Ryne A. Palombit


Research Interests    Teaching & Course Syllabi Publications Postdocs & Graduate Students

© Ryne A. Palombit     © Ryne A. Palombit  

"Friendships" in chacma baboons of the Okavango Delta, Botswana (left) & olive baboons of Laikipia, central Kenya (right)

Department of Anthropology
131 George Street
Rutgers University
New Brunswick, New Jersey 08901-1414
Phone: (848) 932-9275
FAX: (732) 932-1564

Director, Center for Human Evolutionary Studies

Email: rpalombit@anthropology.rutgers.edu

Office: 001 Biological Sciences Building, Douglass Campus

Office Hours Spring 2014 Semester: Monday 2:30 - 3:30 pm, Thursday 2:30 -3:30 pm

Research Interests

I am interested in understanding how the extraordinary diversity of social and mating strategies in animals (both human and nonhuman) has evolved.  My current interests focus on a feature of primate biology that largely differentiates these animals from most other mammals: cohesive social bonds between adult males and females persisting beyond estrus.  I use the comparative approach and field experiments to understand the behavioral and ecological bases of variation in male-female social relationships.  I have studied monogamous pair bonds in wild white-handed gibbons (Hylobates lar) and siamang (H.syndactylus) in northern Sumatra, Indonesia, and conducted short-term research on titi monkeys (Callicebus moloch) and red-bearded saki monkeys (Pithecia aequatorialis) in the upper Amazon of Ecuador.   Currently, I direct "Project Papio, a study "friendships" in chacma baboons in Okavango Delta, Botswana and in olive baboons at my field site in Laikipia, Kenya (photos above).

PROJECT PAPIO: Comparative Study of Infanticide and Anti-Infanticide Strategies in Baboons

I am currently conducting a long-term comparative study of chacma baboons (Papio hamadryas ursinus) in Botswana and olive baboons (Papio hamadryas anubis) in central Kenya.  The aim is to understand the evolution of male infanticide and female counter-strategies to infanticide. Of particular interest are the affiliative bonds between males and lactating females, known as "friendships."  Our data suggest that this social relationship functions as a deterrent to sexually selected infanticide in chacma baboons, which accounts for at least 37% of infant mortality.  In East African olive baboons, however, male infanticide occurs rarely, and yet heterosexual friendships develop just as reliably.  This difference is just one of numerous social features distinguishing chacma baboons from their East African cousins (e.g., lack of male-male coalitions, apparently greater sexual monopolization of estrus females by high-ranking males, enhanced territoriality).  I am studying variation within and between both populations of baboons, collecting genetic, experimental, and observational data that will clarify the causal and functional bases of sexually selected infanticide and heterosexual bonds in a multi-male social setting.

Collaborators in this project include Dr. Anthony di Fiore (Anthropology, New York University) and Dr. Joseph Lorenz (Central Washington University) who are conducting genetic analyses, and Dr. Dorothy Cheney (Biology, University of Pennsylvania) and Dr. Robert Seyfarth (Psychology, University of Pennsylvania) for the Botswama component.  My research is supported by grants from the National Science Foundation, the L.S.B. Leakey Foundation, the Wenner-Gren Foundation, the Center for Human Evolutionary Studies, and Rutgers University.  The research is sponsored by the National Museums of Kenya and the Institute of Primate Research (Nairobi, Kenya).

PhD Graduate Students:

• Marc Shur obtained his PhD in 2008.  The Socioendocrinology of "Friendship" Between Adult Male and Lactating Female Baboons (Funded by L.S.B. Leakey Foundation, Wenner-Gren Foundation, Fulbright IIE Fellowship).  Dr. Shur is currently Associate Professor at Berkeley College, New York City, New York.

• Luca Morino obtained his PhD in 2012.  Behavioral Endocrinology of Wild Male Siamangs (Symphalangus syndactylus) (funded by National Science Foundation, Wenner-Gren Foundation).   Dr. Morino is currentlly a postdoctoral researcher at the Primate Research Institute, Kyoto Japan.

