Heart Rate during Conflicts Predicts Post-Conflict Stress-Related Behavior in Greylag Geese

Background: Social stressors are known to be among the most potent stressors in group-living animals. This is not only manifested in individual physiology (heart rate, glucocorticoids), but also in how individuals behave directly after a conflict. Certain ‘stress-related behaviors ’ such as autopreening, body shaking, scratching and vigilance have been suggested to indicate an individual’s emotional state. Such behaviors may also alleviate stress, but the behavioral context and physiological basis of those behaviors is still poorly understood. Methodology/Principal Findings: We recorded beat-to-beat heart rates (HR) of 22 greylag geese in response to agonistic encounters using fully implanted sensor-transmitter packages. Additionally, for 143 major events we analyzed the behavior shown by our focal animals in the first two minutes after an interaction. Our results show that the HR during encounters and characteristics of the interaction predicted the frequency and duration of behaviors shown after a conflict. Conclusions/Significance: To our knowledge this is the first study to quantify the physiological and behavioral responses to single agonistic encounters and to link this to post conflict behavior. Our results demonstrate that ‘stress-related behaviors’ are flexibly modulated by the characteristics of the preceding aggressive interaction and reflect the individual’s emotional strain, which is linked to autonomic arousal. We found no support for the stress-alleviating hypothesis, but we propose tha

Post-conflict affiliation as conflict management in captive bottlenose dolphins (Tursiops truncatus)

Post-conflict affiliation between former opponents or between one of the former opponents and bystanders might have the function of conflict management, which reduces the costs associated with aggressions. One of the suggested functions of post-conflict affiliation is decreased renewed aggressions directed from aggressors to victims. However, the effect of post-conflict affiliation on renewed aggressions by victims has not been investigated. We examined whether post-conflict affiliations decreased the number of renewed aggressions initiated by winners or losers in captive bottlenose dolphins. Both winners and losers initiated renewed aggressions. However, these aggressions decreased after post-conflict affiliation between former opponents, initiated by bystanders to winners, initiated by losers to bystanders, and initiated by bystanders to losers. Post-conflict affiliation between former opponents is suggested to function as reconciliation. Post-conflict affiliation initiated by losers to bystanders is suggested to function as the protection of losers. Post-conflict affiliations initiated by bystanders to one of former opponents are suggested to function as both appeasement and protection of the opponent who affiliates with bystanders

The importance of considering the behavioral form of reconciliation in studies of conflict resolution.

Reconciliation is the most extensively studied conflict resolution mechanism in animal societies. However, despite the extensive literature on this topic, behaviors considered to represent postconflict affiliation have not been consistent across studies of reconciliation. Critically, reconciliation is usually defined as postconflict contact affiliation, e.g., grooming, and the importance of including interopponent distance regulation is often neglected. Moreover, to date, no study has simultaneously investigated different behavioral forms of reconciliation. We tested in two groups of wild Barbary macaques (Macaca sylvanus) the relative importance of postconflict close proximity and grooming in the mediation of two important costs of aggression: damage to the opponent’s social relationship and elevated postconflict anxiety.We provide evidence that close-proximity approaches function to resolve conflicts: Close-proximity approaches reduced the victim’s postconflict anxiety and were predicted by the quality of the social relationship with the opponent. Moreover, postconflict grooming alone, although predicted by the quality of the opponent’s social relationship, did not influence the victim’s elevated postconflict anxiety. Our results suggest that interopponent distance regulation plays an important role in reconciling the costs of aggression in Barbary macaques. We advocate that further efforts should be made to test which behaviors play a role in conflict resolution in different species. This is important because even closely related species may differ in the function of behaviors that superficially appear to be rather similar. Moreover, the choice of behaviors used to study conflict resolution determines the frequency with which reconciliation is observed and can thus bias comparisons across species

The Function of Mounts in Free-Ranging Barbary Macaques (Macaca sylvanus)

Generally, non-reproductive sex is thought to act as “social grease”, facilitating peaceful co-existence between subjects who lack close genetic ties. However, specifc non-reproductive sexual behaviors may fulfill different functions. With this study, we aimed to test whether non-reproductive mounts in Barbary macaques are used to: (i) assert dominance, (ii) reinforce social relationships, and/or (iii) solve conflicts. We analyzed non-reproductive mounts (N = 236) and post-mount behavior in both aggressive and non-aggressive contexts, in 118 individuals belonging to two semi free-ranging groups at La Montagne des Singes (France). As predicted by the dominance assertion hypothesis, the probability to be the mounter increased with rank difference, especially in aggressive contexts (increasing from 0.066 to 0.797 in non-aggressive contexts, and from 0.011 to 0.969 in aggressive contexts, when the rank difference was minimal vs. maximal). The strength of the social bond did not significantly predict the proportion of mounts across dyads in non-aggressive contexts, providing no support for the relationship reinforcement hypothesis. Finally, in support of the conflict resolution hypothesis, when individuals engaged in post-conflict mounts, (i) the probability of being involved in further aggression decreased from 0.825 to 0.517, while (ii) the probability of being involved in grooming interactions with each other increased from 0.119 to 0.606. The strength of the social bond between former opponents had no significant effect on grooming occurrence and agonistic behavior after post-conflict-mounts. Overall, our findings suggest that non-reproductive mounts in Barbary macaques have different functions that are not affected by the strength of the social bond

Functions of an unreported “rocking-embrace” gesture between female Japanese Macaques (Macaca fuscata) in Kinkazan Island, Japan

Recently, research has focused on the effects of the concurrence of multimodal signals and their efficacy and meaning. We observed an unreported behaviour, a ventro-ventral "rocking-embrace" gesture that is always accompanied by lip smacking as the facial expression and sometimes by a girney call, in wild Japanese macaques (Macaca fuscata) living in Kinkazan Island, northern Japan. This study examined the form and contexts of the occurrence of such multimodal signals in order to elucidate its functions. Eighty-eight cases of rocking embrace were recorded during 183 h of observation over 22 days. Adult females were involved in all of the cases. Of the 71 cases between adult females in which behaviours prior to the rocking embrace could be identified, 13 cases were allogrooming interruptions, 11 were aggression, and 42 were approaches, most of which occurred between non-kin grooming partners. The rocking embrace was often followed by allogrooming. This suggests that rocking embraces occur under stressful conditions and may function to reduce tensions. This conclusion is consistent with the contexts and functions of lip smacking and girneys shown in previous studies. In contrast with lip smacking and girneys, neither a rocking embrace nor a ventro-ventral embrace (without rocking) between anoestrous adult females has been previously shown in Japanese macaques. In other macaque species, however, the latter gesture is often observed as an affiliative behaviour that immediately follows conflict; it functions to reconcile or as a greeting when it occurs immediately after an approach. Rocking embraces among the Kinkazan macaques occur in contexts similar to, and have a similar function to, the ancestral gesture of ventro-ventral embracing (which is hidden in Japanese macaques) and the ancestral display of lip smacking (which is still observed in Japanese macaques). The ventro-ventral embrace as a tactile signal might have been hidden since it was made redundant by the visual signal of lip smacking in ancestral macaques