Postconflict Behavior of Spectacled Leaf Monkeys (Trachypithecus obscurus). I. Reconciliation

Studies of postconflict behavior have focused on Old World primates, particularly on members of the cercopithecines and chimpanzees. We present data on patterns of reconciliation in two captive groups of spectacled leaf monkeys, members of the Colobinae. Reconciliation occurred at a high rate relative to that in other primate species and within the first minute following a conflict. Friendly postconflict contact was usually initiated by aggressors in one group, and by recipients in the other. But, there was no difference in postconflict initiative to contact in comparison with MCs. These two groups showed behavioral specificity in the context of postconflict reunions. Ventroventral embracing was a common, explicit (de Waal, 1993) form of reconciliation. The intensity of aggression and situations in which the victim responded aggressively had no effect on the likelihood of reconciliation occurring. The postconflict behavior of both groups lends further support to the relationship-quality hypothesis (Aureli et al., 1989). Kinship and rank distance and had no effect on reconciliation, though affiliation levels correlated positively with the tendency to reconcile. These results indicate that spectacled langurs are among the more tolerant of the species studied so far.     

Postconflict third-party affiliation in rooks, Corvus frugilegus

Conflict features in the lives of many animal species and induces social stress mediated by glucocorticoid hormones [1]. Postconflict affiliation, between former opponents (reconciliation) or between former opponents and a bystander (third-party affiliation), has been suggested as a behavioral mechanism for reducing such stress [2], but has been studied almost exclusively in primates [3]. As with many primates, several bird species live in social groups and form affiliative relationships [4]. Do these distantly related animals also use affiliative behavior to offset the costs of conflict? We studied postconflict affiliation in a captive group of rooks. Unlike polygamous primates, monogamous rooks did not reconcile with former opponents. However, we found clear evidence of third-party affiliation after conflicts. Both initiators and targets of aggression engaged in third-party affiliation with a social partner and employed a specific behavior, bill twining, during the postconflict period. Both former aggressors and uninvolved third parties initiated affiliative contacts. Despite the long history of evolutionary divergence, the pattern of third-party affiliation in rooks is strikingly similar to that observed in tolerant primate species. Furthermore, the absence of reconciliation in rooks makes sense in light of the species differences in social systems.     

Affiliation Between Aggressors and Third Parties Following Conflicts in Long-Tailed Macaques (Macaca fascicularis)

Studies on cercopithecine monkeys have shown that soon after an agonistic conflict, victims have increased rates of affiliation with the agressor—reconciliation—but not with other group members. Postconflict affiliation is thought to function to restore disturbed relationships and to reduce social tension. This study on a captive group of long-tailed macaques (Macaca fascicularis) is focused on postconflict affiliative behavior of the aggressor. Increased rates of contact between female aggressors and kin of the victim occurred, as well as between female aggressors and their own kin. Furthermore, there were increased rates of contact between aggressors—males and females—and other group members. The increase in contacts with the victim's kin was selective, i.e., it could not be ascribed to the increased contact tendency with group members in general, and was not a side effect of the aggressor's proximity to the victim due to reconciliation. The increase in contacts with own kin was not selective. The fact that male aggressors do not have increased postconflict contacts with their kin or with kin of the victim is in agreement with the notion that males are less integrated in the nepotistic matrilineal network than females are. The fact that studies by others that focused on the victim evidence no increase in postconflict contacts with kin of the opponent or with other group members may be explained by the aggressor's larger influence over the postconflict situation: to reduce social tension, it might be more effective to affiliate with the aggressor than with the victim. Our findings emphasize that conflicts influence the behavior of other monkeys besides the direct contestants and, thus, indicate that the disturbance of social homeostasis is a matter of concern for all group members.     

Postconflict Behavior of Captive Brown Capuchins in the Presence and Absence of Attractive Food

Most of what we know about postconflict behavior comes from studies on chimpanzees and other Old World semiarboreal and semiterrestrial species. Few studies have investigated whether the context of a fight affects reconciliation—selective postconflict attraction between former opponents—and consolation: selective attraction between conflict participants and other group members. We studied social conflict and its aftermath in two captive groups of brown capuchins (Cebus apella), an arboreal New World species. We observed postconflict behavior in two contexts: (1) during the presence of highly attractive, clumped food—food condition—and (2) in the absence of such food—nonfood condition. Commercial monkey chow was available ad libitum in the nonfood condition. A comparison of postconflict and control observations revealed a conciliatory tendency in the capuchins, but only following fights that occurred in the absence of highly attractive food. Other group members tended not to seek postconflict contact with former conflict participants. However, when shortly after fights recipients of aggression, but not aggressors, initiated affiliation with third parties, the latter not only allowed proximity or contact but also often reciprocated through grooming, play, and especially the exchange of friendly signals. We discuss these results within the framework of current knowledge of postconflict behavior with special emphasis on similarities and differences in the postconflict behavior of Cebus and Pan.     

