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Patterns of coalitionary aggression among female animals are generally explained by kin selection theory. Frequent female coalitions are almost exclusively observed in female-philopatric species, where females stay in their natal group, and females typically form coalitions with their kin. Bonobos, Pan paniscus, in contrast, are male-philopatric, w...
Contexts in source publication
Context 1
... individuals were identified and habituated from the beginning of the study period. Our study subjects were individuals who were more than 8 years old, but we excluded one female who emigrated during the study period (15 individuals: nine females and six males, Table 1). Data on females who temporarily visited this group were not analysed. ...
Context 2
... support may be due to unidirectional relationships within a dyad in which older females support younger ones. Old Bk 0 2 0 1 4 1 0 0 Old Kb 0 0 1 2 6 0 1 0 Old Hd 1 0 1 2 2 7 3 0 Middle Mt 0 0 0 0 1 0 1 1 Middle Po 0 0 0 1 3 5 0 1 Middle Ic 0 Figure 4. Females' winning rate against males in each age category. White bar: win- ning rate of females in dyadic aggressive interactions; grey bar: winning rate of fe- males when they formed a coalition. ...
Citations
... Adult male gorillas, however, are competitive with each other (Robbins, 1996), and those who are co-resident typically avoid one another (Robbins, 1996;Stoinski et al., 2009). Females are often considered to exhibit relatively weak relationships with each other compared to those between males and females (Harcourt, 1979b;Watts, 1994bWatts, , 2002a or those exhibited by other African apes (Bray & Gilby, 2020;Mitani, 2009;Tokuyama & Furuichi, 2016;Wrangham, 1980). This apparent weakness may be due to their diet and dispersal patterns. ...
Strong, affiliative relationships are important across social mammals, and in many species, relationships between female kin form the basis of group life. Relationships are expected to be weaker in cases where females disperse or do not cooperatively defend resources. Mountain gorillas, Gorilla beringei beringei, seem to support this, as females can emigrate multiple times throughout their life and do not jointly defend the abundant vegetation they feed on. Unsurprisingly, mountain gorillas have been reported to form variable or weak relationships with other females and seemingly prioritize relationships with adult males. But prior studies may have misinterpreted relationships due to a focus on grooming and understandable limitations of small sample sizes and short study periods. Here, we examine proximity and grooming between 47 adult female mountain gorillas in five groups over 5e13 years. We analyse proximity data (2 m, 5 m) and grooming relationships between 366 individual dyads to determine (1) whether proximity and grooming relationships are preferential and (2) whether they endure across time. Most females formed at least one preferential 2 m and 5 m proximity relationship (43 of 47), which both lasted a mean of 2.1 years. Additionally, 3.6% of dyads (N = 13/366) formed enduring 2 m proximity preferences that exceeded 4 years, with the longest lasting at least 12 years. Maternal kin had the most enduring proximity and grooming relationships, although grooming was rare overall. The enduring proximity relationships between some female gorillas in our sample are similar in length to those of female yellow baboons, Papio cynocephalus, and male chimpanzees, Pan troglodytes, which are considered social bonds. Mountain gorillas provide a system in which factors influencing bonds can be better understood, and our study highlights a need to refine definitions of social bonds while potentially reassessing their evolutionary function.
... Bonobos are a fascinating subject to study social relationship between females in that female-female support is important for females to overcome male aggression toward them and the mother-son bond plays an important role in mating success and dominance rank acquisition of males (Surbeck et al. 2011;Furuichi 2011;Tokuyama and Furuichi 2016). How could bonobos have achieved such a femalecentered society (Furuichi 2011) where females play important social roles that even directly influence the dominance hierarchy between males? ...
... Therefore, most adult female bonobos in a group are not genetically related to one another (Hohmann et al. 1999;Ishizuka et al. 2018). These unrelated females support each other in agonistic interactions with males (Parish 1996; Tokuyama and Furuichi 2016). The coalitionary support between females against males seems not to be directly associated with female-female grooming, proximity patterns, or GGR (Tokuyama and Furuichi 2016;Moscovice et al. 2017). ...
... These unrelated females support each other in agonistic interactions with males (Parish 1996; Tokuyama and Furuichi 2016). The coalitionary support between females against males seems not to be directly associated with female-female grooming, proximity patterns, or GGR (Tokuyama and Furuichi 2016;Moscovice et al. 2017). This is different from what has been reported for male chimpanzees where the formation of grooming networks corresponds well with their coalition networks (Watts 2000b). ...
