Anne E Pusey
  • Anne E Pusey

  • Professor, Chair, and James B. Duke Professor
  • Evolutionary Anthropology
  • 101F Biological Sciences Building
  • Campus Box 90383
  • Phone: (919) 684-1848
  • Fax: (919) 684-8542
  • Curriculum Vitae
  • Overview

    I am interested in understanding the evolution of sociality, social structure, and the patterns of competition, cooperation and social bonds in animal species, including humans. Most of my work has focused on social mammals: lions and chimpanzees. For the last twenty years I have worked almost exclusively on the long term Gombe chimpanzee project. I have gathered the data from this study into an archive, currently housed at Duke, and I oversee the computerization of systematically collected daily data, incorporating this and related material into a relational database. I also advise on the ongoing field study at Gombe, and advise students working there. Combined analysis of the long-term data and focused new data collection in the field enables study of a wide variety of questions. Current projects in my research group include studies of female social relationships and female settlement patterns, and the importance of alliances in males. We also participate in collaborative work with colleagues at a number of other institutions on studies of life history, personality, and health, including studying the natural history of SIVcpz.
  • Specialties

    • Primate Ecology
    • Cognitive Evolution
  • Areas of Interest

    Behavioral ecology; parent-offspring interaction; sex differences in development; dispersal patterns; mating systems.
  • Education

      • Ph.D.,
      • Ethology,
      • Stanford University,
      • 1978
      • B.A. (M.A.),
      • Zoology,
      • Oxford University,
      • 1970
  • Awards, Honors and Distinctions

      • Fellow of the Animal Behavior Society,
      • 2013
      • James B. Duke Professor of Evolutionary Anthropology, Duke University,
      • 2010
      • Fellow of the American Academy of Arts and Sciences,
      • 2005
      • McKnight Distinguished University Professor, University of Minnesota,
      • 1999
      • John Simon Guggenheim Fellowship.,
      • 1990
  • Selected Publications

      • AE Pusey, GW Oehlert, JM Williams, & J Goodall.
      • 2005.
      • The influence of ecological and social factors on body mass of wild chimpanzees.
      • International Journal of Primatology
      • 26:
      • 3-31
      • .
      Publication Description

      The chimpanzees (Pan troglodytes schweinfurthii) of Gombe National Park, Tanzania, were weighed regularly over a period of 33 yr, resulting in 1286 measurements on 31 males and 26 females aged 2–43 yr. Female growth slowed at 10 yr and that of males at 13 yr. Median adult body mass is 39 kg for males and 31.3 kg for females. Body mass varied between years. Chimpanzees were heaviest during a period of frequent banana provisioning. They were also heavier when community range size was large and population density within the range was low. Chimpanzees were heavier in the wet than in the dry season and body mass tracked rainfall in the preceding mo except for May in which mass was anomalously low. Dominance rank is significantly correlated with body mass for females but not males. High-ranking individuals tended to maintain more stable mass. Variability in body mass was greater for young and old individuals than for prime adults.

      • IC Gilby, LE Eberly, L Pintea, & AE Pusey.
      • 2006.
      • Ecological and social influences on the hunting behaviour of wild chimpanzees (Pan troglodytes schweinfurthii).
      • Animal Behaviour
      • 72:
      • 169-180
      • .
      Publication Description

      There has been considerable discussion of the factors that influence the hunting behaviour of male chimpanzees. Explanations invoking social benefits hinge upon the potential for males to share meat with sexually receptive females in exchange for mating (‘meat for sex’), or to share meat with other males in exchange for social support (‘male social bonding’). Ecological factors may also affect hunting: chimpanzees may hunt more frequently (1) in response to food shortages (‘nutrient shortfall’); (2) when energy reserves are high (‘nutrient surplus’); (3) in habitat types with good visibility and increased prey vulnerability; and/or (4) when ecological factors favour cooperative hunting. We used 25 years of data on chimpanzees in Gombe National Park, Tanzania, to examine the relative importance of social and ecological factors in the decision to hunt red colobus monkeys, Colobus badius. The presence of sexually receptive females was associated with a significant decrease in hunting probability, suggesting that males face a trade-off between hunting and mating (‘meat or sex’ rather than ‘meat for sex’). Hunting by specific males did not vary with adult male party size, providing evidence against the male social-bonding hypothesis. After controlling for the effects of party size, diet quality was not associated with the probability of hunting or hunting successfully. Hunts were more likely to occur and to succeed in woodland and semideciduous forest than in evergreen forest, emphasizing the importance of visibility and prey mobility. Finally, per capita meat availability decreased with adult male party size, suggesting that hunting was not cooperative. These results provide evidence against social explanations for hunting in favour of more simple ecological alternatives.