Reconciliation, consolation and postconflict behavioral specificity in chimpanzees

Conflicts of interest arise regularly in the lives of all group-living animals and may escalate into aggressive conflicts. The costs of aggressive escalation can be reduced through peaceful postconflict interactions. This study investigated the postconflict behavior of 22 adult chimpanzees at Chester Zoo. The occurrence of reconciliation, i.e. the postconflict affiliative reunion between conflict opponents, and consolation, i.e. a postconflict affiliative interaction directed from a third party to the recipient of aggression, were demonstrated. Consolation was more likely to occur in the absence of reconciliation than after reconciliation, and reconciliation was more likely to occur in the absence of consolation than after consolation, supporting the hypothesis that consolation acts as a substitute for reconciliation when the latter fails to occur. Evidence for behavioral specificity, i.e. context-specific use of certain behaviors, was found for both reconciliation and consolation, which, along with high conciliatory tendencies, suggests an explicit style of postconflict behavior in the study subjects.     

Postconflict Behavior Among Male Japanese Macaques

Reconciliation was first described more than 20 years ago. Since then, it has been observed in many mammals (mainly primates) but data on postconflict behavior among males are still scarce because they usually aggressively compete for mating partners, rarely maintain amicable relationships with one another. Accordingly, reconciliation is expected to occur at low rates. Although this is true for Japanese macaque males, the subspecies on Yakushima Island (Macaca fuscata yakui) seems to represent an exception as grooming among males occurs often. We analyzed postconflict behavior among them and discuss the possible factors that may favor the occurrence of grooming and reconciliation. Selective attraction between former opponents—reconciliation—occurred soon after conflicts. Consolation—affiliative interactions between a focal animal and group members other than the former opponents occurring earlier in PCs than in MCs—was absent among males. Conciliatory tendency is higher for Yakushima macaque males (0.31) versus that in studies on the other subspecies Macaca fuscata. We discuss differences in the behavioral ecology of the 2 subspecies, the ecological and social factors that may favor the occurrence of reconciliation, and the possible benefits that males gain from grooming exchange and reconciliation.     

Postconflict Affiliation of Aggressors in <Emphasis Type="Italic">Papio hamadryas</Emphasis>

Researchers have associated variation in the occurrence of postconflict behaviors with variation in the relationship quality between involved individuals. Apart from those on the great apes, the vast majority of postconflict studies involved female-bonded species and focused on the victim. We examined postconflict affiliation involving the aggressor in a non-female-bonded species, hamadryas baboons (Papio hamadryas), and investigated the influence of relationship quality on the occurrence of 2 types of postconflict affiliative behaviors. Hamadryas baboons reconciled after a conflict and the highest rate of reconciliation was between one-male unit (OMU) leader males and their females. Via direct measures of relationship characteristics we also found that partners with higher-quality relationship, e.g., highly affiliative dyads and allies, showed higher levels of conciliatory tendency than dyads with lower-quality relationship, e.g., less affiliative dyads and non-allies. We found evidence of postconflict third-party affiliation initiated by aggressors, but not by third parties. Further, aggressor-initiated affiliation was more likely with individuals of the same OMU and individuals with which the aggressor maintained a strongly affiliative relationship. Our findings provide further support for relationship quality as a fundamental underlying factor not only in reconciliation, but also in postconflict affiliations involving third parties.     

Postconflict affiliative contacts between former opponents among wild moor macaques (Macaca maurus)

Agonistic interactions and postconflict behavior of moor macaques (Macaca maurus) were studied in their natural habitat, South Sulawesi, Indonesia. Individuals were involved in 0.28 agonistic interactions per hour. Forty-two percent of agonistic interactions were followed by affiliative contacts between the former opponents. Such affiliative contacts occurred within 2 minutes of the agonistic interaction and were most often initiated by the victim's approach to the aggressor. The most common postconflict behavior was grooming of the aggressor by the victim. The present study provides further evidence of a positive correlation between a high tendency for postconflict affiliative contact and a relaxed dominance style. Captivity might not alter the expression of postconflict behavior. The present study suggests that it is possible to demonstrate the occurrence of reconciliation a posteriori by using data obtained by general focal observation protocols. © 1996 Wiley-Liss, Inc.     

