The human ego has never been quite the same since the day in that Jane Goodall observed a chimpanzee feasting on termites near Lake Tanganyika. After carefully trimming a blade of grass, the chimpanzee poked it into a passage in the termite mound to extract his meal. No longer could humans claim to be the only tool-making species.
Female chimpanzees exhibit exceptionally slow rates of reproduction and raise their offspring without direct paternal care. Therefore, their reproductive success depends critically on long-term access to high-quality food resources over a long lifespan. Chimpanzee communities contain multiple adult males, multiple adult females and their offspring. Because males are philopatric and jointly defend the community range while most females transfer to new communities before breeding, adult females are typically surrounded by unrelated competitors. Communities are fission—fusion societies in which individuals spend time alone or in fluid subgroups, whose size depends mostly on the abundance and distribution of food. To varying extents in different populations, females avoid direct competition by foraging alone or in small groups in distinct, but overlapping core areas within the community range to which they show high fidelity. Although rates of aggression are low, females compete for space and access to food. High rank correlates with high reproductive success, and high-ranking females win direct contests for food and gain preferential access to resource-rich sites. Females are aggressive to immigrant females and even kill the newborn infants of community members.
By Ewen Callaway. Yet unlike chimps , bonobos live in female-centred societies where sex, not aggression, settles differences and enforces social order. Small ungulates called forest antelopes, or duikers, often fall prey to the apes.
Carson M. Murray, Elizabeth V. Lonsdorf, Lynn E. Eberly, Anne E. Mammalian females generally carry the bulk of reproductive costs. They gestate for relatively long periods of time and provide the majority of parental care for dependent offspring. For this reason, many studies have examined how females deal with the energetic costs of reproduction. Here, we examine the influence of reproductive state on activity budgets, diet quality, and sociality in free-living female chimpanzees Pan troglodytes at Gombe National Park, Tanzania. After controlling for dominance rank, we found that pregnant and lactating females consumed higher quality foods than nonpregnant, nonlactating females. However, pregnant females also traveled less.