      • CM Murray, LE Eberly & AE Pusey.
      • 2006.
      • Foraging strategies as a function of season and rank among wild female chimpanzees (Pan troglodytes).
      • Behavioral Ecology
      • 1020-1028
      • .
      Publication Description

      Among mammals, female reproduction is generally thought to be food limited, and dominance should theoretically afford high-ranking females with access to better food resources. Although the importance of dominance rank among female chimpanzees (Pan troglodytes) has been debated in the past, mounting evidence suggests that rank is very important among females (P. t. schweinfurthii) at Gombe National Park, Tanzania. In this study, we investigated the influence of season and dominance rank on female foraging strategies. We found that high-ranking females spent less time foraging and tended to have a narrower diet breadth and higher diet quality than subordinate females. In this way, subordinate female foraging strategies were consistent with how females in general adapted to periods of food scarcity. The results of this study therefore suggest that low-ranking females may face persistent "food scarcity" as a result of interference food competition. We also provide evidence that subordinates may forage less efficiently because they occupy lower quality habitats or avoid associating with dominant females in shared areas.

      • CM Murray, SV Mane & AE Pusey.
      • 2007.
      • Dominance rank influences female space use in wild chimpanzees (Pan troglodytes schweinfurthii: Towards an ideal despotic distribution.
      • Animal Behaviour
      • 74:
      • 1795-1804
      • .
      Publication Description

      Studies from many different taxa have demonstrated that dominance rank greatly influences individual space use. While the importance of dominance among female chimpanzees, Pan troglodytes, was debated in the past, mounting evidence now shows that rank is very important. In particular, rank has been shown to influence body mass, foraging strategies, association patterns, and ultimately, reproductive success. In this study, we investigated how rank influenced female space use among chimpanzees, P.t. schweinfurthii, at Gombe National Park, Tanzania. Analysing 10 years of data, we found that new immigrants used areas away from dominant females, and that subordinates had lower site fidelity. We also found that high-ranking females had smaller core areas and that this size difference was pronounced during periods of food scarcity when food competition is highest. These patterns suggest that dominant females outcompete subordinates, forcing them to settle elsewhere, range more widely, and shift their space use across time.

      • AE Pusey, L Pintea, ML Wilson, S Kamenya, J Goodall.
      • 2007.
      • The contribution of long-term research at Gombe National Park to chimpanzee conservation..
      • Conservation biology : the journal of the Society for Conservation Biology
      • 21:
      • 623-34
      • .
      Publication Description

      Long-term research projects can provide important conservation benefits, not only through research specifically focused on conservation problems, but also from various incidental benefits, such as increased intensity of monitoring and building support for the protection of an area. At Gombe National Park, Tanzania, long-term research has provided at least four distinct benefits to wildlife conservation. (1) Jane Goodall's groundbreaking discoveries of chimpanzee (Pan troglodytes) tool use, hunting, and complex social relationships in what was then a game reserve drew attention to the area and created support for upgrading Gombe to national park status in 1968. (2) The highly publicized findings have earned Gombe and Tanzania the attention of a worldwide public that includes tourists and donors that provide financial support for Gombe, other parks in Tanzania, and chimpanzee conservation in general. (3) Crucial information on social structure and habitat use has been gathered that is essential for effective conservation of chimpanzees at Gombe and elsewhere. (4) A clear picture of Gombe's chimpanzee population over the past 40 years has been determined, and this has helped identify the greatest threats to the viability of this population, namely disease and habitat loss outside the park. These threats are severe and because of the small size of the population it is extremely vulnerable. Research at Gombe has led to the establishment of conservation education and development projects around Gombe, which are needed to build local support for the park and its chimpanzees, but saving these famous chimpanzees will take a larger integrated effort on the part of park managers, researchers, and the local community with financial help from international donors.