Feeding competition and predation risk are two important factors determining female reproductive success and interfemale relationships (Sterck et al. 1997). Although an increase in the number of individuals in a group can reduce the predation risk for each individual, it also increases competition over food. As feeding competition directly influences female reproductive success, there may be an optimal number of females in a group depending on the social and ecological situation (Markham et al. 2015). When the number of females in a group increase, competition between females over food will also increase. Such competition over food will result in a species-specific social structure that results from struggling of females to acquire a better social position (Barton et al. 1996; Kappeler and van Schaik 2002; Pusey and Schroepfer-Walker 2013). After an establishment of social structure, the social structure will then stabilize how local resources are distributed to females and influence fitness of each female. For example, increased contest competition over food may result in a more linear hierarchy that may reduce one’s fitness in a lower hierarchy as it will reduce the chance of access to food to them (Sterck et al. 1997). In such a group, group females may not be able to utilize the maximum local carrying capacity as resources will be distributed unequally and may result in surplus and scarcity for individuals in different hierarchies. On the other hand, if females are tolerating each other, so the social structure does not hinder resource allocation between females of different social ranks, this tolerant social structure may help females even in a lower social rank utilize the local resource better (Hamilton et al. 2009).
... Although females within groups are typically immigrants and assumed to be nonkin with each other due to female dispersal, female bonobos are very social and play an important role in creating the peaceful nature of their society (Furuichi 2011). They often show af liative and cooperative interactions with each other (Parish 1996;Tokuyama and Furuichi 2016;Moscovice et al. 2017). In contrast to females, male bonobos are typically unsocial. ...
... In contrast to females, male bonobos are typically unsocial. Compared to chimpanzees (Pan troglodytes), the closest evolutionary neighbors of bonobos, the intensity of male aggression is moderate (Ihobe and Furuichi 1994;Stanford 1998;Wilson et al. 2014;Surbeck and Hohmann 2017), and cooperation among males is seldom observed (Surbeck and Hohmann 2013;Tokuyama and Furuichi 2016;Surbeck et al. 2017a). Furthermore, although intergroup relationships are typically antagonistic in primates, those of bonobos are highly tolerant and even peaceful. ...
Bonobos (Pan paniscus) are one of the closest evolutionary neighbors to humans. They live in societies that contain various rare traits among animal species. Unlike most primates that form female-philopatric groups (Wrangham 1980; Lawson-Handley and Perrin 2007), bonobos form male-philoparic groups, in which males remain in their natal groups and females disperse after sexual maturity (Kano 1992; Hashimoto et al. 2008; Sakamaki et al. 2015). Although females within groups are typically immigrants and assumed to be nonkin with each other due to female dispersal, female bonobos are very social and play an important role in creating the peaceful nature of their society (Furuichi 2011). They often show affinitive and cooperative interactions with each other (Parish 1996; Tokuyama and Furuichi 2016; Moscovice et al. 2017). In contrast to females, male bonobos are typically unsocial. Compared to chimpanzees (Pan troglodytes), the closest evolutionary neighbors of bonobos, the intensity of male aggression is moderate (Ihobe and Furuichi 1994; Stanford 1998; Wilson et al. 2014; Surbeck and Hohmann 2017), and cooperation among males is seldom observed (Surbeck and Hohmann 2013; Tokuyama and Furuichi 2016; Surbeck et al. 2017a). Furthermore, although intergroup relationships are typically antagonistic in primates, those of bonobos are highly tolerant and even peaceful. When neighboring bonobo groups encounter each other, they often merge peacefully, and affinitive interactions and copulations among individuals from different groups are often observed (Idani 1990; Hohmann and Fruth 2002; Lucchesi et al. 2020; Tokuyama et al. 2020). It remains unclear why such unique characteristics have evolved in our closest living relatives. Clarifying the factors facilitating the evolution of such unique characteristics in bonobo societies could contribute to understanding how dynamic and flexible cooperation has evolved in humans.
... Females form coalitions as well, though more frequently among bonobos, as female chimpanzees are less gregarious by comparison (Mitani, 2009). Despite not being directly related, female bonobos readily form coalitions with other females, usually to attack males that have been aggressive to someone in the coalition (Tokuyama & Furuichi, 2016), which may theoretically prevent the rise of despotic male bonobos (Ronay, Maddux & von Hippel, 2020). Male bonobos form coalitions in the context of within-group conflict as well, though they form most coalitions with females (Surbeck et al., 2017). ...
This article discusses dominance personality dimensions found in primates, particularly in the great apes, and how they compare to dominance in humans. Dominance traits are seen in virtually all primate species, and these dimensions reflect how adept an individual is at ascending within a social hierarchy. Among great apes, dominance is one of the most prominent personality factors but, in humans, dominance is usually modeled as a facet of extraversion. Social, cultural, and cognitive differences between humans and our closest ape relatives are explored, alongside humanity’s hierarchical and egalitarian heritage. The basic characteristics of dominance in humans and nonhuman great apes are then described, alongside the similarities and differences between great apes. African apes live in societies each with its own hierarchical organization. Humans were a possible exception for some of our history, but more recently, hierarchies have dominated. The general characteristics of high-dominance humans, particularly those living in industrialized nations, are described. Dominance itself can be subdivided into correlated subfactors: domineering, prestige, and leadership. Various explanations have been posed for why dominance has declined in prominence within human personality factor structures, and several possibilities are evaluated. The value of dominance in personality research is discussed: dominance has links to, for instance, age, sex, aggression, self-esteem, locus of control, stress, health, and multiple socioeconomic status indicators. The piece concludes with recommendations for researchers who wish to assess dominance in personality.
