Bonobo personality:Age and sex effects and links with behavior and dominance

Abstract The study described in this chapter examines whether individual differences in six rating-based bonobo personality dimensions—assertiveness, conscientiousness, openness, attentiveness, agreeableness and extroversion—are related to sex, age, behaviours and dominance. To these ends, the study tested predictions based on previous studies of human and chimpanzee personality, and bonobo behaviour and socio-ecology. Sex and age differences in assertiveness, openness and extroversion, and correlations between these personality dimensions and behaviour were consistent with predictions. Conscientiousness showed associations with observed behaviours but requires further investigation as sex and age effects differed from those reported in humans and chimpanzees. Agreeableness and attentiveness showed few associations with age, sex and behaviours, indicating the need to further investigate validity of these factors. This chapter shows that personality dimensions in bonobos are correlated with sex, age and behaviours in ways that are consistent with what is known for bonobos and their socio-ecology. L’étude décrite dans ce chapitre examine si les différences individuelles dans six dimensions de personnalité bonobos basées sur évaluation—Affirmation de soi, Conscience, Ouverture, Attention, Agréabilité, et l’Extroversion—sont liées au sexe et l’âge et les comportements et la dominance. L’étude a testé les prédictions basées sur des études précédentes de la personnalité humaine et chimpanzé, et le comportement bonobo et la socioécologie. Les différences de sexe et d’âge dans l’Affirmation de soi, l’Ouverture et l’Extroversion et les corrélations entre ces dimensions de personnalité et de comportement étaient cohérents avec nos prédictions. La Conscience montre des associations avec les comportements observés mais a besoin plus de recherche vu que les effets du sexe et de l’âge diffèrent des effets rapportés chez les humains et les chimpanzés. L’Agréabilité et l’Attention n’avaient pas autant d’associations avec l’âge, le sexe et les comportements. Cela montre qu’il faut plus rechercher la validité de ces facteurs. Cette étude montre que les dimensions de personnalité chez les bonobos sont corrélé à l’âge, au sexe et aux comportements de manières qui sont cohérentes avec notre connaissance des bonobos et de leur socioécologie.</jats:p

Adult bonobos show no prosociality in both prosocial choice task and group service paradigm

Previous studies reported contrasting conclusions concerning bonobo prosociality, which are likely due to differences in the experimental design, the social dynamics among subjects and characteristics of the subjects themselves. Two hypotheses have been proposed to explain the occurrence of prosociality in animals: the cooperative breeding hypothesis and the self-domestication hypothesis. While the former predicts low levels of prosociality in bonobos because they are non-cooperative breeders, the latter predicts high levels of prosociality because self-domestication has been proposed to select for high levels of tolerance in this species. Here, we presented a group of thirteen bonobos with two platform food-provisioning tasks: the prosocial choice task (PCT) and the group service paradigm (GSP). The latter has so far never been applied to bonobos. To allow for free choice of participation and partner, we implemented both tasks in a group setting. Like in previous PCT studies, bonobos did not choose the prosocial option more often when a group member could benefit vs not benefit. In the GSP, where food provisioning is costly, only subadult bonobos showed a limited amount of food provisioning, which was much lower than what was previously reported for chimpanzees. In both experiments, adult subjects were highly motivated to obtain rewards for themselves, suggesting that bonobos behaved indifferently to the gains of group members. We suggest that previous positive food-provisioning prosociality results in bonobos are mainly driven by the behaviour of subadult subjects. The lack of prosociality in this study corresponds to the hypothesis that proactive food provisioning co-occurs with cooperative breeding and suggests that proactive prosociality might not be part of the self-domestication syndrome in bonobos