      • M Emery Thompson, JH Jones, AE Pusey, S Brewer-Marsden, J Goodall, D Marsden, T Matsuzawa, T Nishida, V Reynolds, Y Sugiyama, RW Wrangham.
      • 2007.
      • Aging and fertility patterns in wild chimpanzees provide insights into the evolution of menopause..
      • Current biology : CB
      • 17:
      • 2150-6
      • .
      Publication Description

      Human menopause is remarkable in that reproductive senescence is markedly accelerated relative to somatic aging, leaving an extended postreproductive period for a large proportion of women. Functional explanations for this are debated, in part because comparative data from closely related species are inadequate. Existing studies of chimpanzees are based on very small samples and have not provided clear conclusions about the reproductive function of aging females. These studies have not examined whether reproductive senescence in chimpanzees exceeds the pace of general aging, as in humans, or occurs in parallel with declines in overall health, as in many other animals. In order to remedy these problems, we examined fertility and mortality patterns in six free-living chimpanzee populations. Chimpanzee and human birth rates show similar patterns of decline beginning in the fourth decade, suggesting that the physiology of reproductive senescence was relatively conserved in human evolution. However, in contrast to humans, chimpanzee fertility declines are consistent with declines in survivorship, and healthy females maintain high birth rates late into life. Thus, in contrast to recent claims, we find no evidence that menopause is a typical characteristic of chimpanzee life histories.

      • AE Pusey, CM Murray, W Wallauer, ML Wilson, E Wroblewski & J Goodall.
      • 2008.
      • Severe Aggression among Female Pan troglodytes schweinfurthii at Gombe National Park, Tanzania.
      • International Journal of Primatology
      • 29:
      • 949-973
      • .
      Publication Description

      Aggression is generally more severe between males than between females because males gain greater payoffs from escalated aggression. Males that successfully defeat rivals may greatly increase their access to fertile females. Because female reproductive success depends on long-term access to resources, competition between females is often sustained but low key because no single interaction leads to a high payoff. Nonetheless, escalated aggression can sometimes immediately improve a female’s reproductive success. Resisting new immigrants can reduce feeding competition, and infanticide of other females’ young can increase a female’s access to resources. East African chimpanzees live in fission-fusion communities in which females occupy overlapping core areas. Growing evidence indicates that reproductive success correlates with core area quality, and that females compete for long-term access to core areas. Here we document 5 new cases of severe female aggression in the context of such competition: 2 attacks by resident females on an immigrant female, a probable intracommunity infanticide, and 2 attacks on a female and her successive newborn infants by females whose core areas overlapped hers. The cases provide further evidence that females are occasionally as aggressive as males. Factors influencing the likelihood and severity of such attacks include rank and size differences and the presence of dependable allies. Counterstrategies to the threat of female aggression include withdrawing from others around the time of parturition and seeking male protection. We also discuss an unusual case of a female taking the newborn infant of another, possibly to protect it from a potentially infanticidal female.

      • CM Murray, IC Gilby, SV Mane & AE Pusey.
      • 2008.
      • Male chimpanzees inherit maternal ranging patterns.
      • Current Biology
      • 18:
      • 20-24
      • .
      • JM Williams, EV Lonsdorf, ML Wilson, J Schumacher-Stankey, J Goodall, AE Pusey.
      • 2008.
      • Causes of death in the Kasekela chimpanzees of Gombe National Park, Tanzania..
      • American journal of primatology
      • 70:
      • 766-77
      • .
      Publication Description

      Understanding the rates and causes of mortality in wild chimpanzee populations has important implications for a variety of fields, including wildlife conservation and human evolution. Because chimpanzees are long-lived, accurate mortality data requires very long-term studies. Here, we analyze 47 years of data on the Kasekela community in Gombe National Park. Community size fluctuated between 38 and 60, containing 60 individuals in 2006. From records on 220 chimpanzees and 130 deaths, we found that the most important cause of mortality in the Kasekela community was illness (58% of deaths with known cause), followed by intraspecific aggression (20% of deaths with known cause). Previous studies at other sites also found that illness was the primary cause of mortality and that some epidemic disease could be traced to humans. As at other study sites, most deaths due to illness occurred during epidemics, and the most common category of disease was respiratory. Intraspecific lethal aggression occurred within the community, including the killing of infants by both males and females, and among adult males during the course of dominance-related aggression. Aggression between communities resulted in the deaths of at least five adult males and two adult females in the Kasekela and Kahama communities. The frequency of intercommunity violence appears to vary considerably among sites and over time. Intercommunity lethal aggression involving the Kasekela community was observed most frequently during two periods. Other less common causes of death included injury, loss of mother, maternal disability, and poaching.

