In most baboons, females are philopatric, i.e., they typically remain in their natal groups throughout their lives (Hausfater 1975a; Smuts 1985; Hamilton and Bulger 1993). Transfer of females between social groups has been observed in some chacma and yellow baboon populations, but only rarely (Anderson 1981a; Rasmussen 1981; Byrne et al 1987). Thus, groups of related females form the social core of a baboon troop, and female baboons typically reproduce in the group in which they were born.
Male baboons, by contrast, typically leave their natal groups and may transfer between groups several times throughout their lifetime (Hausfater 1975a; Packer 1979a; Smuts 1985; Manzolillo 1986; Alberts and Altmann 1995a; Sapolsky 1996; Charpentier et al 2004). This process of dispersal by male baboons may start when a male is a young subadult (i.e., not yet full body size, canine teeth not yet fully developed), at which point he may leave his natal troop and join other troops on a temporary basis while he decides which troop to ultimately immigrate into. We thus may see male baboons wandering around alone during this dispersal process, which may last several months or more.
The one known exception to this general pattern is the hamadryas baboon, in which females are transferred among one-male units (OMUs) by males, usually coercively (Swedell and Schreier 2009), and males sometimes disperse as well (Sigg et al 1982; Phillips-Conroy et al 1991, 1992; Phillips-Conroy and Jolly 2004). Transfer of females generally occurs within the clan and/or band level of social structure (see Social Organization page) rather than among them, however (Sigg et al 1982; Swedell 2005; Schreier and Swedell 2009; Swedell et al. 2011). Female transfer in hamadryas baboons is thus not analogous to the male transfer seen in other baboons in that females do not always move between ecological units (bands) but often just within the reproductive and social units (OMUs and clans). A combination of behavioral and genetic evidence from several hamadryas populations to date suggests limited bi-sexual dispersal with primarily female-mediated gene flow (Sigg et al 1982; Woolley-Barker 1999; Hapke et al 2001; Hammond et al 2006; Swedell 2005, 2006; Swedell et al. in 2011).
Content contributed by:
Dr Larissa Swedell
|Thanks to the following reviewers:
Dr Susan Alberts
Dr Cliff Jolly
For a more scholarly version of the information on these pages, see:
Swedell, L (2011) African Papionins: Diversity of Social Organization and Ecological Flexibility. IN Primates in Perspective, Second Edition (Campbell CJ, Fuentes A, MacKinnon KC, Bearder SK, Stumpf, RM, eds). New York: Oxford University Press, pp. 241-277.
When using information on these pages, please cite the URL of the specific page from which you acquired the information. For scholarly citations of this material, please cite the above chapter by L. Swedell, available as a pdf by emailing the author. Please credit either this website or the above chapter for any and all use of this material.