Social structures in Pan paniscus: testing the female bonding hypothesis

Abstract

Based on previous research in captivity, bonobos, Pan paniscus, have been called a female-bonded species. However, genetic and behavioural data indicate that wild females migrate. Bonding between these unrelated females would then be in contradiction with socio-ecological models. It has been argued that female bonding has been overemphasized in captive bonobos. We examine patterns of proximity, grooming and support behaviour in six well established captive groups of bonobos. We find that female bonding was not a typical characteristic of all captive bonobo groups. In only two groups there was a trend for females to prefer proximity with other females over association with males. We found no evidence that following or grooming between females was more frequent than between males and unrelated females or between males. Only in coalitions, females supported each other more than male-female or male-male dyads. We also investigated five mother-son pairs. Grooming was more frequent among mothers and sons than in any other dyad, but sons did not groom their mothers more than males groomed unrelated females. Mothers groomed their sons, or provided more support to them than females groomed or supported unrelated males. Thus, while bonds between females were clearly present, intersexual relations between males and either unrelated females or their mothers are of more, or equal importance.

Multi-Modal Use of a Socially Directed Call in Bonobos

“…ZC collected data on aggression at the time of this study, with fleeing from aggression as a marker for dominance, as demonstrated by previous studies of bonobo social behaviour e.g., [62]. To calculate dominance relationships, we used the Matman analysis programme (Noldus, version 1.1; Wageningen, The Netherlands).…”

“…To calculate dominance relationships, we used the Matman analysis programme (Noldus, version 1.1; Wageningen, The Netherlands). Following earlier studies, e.g., [62], [63], we investigated whether the dominance hierarchy was linear by calculating the adjusted linearity index h', which takes into account the number of unknown relationships [63], [64].…”

Communication during sex among female bonobos: effects of dominance, solicitation and audience

“…In order to assess the effect of social dominance on copulation calls, we focussed on the outcome of dyadic agonistic interactions33, by using ‘fleeing upon aggression’ as a behavioural marker for dominance2044. Dominance relationships and linearity were calculated using Matman (Noldus, version 1.1) in each study group.…”

“…We then calculated the adjusted linearity index (h'), corrected for the number of unknown relationships and the direction consistency index (see supplementary information). For significantly linear hierarchies, we calculated individual cardinal rank scores using normalised David's Scores, corrected for chance44. Using regression plots of these scores, we divided females into either high or low rank clusters, based on their position in the hierarchies (fig.…”

A Case Study of Conflict Management in Bonobos: How Does a Bonobo (Pan paniscus) Mother Manage Conflicts between Her Sons and Her Female Coalition Partner?

“…Coalitions between female relatives are often impossible due to female transfers [Kano, 1987;Furuichi, 1989] between groups but, in spite of this limitation, groups are structured around supportive relationships between unrelated adult females [Badrian and Badrian, 1984;White, 1988;Kano, 1992;Furuichi and Ihobe, 1994;Parish, 1994Parish, , 1996de Waal, 1995;Furuichi, 1997;Parish and de Waal, 2000;Vervaecke et al, 2000b, c;Stevens et al, 2006]. These coalitions provide their members with a series of advantages, such as a preferential access to food resources and the possibility for females to give birth at younger ages, which result in increased reproductive success [Parish, 1996;Hohmann et al, 1999].…”