Fall/Winter 2010  

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Washington University in
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Department of Anthropology

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Primate Studies

baboon
Kinda baboon (Papio cynocephalus kindae) male, female and infant. Kafue National Park, Zambia. Photo credit: Jane Phillips-Conroy

Primatology is an extremely diverse discipline within physical anthropology, encompassing the study of all aspects of nonhuman primates. Physical anthropology faculty and graduate students in the Department of Anthropology conduct research that spans fossil as well as living primates. Professor Tab Rasmussen works at the intersection of these intellectual paths. He studies fossil primates, teaches a popular survey course on primate biology and behavior, and supervises graduate students who work on fossil primates as well as those studying living primates.

With the recent addition of Crickette Sanz, PhD 2004, to the faculty, the Washington University anthropology department strengthens its reputation as one of the world’s premier programs for primate studies. Sanz joins Robert Sussman, Jane Phillips-Conroy, Tab Rasmussen, and Herman Pontzer to form an exceptional faculty researching a wide range of topics involving living primates.

Assistant Professor Crickette Sanz has been studying the behavioral ecology of the central subspecies of chimpanzee (Pan troglodytes troglodytes) for the past 10 years in the Republic of Congo’s northern Goualougo Triangle. Her research focuses on the variation in chimpanzee social organization and material culture that has been observed in different wild populations. In addition, using remote video cameras, she documents the elaborate tool use of the Goualougo chimpanzees and compares their tool repertoire with those of other chimpanzee populations. Sanz hopes that identifying the factors that lead to intraspecific variation in chimpanzees will help explain some of the primary drivers in the evolution of primate social behavior and ecology. She is also actively involved in chimpanzee conservation through applied conservation research, enhancing the protection of chimpanzee habitats, and the involvement of local people in conservation efforts. Her research also addresses health issues at the interface between wild primates and local human populations. Sanz participated in the discovery of the origin of the world’s deadliest from of human malaria, Plasmodium falciparum, in western lowland gorillas.

Professor Robert Sussman has been studying ring-tailed lemurs (Lemur catta) in Madagascar for over 30 years. He is the co-founder of Beza Mahafaly Reserve, which is part of a cooperative program in research, conservation, education, and development involving Washington University, Yale University, and the University of Madagascar. He has also studied the ecology and social organization of a long-tailed macaque population introduced to the island of Mauritius over 450 years ago, as well as conducted field research in Costa Rica and Guyana. More recently, Sussman has focused on the use of primate studies to understand the evolution of human behavior and the history of physical anthropology.

The research of Professor Jane Phillips-Conroy focuses on long-term study of the hybrid zone between olive and hamadryas baboons (Papio hamadryas, s.l.) in the Awash National Park in Ethiopia. This project is multidisciplinary, involving research in behavioral ecology, genetics, morphology, and neurochemistry. She investigates a range of ecological and behavioral variables to better understand what factors influence population structure. More broadly, Phillips-Conroy is interested in the variation found among baboon species and populations throughout Africa and how this relates to questions of speciation within the genus Papio.

Assistant Professor Herman Pontzer examines the evolutionary history of great apes and humans, focusing on energetics and functional morphology. He uses a combined modeling and experimental approach to test hypotheses about selection pressures shaping metabolic physiology and functional anatomy. His recent work on orangutans suggests that they use less energy, relative to body mass, than nearly any eutharian mammal, including sedentary humans.

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Although this young chimpanzee has not been habituated to human observation, she allows scientists in the Goualougo Triangle to make observations of her behavior. Photo credit: Ian Nichols of National Geographic. Courtesy of Crickette Sanz

With such a strong faculty specializing in primate studies, it is no surprise that department graduate students are researching an extraordinary variety of exciting topics in primatology, including ecology, social behavior and aggression, conservation, the use of Geographic Information Systems (GIS), population genetics, quantitative genetics, and hybridization. Students are involved in studies of prosimians, new world monkeys, old world monkeys, and apes, with field sites all over the world — from Sri Lanka to Peru.

Many primatology graduate students are researching ecological questions, assessing how their primate study subjects use the environment, what food resources they rely on, and how they interact with other species.

For instance, Rajnish Vandercone focuses his research on the comparative ecology of the purple-faced langur (Trachypithecus vetulus) and the hanuman langur (Semnopithecus entellus). His aim is understanding the role of interspecific competition in the resource use patterns of these primates and the mechanisms that enable potential competitors to coexist, as well as the importance of intragroup competition on group size in folivorous primates.

Marc Fourrier studies plant–animal interactions. Specifically, he is interested in analyzing the effect of the western lowland gorilla’s foraging and ranging behaviors on the spatial ecology of the tree species upon which they feed. Using GIS, he has found that these large primates, feeding heavily on fruit during certain months, have the potential to deposit a large number of seeds to favorable sites in a manner that is both quantitatively and qualitatively different than smaller primates and other mammalian and avian dispersers.

