Ryne Palombit's research focuses on the extraordinary diversity of social and mating strategies in animals (both human and nonhuman), and how those strategies have evolved. His 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. He uses the comparative approach and field experiments to understand the behavioral and ecological bases of variation in male-female social relationships. He has 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, he directs "Project Papio, a study "friendships" in chacma baboons in Okavango Delta, Botswana and in olive baboons at his field site in Laikipia, Kenya.
Prof. Ryne Palombit has published with his collaborators this year Evolution of Primate Societies (University of Chicago Press). Many years in the making, the new book complies 32 chapters by 44 leading authorities in the field. They provide an up‑to‑date synthesis of the current state of understanding of primate behavioral ecology, organized around four major adaptive problems primates face as they grow up in a difficult and dangerous world, find mates and rear offspring, negotiate complex social worlds, and employ cognitive strategies for coping with life's challenges. Chapters on human behavior at the end of each section is one novel aspect of the book that reminds us what we can learn about ourselves through cutting edge research on nonhuman primates.
Project PAPIO: Comparative Study of Infanticide and Anti-Infanticide Strategies in Baboons
Dr. Palombit is 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." His 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. Dorothy Cheney (Biology, University of Pennsylvania) and Dr. Robert Seyfarth (Psychology, University of Pennsylvania) for the Botswama component, and Dr. Clifford Jolly (Anthropology, New York University), Dr. Anthrony di Fiore (NYU) and Joseph Lorenz (Central Washington University) who are conducting genetic analyses. Dr. Palombit's 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.
Palombit, R.A. in press. Infanticide. In: Encyclopedia of Human Sexuality (P. Whelehan & A. Bolin, eds.), Wiley-Blackwell, New York.
Danish, L.M. & Palombit, R.A. in press. "Following:" An alternative mating strategy used by male olive baboons (Papio hamadryas anubis): Quantitative behavioral and functional description. International Journal of Primatology.
Danish, L.M. & Palombit, R.A. in press. Male olive baboon (Papio hamadryas anubis) "followers" incur time, but not energetic costs. Behaviorial Ecology & Sociobiology.
Palombit, R.A. in press. Olive baboon (Papio anubis). In: All the World's Primates (N. Rowe, ed). Charlestown, Rhode Island. Pogonias Press.
Mitani, J.C., Call, J., Kappeler, P.M., Palombit, R.A., and Silk, J.B., editors. 2012. Evolution of Primate Societies. Chicago, University of Chicago Press.
Palombit, R.A. 2010. Conflict and bonding between the sexes in primates. In: Mind the Gap: Tracing the Origin of Human Universals (P.M. Kappeler & J.B. Silk, editors), pp. 53-84. Berlin, Springer.
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.
Palombit, R.A. 2013. Papio anubis, Olive baboon (Anubis Baboon). In: Mammals of Africa vol. II Primates, (T.M. Butynski, J. Kingdon & J. Kalina, eds.), pp. 233-239. Bloomsbury, London.
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.
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.
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. Leight, 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.
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]