... In chimpanzees, collective territorial boundary patrolling, which can expose participants to lethal aggression, is facilitated by strong, enduring, dependable dyadic social bonds, which also underlie dyadic coalitions and alliances in chimpanzee during within-group competition (Bray et al., 2021;Mitani, 2009;Mitani et al., 2000;Nishida, 1983;Samuni et al., 2021;Samuni, Mielke, et al., 2020). By contrast, in bonobos, collective territorial boundary patrolling and lethal aggression do not occur, and both affiliative and cooperative interactions show less dyadic predictability (Moscovice et al., 2017(Moscovice et al., , 2019Surbeck, Girard-Buttoz, et al., 2017;Tokuyama & Furuichi, 2016). It is possible that the emotions that underlie dyadic bonds in chimpanzees may trigger interventions in conflicts where bond partners, including dependent offspring, are harmed (Sandel & Watts, 2021). ...
... Female-preferential coalitions have been observed in primates, as in the case of wild female bonobos (Pan paniscus) or rhesus macaques (Macaca mulatta) [52,91]. In this study, sex of the interferer was not a significant predictor of most of the studied variables. ...
Background
Third-party interference in agonistic contests entails a deliberate intervention in an ongoing fight by a bystanding individual (third party) and may be followed by post-conflict social behaviour to provide support to a specific individual. The mechanisms behind third-party intervention are, however, still largely understudied. The aim of this study was to investigate third-party interference, with the predictions that (1) the interferer derives benefits from its action by winning a fight, (2) that patterns of intervention depend on familiarity, (3) that dyadic fights last longer than triadic fights, and (4) that interferers engage in non-agonistic social behaviours afterwards. Pre-pubertal pigs (Sus scrofa) (n = 384) were grouped with one familiar and four unfamiliar conspecifics (all non-kin) to elicit contests for dominance rank. Third-party interference was analysed for the first 30 min after grouping, along with the behaviour (nosing or aggression), contest duration, contest outcome, and interferer behaviour after the fight (post-conflict social behaviour).
Results
Three types of interference were observed: non-agonistic involvement (nose contact) by the interferer in a dyadic fight; a triadic fight with each of three contestants fighting one opponent at a time; and triadic fights with two opponents jointly attacking the third one (two-against-one fights). The likelihood of a third-party intervention to occur did not depend on the presence of a familiar animal in the fight. However, once intervention was triggered, interferers attacked unfamiliar fight initiators more than familiar ones. Two-against-one fights lasted longer than other triadic fights and occurred more often when both initial contestants were females. Results of 110 triadic fights (out of 585 fights in total) revealed that interferers were more likely to win compared to the initial opponents at equal body weight. The most common post-conflict behaviour displayed by the interferer was agonistic behaviour towards another group member, independently of familiarity.
Conclusions
The general lack of discrimination for familiarity suggests interference is not driven by support to familiar individuals in pigs. The results show that intervening in an ongoing fight gives the interferer a high chance of contest success and may be a strategy that is beneficial to the interferer to increase its dominance status.
... Helping others promotes the selfconstruction of positive psychological qualities in adolescents (61). In addition, it manifests individual integration and harmony with the collective (62) and is regarded as an important way of constructing interpersonal alliances and cooperation (63), and self-construction of healthy psychological qualities from the perspectives of interpersonal relationships and social adaptation. The construction of these positive psychological qualities has significance for the self-healing of depression. ...
Purpose
This study aims to explore the mechanism of psychological qualities constructed in helping others with depression and guide adolescents to actively participate in the practical activities of helping others to prevent and self-heal depression.
Method
Symptom self-rating scale, trait coping style questionnaire, and self-administered helper scale were employed. A total of 1,086 valid on-site questionnaires were collected from adolescents.
Result
The depression levels of adolescents were negatively correlated with helping beliefs, behaviors and total scores (r = −0.500, −0.401, and −0.530). Helping others had a significantly negative predictive effect on depression, effectively inhibiting depression levels. Although the positive coping style had an inhibitory effect on depression, it exerted no predictive effects on depression under the influence of helping others. In contrast, the negative coping style had a significantly positive predictive effect on depression.
Conclusion
Proactively participating in helping others is an important way to prevent and eliminate depression in adolescents. They should be instructed to give full play to their initiatives to participate in social practice and assist others actively, thus constructing positive psychological qualities, improving mental health, and achieving self-healing of depression and self-help through helping others.