• Nancy Moinde (M.Sc., Biology, University of Cape Town) is a recipientois ed hbf the L.S.B. Leakey Baldwin Fellowship and the Wenner-Gren Professional Development Fellowship to support her graduate studies at Rutgers.  She has completed her field her at my field site in Kenya and is currently conducting data analysis and writing her dissertation.  She studied baboon socioecology and baboon-human conflict.  (Funded by NSF Doctoral Dissertation Improvement Grant, Wenner-Gren Foundation, and L.S.B. Leakey Foundation)

• Emily Aronoff (B.A. Anthropology, George Washington University) is currently conducting her disseration resarch at my field site in Kenya.  She has completed her field study of kinship in juvenile baboons and is currently doing data analysis and writing her dissertation.  (Funded by NSF Doctoral Dissertation Improvement Grant, L.S.B. Leakey Foundation, Fulbright IIE Fellowship).

• Stan Kivai (M.Sc. in Biology, Addis Ababa University) will be commencing his doctoral dissertation research on feeding ecology of the Tana River Mangabey.

• Alex Pritchard (M.Sc. Primate Behavior, Central Washington University)
has just arrived in the program and will be commencing pilot research in the summer of 2012.

Postdoctoral Research Associates:

• Akiko Matsumoto-Oda (PhD, Kyoto University) studied the relationship between "friendships" and male-infant bonds among olive baboons in Kenya.  She is currently on the faculty of Okinawa University.

• Alban Lemasson (PhD, University of Rennes) is studied vocal communication in the context of heterosexual "friendships" in olive baboons.  He is currently on the faculty of the University of Rennes.

Teaching Interests
(courses taught)

Undergraduate Courses:

Life of Primates (Anthro 212) (
Course Description)
Primate Behavioral Ecology (Anthro 348)
Primatology & Human Evolution (Anthro 350)
Primate Cognition (Anthro 402)

Graduate Seminars:

Biology of Social Bonds (Anthro 563)
Primate Ecology & Social Behavior (Anthro 568)
Sex Differences & Sexual Selection in Primates (Anthro 569)
Methods in Field Primatology  (Anthro 574))

Editorial Board

Primates (Editorial Advisory Board, 2003 - current)

African Primates: Journal of the Africa Section of the IUCN/SSC Primate Specialist Group (Editorial Committee)

American Journal of Primatology
(Associate Editor, 1999-2004)



Mitani, J.C., Call, J.P., Kappeler, P.M., Palombit, R.A., & Silk, J.B.  (editors).  2012.  Evolution of Primate Societies.  Chicago University Press, Chicago.

Selected Publications:

Palombit, R.A.   in press.   Sexual conflict in nonhuman primates.  Advances in the Study of Behavior.

Palombit, R.A.  in press.  The sexual conflict of infanticide.   In: Sexual Conflict, Cold Spring Harbor Perspectives in Biology (W.R. Rice & S. Gavrilets, eds.), Cold Spring Harbor Press, New York.

Palombit, R.A.  in press.  Infanticide.  In: Encyclopedia of Human Sexuality (P. Whelehan & A. Bolin, eds.), Wiley-Blackwell, New York.

Palombit, R.A.  in press. Olive baboon (Papio anubis).  In: All the World's Primates (N. Rowe, ed).  Pogonias Press, Charlestown, Rhode Island.

Danish, L.M. & Palombit, R.A.  2014.  “Following,” an alternative mating strategy used by male olive baboons (Papio hamadryas anubis): Quantitative behavioral and functional description.  International Journal of Primatology,  DOI 10.1107/s10764-013-9743-3.

Palombit. R.A.  2013.  Papio anubis — olive baboon.  In: Mammals of Africa. Vol. II. Primates. (T.M. Butynski, J. Kingdon, & J. Kalina, eds), pp. 233-239, Bloomsbury, London.

Palombit, R.A.  2012.   Infanticide: Male strategies and female counterstrategies.  In: Evolution of Primate Societies (J.C. Mitani, J.P. Call, P.M. Kappeler, R.A. Palombit, J.B. Silk, eds.), pp. 432-468.  Chicago University Press.  Chicago.