Postconflict behavior among female Sichuan snub-nosed monkeys Rhinopithecus roxellana within one-male units in the Qinling Mountains, China

For group-living primates, the information on postconflict management is crucial for understanding primate competition and cooperation. However, such information is poorly known for snub-nosed monkeys, especially for wild populations. In this study, from September 2007 to June 2008, we investigated postconflict behavior among adult females Sichuan snub-nosed monkeys Rhinopithecus roxellana within one-male units in a wild, provisioned group in the Qinling Mountains of China by means of the time-rule method and the PC-MC method. We obtained a total of 81 PC-MC pairs and each individual was involved in only 0.004 aggressive behavior per observation hour. The first affiliative behavior was more likely to occur within the first minute after a conflict. The postconflict affiliative behaviors most often seen were contact-sit, embrace and grooming. The affiliative contacts between adult females occur due to selective attraction, I.e. Reconciliation. The pattern of postconflict affiliation demonstrates that the R. Roxellana belongs to a tolerant species.     

The Function and Determinants of Reconciliation in <Emphasis Type="BoldItalic">Pan troglodytes</Emphasis>

Reconciliation (the postconflict affiliative reunion between former opponents) may mitigate costs of aggressive conflict by repairing the opponents’ relationship and reducing stress. We showed that postconflict levels of self-directed behavior were lower after reconciliation than when reconciliation did not occur in chimpanzees (Pan troglodytes) at Chester Zoo, providing support for a stress-alleviating function for reconciliation. Further, we investigated the effects of multiple factors on the occurrence of reconciliation using generalized linear mixed models. We performed 2 separate analyses, a “traditional” analysis and a “targeted” analysis. The former included variables previously used to assess the occurrence of reconciliation in primates, i.e., conflict characteristics, sex combination, and a simple measure of relationship value. The latter included species-specific variables such as the occurrence of consolation (postconflict affiliation from a bystander to the recipient of aggression); initiation of the conflict with a bluff display; and measures of relationship value, compatibility, and security specific to the study group. Whereas the traditional analysis showed that female-female dyads and valuable partners were most likely to reconcile, the targeted analysis showed that reconciliation was less likely to occur when consolation took place or when aggression was initiated with bluff displays. Further analyses revealed that the effect of sex-combination on reconciliation was due to its intercorrelation with bluff display. This study highlights the importance of considering variables specific to the study species and group when investigating the determinants of reconciliation and warns against premature interpretation of results without due consideration for all other possible determinants.     

Reconciliation in three groups of lion-tailed macaques

We studied postconflict behavior in three captive groups of lion-tailed macaques (Macaca silenus). After a conflict, we monitored the aggressee as the focal individual during a 10-min postconflict period and made control observations the following day on the same individual. Selective attraction between former opponents occurred in the first minutes of the postconflict period. The conciliatory tendency was relatively high, about 40%. Although no specific behavior was used to reconcile, postconflict contacts were especially intense and a rich repertoire of affiliative patterns was exihibited. With regard to the rate and form of reconciliation, lion-tailed macaques resemble Sulawesi macaques, which belong to the same phyletic lineage. We also discuss the possible interrelations between conciliatory patterns and other characteristics of social organization.     

Postconflict Affiliation and Stress-Related Behavior of Long-Tailed Macaque Aggressors

Previous studies on macaques and baboons showed that after agonistic conflicts aggressees as well as aggressors show an increase in stress-related behavior such as scratching. Reconciliation reduces stress-related behavior of the aggressee. We investigated the influence of various affiliative postconflict behaviors of the aggressor on the aggressor's scratching rates in captive long-tailed macaques: reconciliation, contacts with the aggressee's kin (or substitute reconciliation), and contact with other group members (or triadic affiliation). After a conflict, the aggressor showed an increase in rates of scratching. Scratching rates were reduced after reconciled conflicts compared to nonreconciled conflicts. Substitute reconciliation did not reduce scratching when we controlled for the influence of reconciliation, i.e., the aggressor might not interpret it as a substitute for reconciliation. Triadic affiliation did not reduce scratching rates, hence, triadic affiliation probably does not console the aggressor. Scratching rates after reconciliation are significantly lower than scratching rates after triadic affiliation. This proves that the stress-reducing effect of reconciliation is not due to the calming effect of general body contact but that the stress reduction is specifically associated with contacts with the former opponent. The contestants are anxious about their relationship, and only reconciliation takes away this anxiety. Reconciliation is thus an important social repair strategy.     

