About

Richard W. Wrangham (PhD, Cambridge University, 1975) is Ruth B. Moore Professor of Biological Anthropology at Harvard University. He founded the Kibale Chimpanzee Project in 1987 and has conducted extensive research on primate ecology, nutrition, and social behavior. Wrangham is best known for his work on the evolution of human warfare and human aggression, which he has described in the books Demonic Males and The Goodness Paradox. He has also written extensively on the role of cooking in human evolution, as detailed in his book Catching Fire: How Cooking Made Us Human. His research focuses on understanding the behavioral and ecological aspects of chimpanzees, contributing significantly to the fields of primatology and human evolutionary studies.

Research topics

• Biology
• Ecology
• Zoology
• Genetics
• Evolutionary biology
• Demography
• Sociology
• Developmental psychology
• Psychology
• Immunology
• Social psychology
• Communication
• Mathematics
• Neuroscience

Selected publications

• Exposure and hormone associations of pesticides and flame retardants among primates in Uganda

  Environmental Toxicology and Chemistry · 2025-05-19 · 1 citations

  articleOpen access

  Primates exhibit diverse diets and related dietary adaptations which are expected to play a role in the exposure and toxicity of persistent organic pollutants. In the habitat of four primate species in Kibale National Park, Uganda, we quantified brominated flame retardants and organochlorine pesticides (OCPs) in air samples (n = 9), dietary plant samples (n = 32), and fecal samples from adult males and juveniles (n = 53). We also measured the fecal hormone metabolites cortisol and estradiol in juveniles (n = 38). In dietary plant samples, Σ32 brominated flame retardants (BFRs) ranged from 12-22 ng/g and Σ21OCPs ranged from 61-334 ng/g across primate species. In primate fecal samples, median Σ32BFRs ranged from 6-158 ng/g and Σ21OCPs s ranged from 39-261 ng/g. In juveniles, higher Σ32BFRs were associated with decreased cortisol in baboons and chimpanzees as well as total polybrominated diphenyl ethers and dechlorane plus in baboons and chimpanzees, respectively. In red-tailed monkeys, 2-ethylhexyl-2,3,4,5-tetrabromobenzoate and Σ21OCPs were positively associated with cortisol. No significant associations between targeted pollutants and hormones were found in red colobus nor between estradiol and any chemical for any species. Our results indicate that despite their phylogenetic relatedness, the exposure, movement, and potential endocrine activity of pollutants varies across primate species. We suggest future studies exploring the mechanisms underlying phytochemical detoxification may help further elucidate connections between dietary niche and pollutant sensitivity in primates and at a broad taxonomic scale.

  PublisherOA PDFDOI

• Jane Goodall obituary: pioneer primatologist who inspired generations of scientists

  Nature · 2025-10-06

  article1st authorCorresponding
  PublisherDOI

• Chimpanzee mothers, but not fathers, influence offspring vocal–visual communicative behavior

  PLoS Biology · 2025-08-05

  articleOpen accessCorresponding

  Face-to-face communication in humans typically consists of a combination of vocal utterances and body language. Similarly, our closest living relatives, chimpanzees, produce multiple vocal signals alongside a wide array of manual gestures, body postures and facial expressions. In humans, the ontogenetic development of communicative behavior is known to be heavily influenced by the child's primary caretakers. In chimpanzees, the extent to which communicative behavior is learned, as opposed to genetically inherited, remains openly debated. Here, we address this issue within the context of multi-modal communication by investigating kinship patterns in the production of visual behaviors alongside vocal signals in wild chimpanzees from the Kanyawara community, Uganda. We report a similarity in the number of visual behaviors combined with vocal signals between individuals who are related via their mother, while no similarity is observed between paternal relatives, in line with the observation that chimpanzee mothers constitute the primary caretakers, while fathers are not involved in parenting. We conclude that the development of this aspect of multi-modal communicative behavior is unlikely to be genetically driven and is rather a result of learning via exposure to social templates, akin to processes involved in the acquisition of human communication.