Lisa Kelley based her dissertation on a 15-month study she conducted on two troops of Lemur catta in the extreme south of Madagascar. The study seeks to answer four primary research questions: 1) How does the behavioral ecology of the cactus-adapted L. catta compare with L. catta living in gallery forest? 2) Are there any indications that these cactus dwellers suffer in health, nutrition, and reproduction? 3) How important is Opuntia as a dietary resource for these individuals? and 4) What is the significance of the sacred forests in the region?

Chris Shaffer studies the foraging and group cohesiveness of brown-bearded sakis in Guyana. He is specifically interested in the behavioral adaptations that allow this seed-eating primate to avoid intraspecific competition despite group sizes of over 60 animals. Saki ranging patterns are his primary focus. Shaffer is using GIS to quantify saki subgrouping in relationship to the distribution and quality of food resources. He is also interested in combining behavioral ecology research with locally based conservation efforts.

The primary objective of Leandra Luecke’s research is to determine the use of plant resources by Chontal Maya people and howler monkeys (Alouatta pigra) in a mangrove habitat on Pantanos de Centla Biosphere Reserve in Tabasco, Mexico. Within this general objective, she examines topics concerning resource use and the interface between howlers and humans in this location, the response of howlers to the low plant diversity in mangroves, the nutritive and toxic components of available plant materials, as well as human knowledge and uses of mangrove plants, and perceptions of conservation of the flora and fauna in the mangrove.

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The cactus lemurs of Madagascar: Ring-tailed lemurs (Lemur catta) sun on one of their sleeping hedges in the early morning hours. Photo credit: Elizabeth Kelley

Lana Kerker focuses her work on the ranging and feeding behaviors of two sympatric lemur species (Propithecus diadema diadema and Indri indri) at Betampona Nature Reserve in Madagascar. She is also working to refine a predictive habitat suitability model of the reserve for each species. Her dissertation will focus on the indri, particularly their kinship and dispersal in the forest. Kerker will collect behavioral data on radio-collared individuals and incorporate genetic analysis to determine relatedness of individuals.

Several students are focused primarily on the study of primate genetics.

Joe Orkin is examining how geographic boundaries — both human-induced and natural — differentially restrict gene flow in fragmented populations of gibbons and leaf monkeys in the mountains of Yunnan, China. His research will analyze the species structure of the critically endangered black-crested gibbon, providing a population genetic framework for conservation efforts.

Jessica Joganic’s project involves quantifying the variation in craniofacial morphology within a population of baboons, qualifying the underlying genetic architecture, and identifying specific regions of the genome highly correlated with the traits upon which selection may have acted in shaping the primate skull to its environment. She compares these regions among a sample of primates to determine their evolutionary history, answers questions about the relative importance of specific traits for various species, and infers these species’ historical environments.

Two students combine behavioral ecology research with genetics.

Mrinalini Watsa works at the Los Amigos Biological Conservation Concession in the Department of Madre de Dios in Peru on the population genetics of saddleback tamarins (Saguinus fuscicollis weddelli). In addition to describing the relatedness between and within groups in this species, she also documents chimerism and its effects, if any, on affiliative and agonistic behaviors in the context of cooperative breeding.

Using a combination of genetic, phenotypic, and behavioral approaches, Monica Macdonald focuses her research on the study of kinda and gray-footed chacma baboons where they occur at a hybrid zone in southern Kafue National Park, Zambia. Her research will provide an understanding of the population structure of these baboons, as well as new information on the behavioral ecology of kinda baboons. She hopes that her study will also elucidate the extent and patterning of gray-footed and kinda baboon hybridization.

Other students are primarily interested in primate social behavior.

Joshua Marshack centers his research on primate social behavior and the evolution of sociality and cooperation. He studies the Fongoli chimpanzee community in Senegal in his dissertation project, “Affiliative and agonistic social behavior in Pan troglodytes verus.” Through his work, he hopes to challenge the prevailing philosophical and political paradigm that competition and aggression dominate evolution and social life in humans and our closest living relative, the chimpanzee.

Meanwhile, Lisa Guidi’s research deals primarily with differences in behavior exhibited by male and female nonhuman primates. While behavioral differences can be due to ecological and/or social factors, her research focuses mainly on social factors. Her dissertation will investigate the validity of the sexual coercion theory, which states that female-directed aggression by males functions as a means of securing mating opportunities.

Anna Weyher focuses her research on baboon behavior and biology, including social relationships, endocrinology, and disease. She is studying male–female relationships among kinda baboons (Papio cynocephalus kindae) in Zambia using behavioral observation, microsatellite analysis, and endocrinology to explore friendships among her study population.

First-year primatology students Kenny Chiou, Ashley van Batavia, and Melissa Milstein will be developing their dissertation projects in the next year.

“Washington University has been one of the few major centers for primate research for almost 40 years,” Sussman sums up. “We have produced over 50 PhD students and many undergraduate students who continued in primatology for their graduate careers. These include scientists working in field primatology, primate biology, paleontology, and conservation. Many of our students are now leading primatologists and hold positions in universities and conservation organizations around the world.”