Association among wild orang-utans: sociality, passive aggregations or chance?

摘要: Encounters and associations between adult male, female subadult male orang-utans, Pongo pygmaeus, were examined at the Kutai National Park Gunung Palung Nature Reserve, Indonesia. Observed rates of encounters, durations proportions time spent in two members each age-sex class from population compared with expected values generated null models associations. Encounter rates, greater than by chance. Two factors appear to generate these non-random patterns: subjects both sites met conspecifics food sources more often expected, frequently involved social behaviour. Three differences association patterns existed populations. Orang-utans encountered other frequently, engaged longer associations, a proportion together Palung. Variations populations reflected In contrast males Kutai, avoided conspecific. Similarly, females less others did their counterparts. An analysis nature revealed additional behavioural Mating not occur Palung, but was observed received aggression, while those not. These data support hypothesis that variations reproductive states account for orang-utans. Sociality among orang-utans appears primarily result aggregation common resources, either or mates.