      • EE Wroblewski, CM Murray, BF Keele, JC Schumacher-Stankey, BH Hahn, AE Pusey.
      • 2009.
      • Male dominance rank and reproductive success in chimpanzees, Pan troglodytes schweinfurthii..
      • Animal behaviour
      • 77:
      • 873-885
      • .
      Publication Description

      Competition for fertile females determines male reproductive success in many species. The priority of access model predicts that male dominance rank determines access to females, but this model has been difficult to test in wild populations, particularly in promiscuous mating systems. Tests of the model have produced variable results, probably because of the differing socioecological circumstances of individual species and populations. We tested the predictions of the priority of access model in the chimpanzees of Gombe National Park, Tanzania. Chimpanzees are an interesting species in which to test the model because of their fission-fusion grouping patterns, promiscuous mating system and alternative male mating strategies. We determined paternity for 34 offspring over a 22-year period and found that the priority of access model was generally predictive of male reproductive success. However, we found that younger males had higher success per male than older males, and low-ranking males sired more offspring than predicted. Low-ranking males sired offspring with younger, less desirable females and by engaging in consortships more often than high-ranking fathers. Although alpha males never sired offspring with related females, inbreeding avoidance of high-ranking male relatives did not completely explain the success of low-ranking males. While our work confirms that male rank typically predicts male chimpanzee reproductive success, other factors are also important; mate choice and alternative male strategies can give low-ranking males access to females more often than would be predicted by the model. Furthermore, the success of younger males suggests that they are more successful in sperm competition.

      • BF Keele, JH Jones, KA Terio, JD Estes, RS Rudicell, ML Wilson, Y Li, GH Learn, TM Beasley, J Schumacher-Stankey, E Wroblewski, A Mosser, J Raphael, S Kamenya, EV Lonsdorf, DA Travis, T Mlengeya, MJ Kinsel, JG Else, G Silvestri, J Goodall, PM Sharp, GM Shaw, AE Pusey, BH Hahn.
      • 2009.
      • Increased mortality and AIDS-like immunopathology in wild chimpanzees infected with SIVcpz..
      • Nature
      • 460:
      • 515-9
      • .
      Publication Description

      African primates are naturally infected with over 40 different simian immunodeficiency viruses (SIVs), two of which have crossed the species barrier and generated human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). Unlike the human viruses, however, SIVs do not generally cause acquired immunodeficiency syndrome (AIDS) in their natural hosts. Here we show that SIVcpz, the immediate precursor of HIV-1, is pathogenic in free-ranging chimpanzees. By following 94 members of two habituated chimpanzee communities in Gombe National Park, Tanzania, for over 9 years, we found a 10- to 16-fold higher age-corrected death hazard for SIVcpz-infected (n = 17) compared to uninfected (n = 77) chimpanzees. We also found that SIVcpz-infected females were less likely to give birth and had a higher infant mortality rate than uninfected females. Immunohistochemistry and in situ hybridization of post-mortem spleen and lymph node samples from three infected and two uninfected chimpanzees revealed significant CD4(+) T-cell depletion in all infected individuals, with evidence of high viral replication and extensive follicular dendritic cell virus trapping in one of them. One female, who died within 3 years of acquiring SIVcpz, had histopathological findings consistent with end-stage AIDS. These results indicate that SIVcpz, like HIV-1, is associated with progressive CD4(+) T-cell loss, lymphatic tissue destruction and premature death. These findings challenge the prevailing view that all natural SIV infections are non-pathogenic and suggest that SIVcpz has a substantial negative impact on the health, reproduction and lifespan of chimpanzees in the wild.

      • BF Keele, JH Jones, KA Terio, JD Estes, RS Rudicell, ML Wilson, Y Li, GH Learn, TM Beasley, J Schumacher-Stankey, E Wroblewski, A Mosser, J Raphael, S Kamenya, EV Lonsdorf, DA Travis, T Mlengeya, MJ Kinsel, JG Else, G Silvestri, J Goodall, PM Sharp, GM Shaw, AE Pusey, BH Hahn.
      • 2009.
      • Increased mortality and AIDS-like immunopathology in wild chimpanzees infected with SIVcpz..
      • Nature
      • 460:
      • 515-9
      • .
      Publication Description