  PublisherDOI

• Sex differences in health burdens across the lifespan in wild chimpanzees ( <i>Pan troglodytes schweinfurthii</i> )

  Evolution Medicine and Public Health · 2025-01-01

  articleOpen access

  Background and Objectives: Understanding health and aging in one of our closest relatives, wild chimpanzees, provides key insights into the evolutionary origins of human disease risk. In humans, females often experience higher rates of disease than men despite having longer lifespans. Here we examine age- and sex- related patterns of health burdens in three communities of wild chimpanzees to investigate whether males exhibit health disadvantages, as predicted by life history trade-offs, or whether females exhibit health disadvantages in line with the health-survival paradox. Methodology: We analyzed 16 years of observational health data from the Kasekela and Mitumba communities of Gombe National Park, Tanzania, and the Kanyawara community of Kibale National Park, Uganda. We recorded clinical signs of respiratory illness, diarrhea, and injuries, along with annual cumulative health signs. We used generalized linear mixed models to examine the effects of sex and age on these measures while controlling for community differences and annual and seasonal patterns. Results: Respiratory clinical signs increased with age, but there were no sex differences. Males exhibited significantly increased likelihood of injuries and diarrhea with peaks in middle-aged years, and higher cumulative health burdens than females throughout adulthood. Conclusions and Implications: Our findings align with predictions from life history theory, suggesting that males prioritize reproductive effort over somatic maintenance, leading to greater health risks. The absence of a male-female health survival paradox in chimpanzees suggests that this pattern in humans is a derived trait, shaped by sociocultural, lifestyle, and environmental factors. These results highlight the importance of cross-species comparisons in understanding the evolution of health and aging.

  PublisherOA PDFDOI

• Wild Chimpanzees (<i>Pan troglodytes schweinfurthii</i>) Use Tools to Access Out of Reach Water

  American Journal of Primatology · 2025-04-01 · 2 citations

  articleOpen access

  The use of tools to drink water is well-documented in wild chimpanzees, but the specific function of this behavior is unclear. Here we use a large data set of drinking behaviors spanning 14 years of observation from the Kanyawara community of chimpanzees living in Kibale National Park, Uganda, to test two possible functions of leaf-sponges and other drinking tools. On the one hand, chimpanzees may use tools to access water that is hard to reach, which predicts that chimpanzees will preferentially use tools to drink at tree holes and crevices compared to all other locations. Conversely, chimpanzees may use these tools to filter stagnant water, in which case they would use tools more often at holes and puddles compared to running water sources (e.g., streams). We compared both likelihood of using a tool to drink at different locations, as well as overall rates of drinking, and found chimpanzees in this community most often drink from streams without tools. However, when they do use tools, they preferentially do so to drink at tree holes. Given known age and sex effects on tool use in chimpanzees, we also examined demographic variation in drinking tool use to understand the emergence of this behavior. While females use tools more often than males overall-in part driven by differences in drinking rates at different locations-both males and females use tools more frequently at tree holes than other locations when they do drink there. Finally, comparisons by age indicate that this selectivity strengthens over development with older chimpanzees showing a more pronounced effect of using tools more often at tree holes, suggesting that younger chimpanzees may exhibit exploratory tool use behavior. These results pinpoint the specific function of tool use during drinking and further suggest that even simple tools may require learning for use in appropriate contexts.

  PublisherOA PDFDOI

• Selective social tolerance drives differentiated relationships among wild female chimpanzees

  Animal Behaviour · 2024-09-16 · 7 citations

  articleOpen access

  Strong, affiliative bonds often function to facilitate social competition through cooperative defence of resources, but the benefits of social bonds may be low when direct competition is less intense or less beneficial. In such cases, one possible outcome is that relationships are weak and undifferentiated. Alternatively, negotiating stable, selectively tolerant relationships may be a strategy to mitigate the costs and risks of sharing space when direct competition is undesirable. We investigated dyadic social tolerance among wild adult female chimpanzees, who engage in low rates of affiliation and aggression amongst one another. While females associate with one another at different rates, these patterns could reflect shared patterns of behaviour (e.g., ranging) rather than social preference or variation in relationship quality. We first determined whether patterns of dyadic spatial association (five-meter proximity) were differentiated and stable over time. To assess whether dyadic spatial association reflected preference and variation in social tolerance, we tested whether spatial association was actively maintained by waiting and following behaviour, and associated with decreased aggression and increased cofeeding. Spatial associations were differentiated, and stronger associations were more stable. Frequent associates used following and waiting behaviour to actively maintain associations. Association positively predicted time cofeeding and negatively predicted aggression. These patterns were true among related and unrelated dyads. Among unrelated females, dyads with stronger associations maintained proximity more mutually. This study highlights social tolerance as a stable relationship attribute that can predict and explain patterns of behaviour and social network structure, distinct from, or in the absence of, affiliation.