Palombit, R.A.  2010.  Conflict (and bonding) between the sexes.  In: Mind the Gap—Tracing the Origins of Human Universals (P.M. Kappeler & J.B. Silk, editors), pp. 53-84.  Springer, Berlin. [pdf]

Palombit, R.A. 2009.  Friendships with males: A female counterstrategy to infanticide in the Okavango chacma baboons.  In: Sexual Coercion in Primates and Humans: An Evolutionary Perspective On Male Aggression Against Females, (M.N. Muller & R.W. Wrangham, eds.), pp. 377-409.  Harvard University Press, Cambridge, Massachusetts. [pdf, 532KB]

Lemasson, A., Palombit, R.A. & Jubin, R.  2008.  Friendships between males and lactating females in wild olive baboons: Observations and call playback experiments.  Behavioral Ecology & Sociobiology, 67:1027-1035.  [pdf, 220KB]

Palombit, R.A.  2008.  Primates.  International Encylopedia of the Social Sciences, 2nd edition, (W.A. Darity, ed), vol. 6, pp. 459-462.   Macmillan / Thomas Gale, Detroit, Michigan.

Lemasson, A., Palombit, R.A. & Jubin, R.  2007.  Is friendship between adult males and lactating females a counter-strategy to infanticide?  Observations and playback experiments in Kenyan olive baboons.  Folia Primatologica, 78:202.

Shur, M.D., Palombit, R.A. & Whitten, P.L.  2008.  Protection from male versus female harassment: Association between glucocorticoid concentrations and friendship in wild lactating olive baboons (Papio hamadryas anubis) in Laikipia, Kenya.  American Journal of Primatology, 70 (S1):28.  Published Abstract.

Shur, M.D., Palombit, R.A. & Whitten, P.L.  2008.  Association between male testosterone and friendship formation with lactating females in wild olive baboons (Papio hamadryas anubis).  American Journal of Physical Anthropology, 135(S46):193.  Published Abstract.

Cheney, D.L., Seyfarth, R.M., Fischer, J., Beehner, J., Bergman, T., Johnson, S.E., Kitchen, D.M., Palombit, R.A., Rendall, D. & Silk, J.B.  2006.  Reproduction, mortality, and female reproductive success in chacma baboons of the Okavango Delta, Botswana.  In: Reproduction and Fitness in Baboons: Behavioral, Ecological, and Life History Perspectives, (L. Swedell & S.R. Leigh, eds.), pp. 147-176.  Springer, New York.

Cheney, D.L., Seyfarth, R.M.,  Fischer, J., Beehner, J., Bergman, Johnson, S.E., Kitchen, D., Palombit, R.A., Rendall, D., and Silk, J.B. 2004.  Factors affecting reproduction and mortality among baboons in the Okavango Delta, Botswana.  International Journal of Primatology, 25:401-428. [pdf] [216 KB]

Palombit, R.A. 2003. Male infanticide in savanna baboons: Adaptive significance and intraspecific variation. In: Sexual Selection and Reproductive Competition in Primates: New Perspectives and Directions (C.B. Jones, ed.), pp.  367-412. American Society of Primatologists. [pdf, 884KB]

Palombit, R.A. 2003. ‘Friendship’ behavior as a reproductive strategy in savanna baboons: Intraspecific variation.  American Journal of Physical Anthropology, Supplement 36:163-164.

Palombit, R.A. 2001.  Why primates kill their young: Incidences of infanticide in monkey and ape species.  In: The Encyclopedia of Mammals, 2nd edition (D.W. MacDonald, editor), pp. 392-393.  Oxford University Press.  London.

Palombit, R.A., Cheney, D.L., and Seyfarth, R.M.  2001. Female-female competition for male "friends" in wild chacma baboons (Papio cynocephalus ursinus).  Animal Behaviour, 61:1159-1171.  [pdf, 196 KB]

Palombit, R.A.  2000.  Infanticide and the evolution of male-female bonds in animals. In: Infanticide by Males and Its Implications (C.P. van Schaik and C.R. Janson, eds.), pp. 239-268.  Cambridge University Press, Cambridge. [pdf, 292 KB]

Palombit, R.A., Cheney, D.L., Fischer, J., Johnson, S., Rendall, D., Seyfarth, R.M, and Silk, J.B.  2000.  Male infanticide and infant defense in chacma baboons. In: Infanticide by Males and Its Implications (C.P. van Schaik and C.R. Janson, eds.), pp. 123-152.  Cambridge University Press, Cambridge. [pdf, 308 KB]

Cohen, M., Parr, L., & Palombit, R.A.  2000.  Cracking the code: The contextual use of facial expressions by group-housed chimpanzees (Pan troglodytes) and human children (Homo sapiens).  American Journal of Primatology, 51(S1):52.

