Group living primates utilise a number of characteristic post-conflict behaviours as a means of regulating the impact of escalated intragroup disputes. Although immature group members are typically implicated in disproportionate levels of aggression in many cercopithecine taxa, the conflict management abilities of young animals remain relatively unstudied as most previous investigations have focused solely upon adults or pooled data across age classes. This study therefore utilised a cross-sectional design to examine the immediate consequences of aggressive confrontations and the patterning of both affiliative and agonistic post-conflict interactions with former opponents and previously uninvolved bystanders, in free-ranging immature rhesus macaques (Macaca mulatta) at Cayo Santiago, Puerto Rico. Subjects of both sexes (n = 108) and between 1 and 4 years of age were drawn from two social groups, upon which 451 pairs of 10-minute post-conflict and matched-control observations were collected over a 10 month period in 1996. These data were supplemented by 10-minute post-conflict intervals extracted from an additional 432 hours of continuous focal observations conducted upon a balanced subset of 36 juveniles, together with a total of 549 group-wide scan samples concentrating upon affiliative behaviour. Involvement in aggression was found to have both social and ecological costs for former victims, which were subject to elevated rates of subsequent threats and attacks in the minutes following a conflict, a period in which they also spent more time in locomotion and less time upon feeding. Nevertheless the behaviour of aggressors was also affected, as contestants in both roles exhibited some degree of post-conflict elevation in self- (e.g. scratching) and object-directed activities (e.g. gnawing or manipulating) likely to be indicative of tension or anxiety, although these increases were often more pronounced in the recipient as opposed to the perpetrator of aggression. Affiliative reunions between former adversaries in the wake of aggression were demonstrable in even the youngest subject cohort and the patterning of these "reconciliatory" events was similar to that documented in previous work on adult macaques, with the context of the preceding conflict (over food versus of no discernible cause) and the quality of relationship between the protagonists (whether close kin or favoured affiliates, or not) significantly reducing or elevating, respectively, the likelihood that a reunion would take place. In the former case, variation in conciliatory tendency was also paralleled by a difference in the degree to which rates of self-scratching were elevated under post-conflict conditions, whilst in the latter case it was not - confrontations between close associates produced levels of scratching no higher than those after a dispute between less favoured affiliates. Immature subjects were also more likely to interact with certain other partner classes under post-conflict as opposed to baseline conditions. For example, there was a pronounced increase in affiliative contacts between former coalition partners following polyadic conflicts, these overtures typically being instigated by the beneficiary of support. Affinitive interactions between both aggressors and victims and previously urtinvolved bystanders were also significantly elevated, being preferentially directed toward the contestant's close relatives and those of its opponent; the latter type of interaction appeared more frequent in the youngest subjects and partner selection was not merely a side-effect of proximity to members of the opponent's family. The degree to which kinship between former opponents, or with bystanders, influenced the likelihood of post-conflict affiliation was greater in female subjects, but the sexes behaved similarly in all other respects. Significant differences in behaviour between birth cohorts were also largely absent, although older immatures were more likely to "redirect" aggression toward third parties when victimised. These attacks against bystanders in the wake of conflicts were exhibited by both aggressors and victims, although aggressive responses were more likely when in the latter role. It is suggested that redirection by former victims may function predominantly as a signal to other group members, as these aggressive events were particularly likely to take place within view of former opponents and were associated with a high incidence of vocal threats; furthermore, redirection was associated with a significant reduction in the amount of aggression the subject subsequently received from others. Immature rhesus macaques therefore appear to possess a rich repertoire of post-conflict behaviour, in many ways resembling that reported in previous studies based upon mixed-age subject samples. However, relatively small size and on average low rank may place greater constraints upon the behaviour of juvenile group members, which therefore may need to reach a certain age or size before fully expressing their potential. Further work is now needed to ducidatc the functional cons~quences for immature contestants of the patterns of post-conflict hehaviour documented. partIcularly those involving partners other than the former opponent.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:322789 |
| Date | January 1999 |
| Creators | Kazem, Anahita Jane Nejad |
| Publisher | Durham University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.dur.ac.uk/1197/ |
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