Drivers of Dyadic Cofeeding Tolerance in Pan: A Composite Measure Approach

This study aimed to construct a composite model of Dyadic Cofeeding Tolerance (DCT) in zoo-housed bonobos and chimpanzees using a validated experimental cofeeding paradigm and to investigate whether components resulting from this model differ between the two species or vary with factors such as sex, age, kinship and social bond strength. Using dimension reduction analysis on five behavioral variables from the experimental paradigm (proximity, aggression, food transfers, negative food behavior, participation), we found a two-factor model: "Tolerant Cofeeding" and "Agonistic Cofeeding". To investigate the role of social bond quality on DCT components alongside species effects, we constructed and validated a novel relationship quality model for bonobos and chimpanzees combined, resulting in two factors: Relationship Value and Incompatibility. Interestingly, bonobos and chimpanzees did not differ in DCT scores, and sex and kinship effects were identical in both species but biased by avoidance of the resource zone by male-male dyads in bonobos. Social bonds impacted DCT similarly in both species, as dyads with high Relationship Value showed more Tolerant Cofeeding, while dyads with higher Relationship Incompatibility showed more Agonistic Cofeeding. We showed that composite DCT models can be constructed that take into account both negative and positive cofeeding behavior. The resulting DCT scores were predicted by sex, kinship and social bonds in a similar fashion in both Pan species, likely reflecting their adaptability to changing socio-ecological environments. This novel operational measure to quantify cofeeding tolerance can now be applied to a wider range of species in captivity and the wild to see how variation in local socio-ecological circumstances influences fitness interdependence and cofeeding tolerance at the dyadic and group levels. This can ultimately lead to a better understanding of how local environments have shaped the evolution of tolerance in humans and other species

Respiratory disease risk of zoo-housed bonobos is associated with sex and betweenness centrality in the proximity network

SIMPLE SUMMARY: One of the basic conditions of animal welfare is good health. While social behaviors have many benefits for group-living animals, they also play a role in disease transmission. This is especially true in primate species, like bonobos, who have complex social dynamics, which can facilitate disease transmission. Bonobos are also more susceptible to human disease variants due to their close genetic relatedness and are therefore at higher risk of infection in captivity due to closer proximity to humans. Therefore, investigation whether an individual’s characteristics, like sex, age, or social-network position increase disease risk provides information that can be used for future management decisions to improve general animal welfare. To do so, we monitored the occurrence of respiratory disease symptoms during one winter season in a relatively large group of 20 zoo-housed bonobos. We found that individuals that were more central in the social network had higher chances of contracting respiratory disease and that males were more likely to get infected than females. These results indicate that for bonobos, social behavior and sex influence the risk of contracting respiratory disease, two factors that can be taken into account when managing fission-fusion dynamics during disease outbreaks in this zoo-housed species. ABSTRACT: Infectious diseases can be considered a threat to animal welfare and are commonly spread through both direct and indirect social interactions with conspecifics. This is especially true for species with complex social lives, like primates. While several studies have investigated the impact of sociality on disease risk in primates, only a handful have focused on respiratory disease, despite it being a major cause of morbidity and mortality in both wild and captive populations and thus an important threat to primate welfare. Therefore, we examined the role of social-network position on the occurrence of respiratory disease symptoms during one winter season in a relatively large group of 20 zoo-housed bonobos with managed fission-fusion dynamics. We found that within the proximity network, symptoms were more likely to occur in individuals with higher betweenness centrality, which are individuals that form bridges between different parts of the network. Symptoms were also more likely to occur in males than in females, independent of their social-network position. Taken together, these results highlight a combined role of close proximity and sex in increased risk of attracting respiratory disease, two factors that can be taken into account for further welfare management of the species

Bonobo personality predicts friendship

In bonobos, strong bonds have been documented between unrelated females and between mothers and their adult sons, which can have important fitness benefits. Often age, sex or kinship similarity have been used to explain social bond strength variation. Recent studies in other species also stress the importance of personality, but this relationship remains to be investigated in bonobos. We used behavioral observations on 39 adult and adolescent bonobos housed in 5 European zoos to study the role of personality similarity in dyadic relationship quality. Dimension reduction analyses on individual and dyadic behavioral scores revealed multidimensional personality (Sociability, Openness, Boldness, Activity) and relationship quality components (value, compatibility). We show that, aside from relatedness and sex combination of the dyad, relationship quality is also associated with personality similarity of both partners. While similarity in Sociability resulted in higher relationship values, lower relationship compatibility was found between bonobos with similar Activity scores. The results of this study expand our understanding of the mechanisms underlying social bond formation in anthropoid apes. In addition, we suggest that future studies in closely related species like chimpanzees should implement identical methods for assessing bond strength to shed further light on the evolution of this phenomenon