Palombit, R.A.  1999.  Infanticide and the evolution of pair bonds in nonhuman primates.  Evolutionary Anthropology, 7:117-129. [pdf, 128 KB]

Palombit, R.A., Seyfarth, R.M., and Cheney, D.L.  1999.  Male grunts as mediators of interaction with females in wild chacma baboons (Papio cynocephalus ursinus).  Behaviour, 136:221-242. [pdf] [1.7 MB]

Wich, S.A., Steenbeek, R., Sterck, E.H.M., Palombit, R.A., and Usman, S. 1999.  Tree mortality and recruitment in an Indonesian rain forest.  Tropical Biodiversity, 6:189-195.

Palombit, R.A., Seyfarth, R.M., & D.L. Cheney.  1997.  The adaptive value of "friendships" to female baboons: Experimental and observational evidence.  Animal Behaviour, 54:599-614. [pdf] [195 KB]

Palombit, R.A.  1997.  Inter- and intra-specific variation in the diets of sympatric siamang (Hylobates syndactylus) and white-handed gibbons (Hylobates lar).  Folia Primatologica, 68:321-337. [pdf] [1.1 MB]

Palombit, R.A.  1997.  Of neglect and negligence: Conservation, science, and the fate of the red ape.  American Journal of Primatology, 42:61-65. [pdf] [40 KB]

Palombit, R.A.  1996.  Pair bonds in monogamous apes: A comparison of the siamang (Hylobates syndactylus) and the white-handed gibbon (Hylobates lar). Behaviour, 133:321-356. [pdf] [2.3 MB]

Palombit, R.A.  1996.  The Siamang and White-Handed Gibbon. In: Leuser: A Sumatran Sanctuary (C. P. van Schaik and J. Supriatna, eds.), pp. 269-280.  Yayasan Bina Sains Hayati Indonesia, Depok, Indonesia.

Cheney, D.L., R.M. Seyfarth, & R.A. Palombit.  1996.  The function and underlying mechanisms of baboon 'contact' barks. Animal Behaviour, 52:507-518. [pdf] [262 KB]

Palombit, R.A.  1995.  Longitudinal patterns of reproduction in wild female siamang (Hylobates syndactylus) and white-handed gibbons (Hylobates lar).  International Journal of Primatology, 16:739-760.  [pdf]

Palombit, R.A.  1994.  Dynamic pair bonds in hylobatids: Implications regarding monogamous social systems. Behaviour, 128:65-101.  [pdf] [2.4 MB]

Palombit, R.A.  1994.  Extra-pair copulations in a monogamous ape. Animal Behaviour, 47:721-723. [pdf] [135 KB]

Palombit, R.A.  1993.  Lethal territorial aggression in a monogamous primate. American Journal of Primatology, 31:311-318.

Grether, G.F., R.A. Palombit, and P.S. Rodman.  1992.  Gibbon foraging decisions and the marginal value model. International Journal of Primatology, 13:1-18.

Palombit, R.A.  1992.  A preliminary study of vocal communication in wild long-tailed macaques (Macaca fascicularis). I. Vocal repertoire and call emission. International Journal of Primatology, 13:143-182. [pdf] [3.6 MB]

Palombit, R.A.  1992.  A preliminary study of vocal communication in wild long-tailed macaques (Macaca fascicularis). II. Potential of calls to regulate intragroup spacing. International Journal of Primatology, 13:183-207.  [pdf] [2.2 MB]

© R.A. Palombit

"Pair Bond" in wild Mueller's Gibbons (Hylobates muelleri)

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