Blanc

  Centre de Coopération Internationale en Recherche Agronomique pour le Développement

  55 shared

• Xueying Zhang

  44 shared

• Yosuke Yamada

  44 shared

• Robert Ojiambo

  University of Global Health Equity

  37 shared

Labs

• Brian Wood's LabPI

  Evolutionary approaches to human behavior, psychology, culture, development, and genetics, with a focus on the comparative study of non-human primates.

Education

• B.A., Anthropology

  University of California, Davis

  1999

• M.S., Computer Science

  Cal Poly San Luis Obispo

  2004

• Ph.D., Anthropology

  Harvard University

  2010

• Other, Ecological Anthropology

  Stanford University

  2012