      African primates are naturally infected with over 40 different simian immunodeficiency viruses (SIVs), two of which have crossed the species barrier and generated human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). Unlike the human viruses, however, SIVs do not generally cause acquired immunodeficiency syndrome (AIDS) in their natural hosts. Here we show that SIVcpz, the immediate precursor of HIV-1, is pathogenic in free-ranging chimpanzees. By following 94 members of two habituated chimpanzee communities in Gombe National Park, Tanzania, for over 9 years, we found a 10- to 16-fold higher age-corrected death hazard for SIVcpz-infected (n = 17) compared to uninfected (n = 77) chimpanzees. We also found that SIVcpz-infected females were less likely to give birth and had a higher infant mortality rate than uninfected females. Immunohistochemistry and in situ hybridization of post-mortem spleen and lymph node samples from three infected and two uninfected chimpanzees revealed significant CD4(+) T-cell depletion in all infected individuals, with evidence of high viral replication and extensive follicular dendritic cell virus trapping in one of them. One female, who died within 3 years of acquiring SIVcpz, had histopathological findings consistent with end-stage AIDS. These results indicate that SIVcpz, like HIV-1, is associated with progressive CD4(+) T-cell loss, lymphatic tissue destruction and premature death. These findings challenge the prevailing view that all natural SIV infections are non-pathogenic and suggest that SIVcpz has a substantial negative impact on the health, reproduction and lifespan of chimpanzees in the wild.

      • JH Jones, ML Wilson, C Murray, A Pusey.
      • 2010.
      • Phenotypic quality influences fertility in Gombe chimpanzees..
      • The Journal of animal ecology
      • 79:
      • 1262-9
      • .
      Publication Description

      Summary 1. Fertility is an important fitness component, but is difficult to measure in slowly reproducing, long-lived animals such as chimpanzees (Pan troglodytes). 2. We measured fertility and the effect of measured covariates on fertility in a 43-year sample of birth intervals of chimpanzees from the Gombe National Park, Tanzania using Cox proportional hazards regression with individual-level random effects. 3. The birth hazard declined with mothers' age at a rate of 0.84 per year following age at first reproduction. This value is somewhat stronger than previous estimates. 4. Loss of the infant that opened the birth interval increased the birth hazard 134-fold. 5. Birth intervals following the first complete birth interval were shorter than this first interval, while sex of the previous infant had no significant effect. 6. Maternal dominance rank was significant at the P

      • Anne M. Bronikowski, Jeanne Altmann, Diane K. Brockman, Marina Cords, Linda M. Fedigan, Anne Pusey, Tara Stoinski, William F. Morris, Karen B. Strier, and Susan C. Alberts.
      • 2011.
      • Aging in the natural world: Comparative data reveal similar mortality patterns across primates.
      • Science
      • 331,:
      • 1325-1328
      • .
      Publication Description

      Human senescence patterns – late onset of mortality increase, slow mortality acceleration, and exceptional longevity – are often described as unique in the animal world. Using an individual-based dataset from longitudinal studies of wild populations of seven primate species, we show that contrary to assumptions of human uniqueness, human senescence falls within the primate continuum of aging, the tendency for males to have shorter lifespans and higher age-specific mortality than females throughout much of adulthood is a common feature in many, but not all, primates, and the aging profiles of primate species do not reflect phylogenetic position. These findings suggest that mortality patterns in primates are shaped by local selective forces rather than phylogenetic history.

      • Morris WF, Altmann J, Brockman DK, Cords M, Fedigan LM, Pusey AE, Stoinski TS, Bronikowski AM, Alberts SM, Strier KB.
      • 2011.
      • Low Demographic Variability in Wild Primate Populations: Fitness Impacts of Variation, Covariation, and Serial Correlation in Vital Rates..
      • American Naturalist
      • Jan;177(1)::
      • E14-28.
      • .
      Publication Description

      In a stochastic environment, long-term fitness can be influenced by variation, covariation, and serial correlation in vital rates (survival and fertility). Yet no study of an animal population has parsed the contributions of these three aspects of variability to long-term fitness. We do so using a unique database that includes complete life-history information for wild-living individuals of seven primate species that have been the subjects of long-term (22–45 years) behavioral studies. Overall, the estimated levels of vital rate variation had only minor effects on long-term fitness, and the effects of vital rate covariation and serial correlation were even weaker. To explore why, we compared estimated variances of adult survival in primates with values for other vertebrates in the literature and found that adult survival is significantly less variable in primates than it is in the other vertebrates. Finally, we tested the prediction that adult survival, because it more strongly influences fitness in a constant environment, will be less variable than newborn survival, and we found only mixed support for the prediction. Our results suggest that wild primates may be buffered against detrimental fitness effects of environmental stochasticity by their highly developed cognitive abilities, social networks, and broad, flexible diets.

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  • PhD Students

    • Joseph T Feldblum
    • Emily Boehm
      • 2011 - present
    • Kara Walker
      • 2012-present
  • Teaching

    • EVANTH 546S.01
      • PRIMATE SOCIAL EVOLUTION
      • Bio Sci 101D
      • TuTh 10:05 AM-11:20 AM