The effects of temporary removal of the alpha male on the behavior of subordinate male vervet monkeys

The effects of temporary removal of the alpha male on the behavior of subordinate adult male vervet monkeys were evaluated. Twelve subordinate males from six captive multimale, multifemale vervet monkey groups were observed in two conditions: when all group members were present and when the alpha male was temporarily removed from each group. In the absence of the alpha male, subordinate males initiated more affiliative behavior and increased the amount of time spent in proximity to females but their rates of aggression were unaltered. Increased affiliative behavior was selectively directed to high-ranking females and their offspring. Under removal conditions, subordinate male behavior did not resemble that of alpha males in intact conditions: they differed in their proximity to and affiliative behavior towards other group members. In the absence of the alpha male, females increased their aggression towards subordinate males. These observations suggest that the presence of alpha males strongly inhibits subordinate males' behavior. When the constraints of the alpha male's presence are removed, subordinate males rapidly engage in behavior that may enhance their likelihood of attaining high rank. In combination with prior studies, the data also indicate that the behaviors involved in the maintenance of high rank by alpha males differ from those subordinates use to acquire dominance. Finally the current study supports the view that aggression by female vervets may be highly influential in determining male ascendency to dominant rank.     

Influence of kinship and spatial density on reconciliation and grooming in rhesus monkeys

Some cercopithecine primates direct disproportionate amounts of grooming, huddling, and agonistic support toward maternal kin. Disproportionate amounts of aggression are also directed toward maternal kin, however, suggesting that mechanisms that restore relationships damaged by aggression, such as reconciliation, might be biased toward these preferred social partners. Studies investigating kinship effects and reconciliation are inconsistent, however, perhaps because of differences in the environmental conditions under which behavior was observed. In order to test the effects of kinship and spatial density on affiliative and reconciliation behavior, we conducted focal and scan sampling on a group of rhesus monkeys (Macaca mulatta) living in an outdoor corral under low spatial density conditions. We then compared this data to previously published data on a group of the same species living under higher spatial density conditions. Neither overall grooming nor reconciliation were affected by spatial density once correction procedures were applied. Grooming was kin biased at both study sites, whereas reconciliation was kin biased only in the low-density group. Although data failed to support a Coping Model according to which grooming and reconciliation should go up under higher densities, we suggest that coping may be reflected not so much in overall rates of behavior but in strategic partner choices, such as the increased importance monkeys under crowded conditions appear to attach to nonkin partners. © 1996 Wiley-Liss, Inc.     

Conflict and postconflict behaviour in captive black-and-white snub-nosed monkeys (<Emphasis Type="Italic">Rhinopithecus bieti</Emphasis>)

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) have almost never been the subject of any behavioural observations in captivity. This study was aimed at providing preliminary information about agonistic and reconciliation behaviour in a group kept at the Kunming Institute of Zoology in China. Established procedures were used for this investigation (i.e., the postconflict/matched-control method and the time-rule method). Intra-group aggression rates were quite low. Postconflict affiliation as well as selective attraction of former opponents to each other following conflicts was demonstrated. Former opponents contacted each other earlier in postconflict periods than in matched-control periods. The average conciliatory tendency of all focal individuals combined was 54.5%. After an agonistic interaction, the first affiliative contact between former aggressors usually took place within the first minute. The behaviours most often shown as first affiliations after a conflict were body contact, mount, touch, and hold-lumbar, of which the latter is an explicit reconciliatory gesture. Furthermore, the adult male intervened non-aggressively in 84% of all conflicts (n=25) among the adult females. Overall, the patterns of aggression and reconciliation observed in R. bieti bear many of the traits that characterise tolerant primate species.     

Canine Reconciliation and Third‐Party‐Initiated Postconflict Affiliation: Do Peacemaking Social Mechanisms in Dogs Rival Those of Higher Primates?

Conflicts over food, access to mates, or other limited resources can sometimes escalate into aggression. In species that form social groups, these aggressive conflicts can jeopardize the benefits of group living, such as enhanced access to valued resources, necessitating the development of behavioural mechanisms that either mitigate conflicts, prevent aggressive escalation or resolve disputes. Two important mechanisms for managing the effects of disputes involve postconflict (PC) affiliative behaviour, either between the former opponents (called ‘reconciliation’) or between one opponent and a third party. Even though numerous studies have tested reconciliatory and third‐party affiliation tendencies in primates, for non‐primate animals little systematic data are available. We performed behavioural observations on three groups of captive domestic dogs (Canis familiaris) and used a PC/MC method to test the existence of reconciliation and third‐party affiliation in this species. The results of this study clearly indicate that both reconciliation and third‐party PC interactions are present in the domestic dog, and form important social mechanisms of the domestic dog. Furthermore, familiar individuals showed a significantly higher proportion of reconciled conflicts than did unfamiliar individuals, and also displayed fewer conflicts. Finally, we show that most of the third‐party affiliations involve the victim of a conflict and that victim‐directed affiliation outweighs victim‐initiated third‐party affiliation in these PC interactions.     