... Research in female Japanese macaques, gorillas and langurs have disputed the link between SSB and coalitionary behaviour 1,31,50 . In female bonobos (for which there is strong evidence of a reconciliatory function via post-conflict SSB between opponents 24,25 ), the coalitionary support function remains popular 25 but somewhat unresolved 1,[51][52][53][54] . Initial reports of a function 103,104 were later questioned 1,51-53 , although a more recent study did find evidence of coalitionary support to sociosexual interactions, but only when female-male sociosexual behaviours were included with femalefemale behaviours in the dataset 54 . ...
Numerous reports have documented the occurrence of same-sex sociosexual behaviour (SSB) across animal species. However, the distribution of the behaviour within a species needs to be studied to test hypotheses describing its evolution and maintenance, in particular whether the behaviour is heritable and can therefore evolve by natural selection. Here we collected detailed observations across 3 yr of social and mounting behaviour of 236 male semi-wild rhesus macaques, which we combined with a pedigree dating back to 1938, to show that SSB is both repeatable (19.35%) and heritable (6.4%). Demographic factors (age and group structure) explained SSB variation only marginally. Furthermore, we found a positive genetic correlation between same-sex mounter and mountee activities, indicating a common basis to different forms of SSB. Finally, we found no evidence of fitness costs to SSB, but show instead that the behaviour mediated coalitionary partnerships that have been linked to improved reproductive success. Together, our results demonstrate that SSB is frequent in rhesus macaques, can evolve, and is not costly, indicating that SSB may be a common feature of primate reproductive ecology.
... In some species, females may cooperate with kin to combat male aggression and harassment (rhesus macaques: [134,135]; olive baboons: [136]; also review by Smuts [137]). Strikingly, in bonobos, females form coalitions with unrelated females; this strategy may have evolved to counter sexual coercion and/or infanticide by males [52,138,139]. One of the key behaviours facilitating female social bonding in bonobos is genito-genital rubbing, which often involves maximally tumescent females [140,141]. ...
... Male reproductive skew depends not just on competition among males, but also on relationships between males and females, and female choice. Studies of other species have found that males can gain mating opportunities by forming close associations with females [181,196,197] and by caring for offspring [181,[196][197][198][199]. Female bonobos probably have more agency in the expression of mate choice owing to their high status [52,139] and strong female alliances [52,138,139]. Because female bonobos tend to affiliate and mate with high-ranking rather than low-ranking males, female preferences probably contribute to higher skew in bonobos than chimpanzees. ...
Reproductive inequality, or reproductive skew, drives natural selection, but has been difficult to assess, particularly for males in species with promiscuous mating and slow life histories, such as bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Although bonobos are often portrayed as more egalitarian than chimpanzees, genetic studies have found high male reproductive skew in bonobos. Here, we discuss mechanisms likely to affect male reproductive skew in Pan, then re-examine skew patterns using paternity data from published work and new data from the Kokolopori Bonobo Reserve, Democratic Republic of Congo and Gombe National Park, Tanzania. Using the multinomial index (M), we found considerable overlap in skew between the species, but the highest skew occurred among bonobos. Additionally, for two of three bonobo communities, but no chimpanzee communities, the highest ranking male had greater siring success than predicted by priority-of-access. Thus, an expanded dataset covering a broader demographic range confirms that bonobos have high male reproductive skew. Detailed comparison of data from Pan highlights that reproductive skew models should consider male–male dynamics including the effect of between-group competition on incentives for reproductive concessions, but also female grouping patterns and factors related to male–female dynamics including the expression of female choice.
This article is part of the theme issue ‘Evolutionary ecology of inequality’.
... Chimpanzees exhibit strong and enduring male-male bonds; bonobos exhibit co-operative female-female relationships imbued with frequent sexual behavior. 60,98 It is possible that both bonds represent homologous underlying mechanisms. Comparable relationships are not found in other hominoids: gorillas exhibit relatively weak bonds and orangutans do not exhibit bonds outside the mother-offspring pair. ...
The evolution of monogamy has been a central question in biological anthropology. An important avenue of research has been comparisons across "socially monogamous" mammals, but such comparisons are inappropriate for understanding human behavior because humans are not "pair living" and are only sometimes "monogamous." It is the "pair bond" between reproductive partners that is characteristic of humans and has been considered unique to our lineage. I argue that pair bonds have been overlooked in one of our closest living relatives, chimpanzees. These pair bonds are not between mates but between male "friends" who exhibit enduring and emotional social bonds. The presence of such bonds in male-male chimpanzees raises the possibility that pair bonds emerged earlier in our evolutionary history. I suggest pair bonds first arose as "friendships" and only later, in the human lineage, were present between mates. The mechanisms for these bonds were co-opted for male-female bonds in humans.
