The socioecology of fission-fusion sociality in Orangutans

摘要: Fission-fusion systems can have the group or individual as their primary unit. In group-based fission-fusion systems, predation risk reduction is major benefit to grouping, in individual-based ones benefits are likely be primarily social. Orangutans, like chimpanzees, examples of an species. The orangutans inhabiting a Sumatran swamp forest (Suaq Balimbing) more than elsewhere form travel parties. As elsewhere, main grouping social: mating opportunities, protection from harassment and socialization infants. Most animals also incur costs, but these relatively low at Suaq Balimbing due high productivity swamp. Costs seem disproportionately for females with mid-sized infants, who avoid