Post‐conflict third‐party affiliation in chimpanzees: what's in it for the third party?

Affiliative behavior after conflicts between conflict participants and other group members is common in many primate species. The proposed functions for such triadic interactions are numerous, mostly concerning the benefit for the former conflict opponents. We investigated post‐conflict third‐party affiliation (TPA) in captive chimpanzees (Pan troglodytes) with the aim of assessing what the affiliating third parties may gain from affiliation. Specifically, we tested whether third‐party‐initiated affiliation protects the third parties from further aggression by conflict opponents. We found support for this “self‐protection hypothesis,” in that third parties selectively directed affiliation to those opponents who more often gave further aggression to them, and affiliation effectively decreased their chance of receiving aggression from these opponents. However, a subset of affiliation, provided to conflict victims by their own kin, appeared to not be self‐protective and the function of it remained open. We conclude that chimpanzee third‐party‐initiated affiliation is a more heterogeneous behavior than thus far assumed. Am. J. Primatol. 71:409–418, 2009. © 2009 Wiley‐Liss, Inc.     

Behavioral interactions of adult females of the common shrew (Sorex araneus) with conspecifics on familiar territory

Interactions of overwintered females with conspecifics (??5 days) on familiar territories were studied experimentally. In interactions of the resident females with unfamiliar overwintered females (28 experiments), there were no differences related to the reproductive status of both parties. Between the behavior of the residents and aliens, there were no significant differences, except the refusals of contacts??and aliens had more of it. Identification and affiliative behavior and the presence of ritualized aggression was noted. There was little direct aggression. Females were sharply aggressive toward the overwintered males (23 experiments) regardless of their reproductive status. Males tried to avoid contacts. Identification and affiliative behavior were rare. Toward yearlings (25 experiments), females that participated in reproduction were aggressive (direct aggression prevailed) but singles (9 experiments) were not.     

Reconciliation and consolation in captive bonobos (Pan paniscus)

Although reconciliation in bonobos (Pan paniscus) has previously been described, it has not been analyzed heretofore by the postconflict (PC) match-control (MC) method. Furthermore, although reconciliation has been investigated before in this species, consolation has not. In this study we analyzed agonistic and affiliative contacts in all sex-class combinations to clarify and reevaluate the occurrence of reconciliation in bonobos via the PC-MC method. We also investigated the occurrence of consolation by analyzing the victims' triadic contact tendency (TCT), the influence of the sex of victims, and the relative occurrence of consolation and reconciliation. We collected 167 pairs of PC-MC observations in a captive group of bonobos (in Apeldoorn, The Netherlands). The conciliatory tendency (CCT) we obtained was tendentially lower than the mean value previously found for Yerkes captive chimpanzees. Close relationships, which were present in all female-female (FF) and some male-female (MF) dyads, positively affected reconciliation rates. When only adult PC-MC pairs (157) were considered, the mean TCTs and CCTs did not differ significantly. When we focused on types of PC affiliative contact, in the case of consolation we found a striking preference for sociosexual patterns. As to the relative occurrence of consolation and reconciliation, the highest level of the former was found in the absence of the latter. When reconciliation took place, consolation generally preceded it, suggesting that consolation may be a substitutive behavior. Our findings suggest that even if reconciliation remains the best option, consolation may be an alternative substitute for reconciliation that is used to buffer the tension originating from an unresolved conflict. Reconciliation and consolation are complex phenomena that are probably related to the life history of a group. Given that few studies have been conducted on this subject, we can not at this time make any generalizations regarding conflict resolution in certain species by comparing results among studies.     

Impaired reconciliation in rhesus macaques with a history of early weaning and disturbed socialization

An attempt had been made to create five social groups from rhesus macaques with a history of early separation from their mothers, early weaning and hand feeding and, in most cases, previous housing in single cages. We investigated the exchange of affiliative behaviours after an aggressive encounter and selective attraction to the former opponent, a phenomenon previously well described in rhesus monkeys and called reconciliation. Evidence for reconciliation was only found in one of the five groups studied (corrected conciliatory tendency=13%). This group consisted of younger animals that had, at least temporarily, been living together after separation from their mothers. In the other groups studied, containing animals with a varied background, aggressive interactions were not followed by affiliative behaviours or attraction between former opponents. Our results indicate that the use of reconciliatory behaviours in adult monkeys is dependent upon social training. Lack of functional reconciliation might be one of the explanations to the severe and uncontrolled aggression previously found in groups of rhesus macaques created from animals with disturbed early socialization.