Fission-Fusion System
Social Spacing
Female chimpanzee distribution is determined ecologically, and the males surround the females (Richard & Schulman, 1982). Due to evenly spaced food, and female desire to forage, female chimpanzees are very solitary and dispersed. Males are unable to defend these dispersed females so they must band together to defend the territory (Williams, et. al., 2002). Females forage in small, overlapping home ranges while males are considered to have a larger territory encompassing female areas, and all males take part in the defense.
Party System
Chimpanzees live in permanent social groups known as communities with subgroups
called parties (Williams, et. al., 2002). A party is a collection of independently
associating individuals showing coordination in behavior. These smaller parties
are a more stable environment providing opportunity for other social strategies,
such as alliances and mating opportunities. Party size can vary, but the
smallest parties are traveling parties. Males spend most time in mixed-sex
groups (Newton-Fisher, 1999). The community comes together for sleeping,
and participates in nest-building each night (Williams, et. al., 2002).
Males spend more time in parties than females do (Newton-Fisher, 1999). Females spend most of their time alone foraging in distinct but overlapping home ranges, but are sometimes involved in parties, especially when in estrous. However, males are more social, and spend most of their time in male parties or with sexually receptive females (Williams, et. al., 2002). More cycling females lead to a larger party size. Males appear to be in parties for relationship formation, especially for political reasons, and may invest a lot into these associations. The associations are non-random and tactical. Some chimps use “intense” strategy to build coalitions, others use it to receive benefits like meat and grooming (Newton-Fisher, 1999).
Boundaries of the Territory
Williams, et. al., (2002) convey that males patrol the boundaries and contest
unfamiliar individuals. Males cooperate for defense, and therefore stay in
their natal territories, while females are forced to emigrate. There is no
female-female aggression, except with newcomers to the community. Females
are evenly distributed across the habitat, minimizing female competition.
Males, however, are very competitive for mating, and coercion of females
becomes worse at the periphery. Male aggression in the boundaries forces
females to be members of one group exclusively. Most females show high site
fidelity and only a few emigrated once established in the community.