The Female-Biased Dispersal Patterns In Chimpanzees

Chimpanzees live in fission-fusion groups in which individuals form subgroups that are fluid and flexible (Goodall 1968). Females are the dispersing sex in chimpanzees (Pusey 1980); thus, there is low variation in the degree of relatedness between females in the same community, and the majority of female-female bonds will not be closely related (Vigilant et al. 2001). Most female chimpanzees emigrate at adolescence, between nine and 14 years old (Nishida et al. 2003). Inbreeding avoidance accounts for such dispersal pattern: emigrating females are not likely to be related to other adult females in their new community and the dominance hierarchy is linked to age (with younger immigrant females ranking the lowest) and the status of their offspring (Nishida 1989). …show more content…
2009). Immigrant females are mates for males, but competitors for females (Watts 2012). Resident females often aggressively resist new immigrants; particularly severe aggression involves coalitionary attacks and can result in infanticide (Pusey 2008) Such aggression reduces feeding competition for residents by dissuading immigrants from staying or establishing core areas in good habitat (Kahlengerg et al 2008). Immigrants can reduce harassment by establishing core areas that overlap minimally with those of residents, and by avoiding other females when they give birth (Pusey 2008). Once established, immigrants have more food resources and costs of aggression towards them increase (Murray