  PublisherDOI

• Apparent Stasis of Endocranial Volume in Two Chimpanzee Subspecies

  American Journal of Biological Anthropology · 2024-12-24 · 1 citations

  articleOpen access1st authorCorresponding

  OBJECTIVES: Self-domestication theory and preliminary data suggest that western chimpanzees (Pan troglodytes verus) could have smaller brains than eastern chimpanzees (P. t. schweinfurthii), but no large-scale studies of chimpanzee endocranial volume (ECV) have tested this. This study compares ECV of wild adult P. t. verus and P. t. schweinfurthii, along with femoral head diameter (FHD; an index of body size), bizygomatic breadth (BZB) and palate length (PAL). MATERIALS AND METHODS: Adult crania of P. t. schweinfurthii (60 females, 90 males, from Uganda and Democratic Republic of Congo) and P. t. verus (43 females, 37 males, from Liberia and Ivory Coast) were sampled. ECV was measured using 3 mm diameter glass beads, and FHD, PAL, and BZB with digital calipers. Quantities of interest were estimated using Bayesian inference. RESULTS: No meaningful differences were found between subspecies on average in ECV, FHD, or the relationship between ECV and FHD. Within countries and subspecies, ECV varied widely among individuals, partly because males had higher ECV on average than females. When sex was controlled for, ECV was unrelated to FHD. Within subspecies there was no evidence of meaningful differences in average ECV among countries. PAL was the only measure that differed between subspecies on average, being shorter in P. t. verus females. DISCUSSION: Current data show that within sexes, mean ECV is similar between P. t. verus and P. t. schweinfurthii. This suggests that average brain size in chimpanzees has remained unchanged for ~0.7 million years, in contrast to orangutans (Pongo) and humans.

  PublisherOA PDFDOI

• Christophe Boesch (1951–2024), primatologist and chimpanzee champion

  Nature · 2024-03-01

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• Language likely promoted peace before 100,000 ya

  Behavioral and Brain Sciences · 2024-01-01

  article1st authorCorresponding

  Abstract Based on evidence of selection against alpha-male behavior in the earliest Homo sapiens , I suggest that by 300,000 ya (years ago) language would have been sufficiently sophisticated to contribute to peacemaking between groups. Language also influenced the social landscape of peace and war, and groups' ability to form coalitions.

  PublisherDOI

• Age-related reproductive effort in male chimpanzees: terminal investment or alternative tactics?

  Animal Behaviour · 2024-05-07 · 4 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

Recent grants

• Collaborative Research: SEI: Spatio-temporal Data Analysis Techniques for Behavioural Ecology

  NSF · $128k · 2004–2008

• Endocrine Aspects of Aggression and Dominance in Chimpanzees

  NSF · $216k · 1998–2001

• Doctoral Dissertation Improvement: Cognitive Development in Bonobos and Chimpanzees

  NSF · $15k · 2009–2010

• Ecology and Endocrinology of Chimpanzee Aggression

  NSF · $299k · 2004–2010

• Biodemography of Aging in Wild Chimpanzees

  NIH · $2.3M · 2015–2021

Frequent coauthors

• Zarin Machanda

  Tufts University

  195 shared

• Martin N. Muller

  187 shared

• Melissa Emery Thompson

  Kibale Chimpanzee Project

  177 shared

• Emily Otali

  121 shared

• Tony L. Goldberg

  University of Wisconsin Health

  85 shared

• Colin A. Chapman

  George Washington University

  63 shared

• Erik J. Scully

  National Geospatial-Intelligence Agency

  44 shared

• T.E. Pappas

  University of Wisconsin–Madison

  40 shared

Labs

• Kibale Chimpanzee ProjectPI

Education

• Ph.D., Biological Anthropology

  Harvard University

  1977

• M.A., Biological Anthropology

  Harvard University

  1973

• B.A., Anthropology

  University of California, Santa Barbara

  1969