Reconciling with valuable partners by long-tailed macaques

In primates and other social mammals, opponents in aggressive conflicts have been reported to seek one another out after fights for various types of friendly interaction. In long-tailed macaques, these friendly reunions have been shown to restore aspects of the social relationship of the opponents to their preconflict state, and they have thus been interpreted as reconciliations. Although postconflict reconciliation would seem to be adaptive to gregarious animals that establish individualized social relationships, its occurrence is variable among species, groups and dyads. Some of this variation probably reflects costs and benefits of reconciling in different situations. One factor that might influence the benefit of reconciliation and hence its occurrence is the value of the social partner as a social or ecological resource: reconciliation should occur more often after fights with valuable social partners. We conducted an experiment to test this hypothesis using pairs of monkeys (Macaca fascicularis) as their own controls. First, baseline rates of reconciliation after experimenter-induced conflict were measured. Then, the value of the relationship, at least in the test context, was increased by training each pair of monkeys to perform a simple cooperative task in which each got access to food only if the partner fed nearby simultaneously. Finally, the reconciliation rate was measured again after training and compared to its baseline value. In 6 of 7 dyads, the reconciliation rate increased after training, and the median reconciliation rate after training was 3 times higher than at baseline. While the results are consistent with the value hypothesis, there are other potential explanations. Comparison of friendly behavior when there had been no prior aggression in baseline and post-training phases, however, suggested that the increase in reconciliation rate was neither the result of a general increase in compatibility nor the result of anticipated conflict in the cofeeding context.

[1]  Filippo Aureli,et al.  Post-conflict Behaviour in Long-tailed Macaques (Macaca fascicularis): II. Coping with the Uncertainty , 2010 .

[2]  The reconciliation behavior of golden monkeys (Rhinopithecus roxellanae roxellanae) in small breeding groups , 1991, Primates.

[3]  T. Rowell,et al.  Reconciliation following aggression in patas monkeys, Erythrocebus patas , 1988, Animal Behaviour.

[4]  M. Yamada.  A study of blood-relationship in the natural society of the Japanese macaque , 1963, Primates.

[5]  M. Cords.  On operationally defining reconciliation , 1993, American journal of primatology.

[6]  R. Seyfarth,et al.  Social relationships and social cognition in nonhuman primates. , 1986, Science.

[7]  P. Judge.  Dyadic and triadic reconciliation in pigtail macaques (Macaca nemestrina) , 1991, American journal of primatology.

[8]  F. Waal,et al.  Reconciliation and consolation among chimpanzees , 1979, Behavioral Ecology and Sociobiology.

[9]  F. Waal,et al.  Comparison of the reconciliation behavior of stumptail and rhesus macaques , 2010 .

[10]  O. Rasa.  The Ethology and Sociology of the Dwarf Mongoose (Helogale undulata rufula) , 1977, Zeitschrift für Tierpsychologie.

[11]  R. Seyfarth,et al.  Redirected aggression and reconciliation among vervet monkeys, Cercopithecus aethiops , 1989 .

[12]  F. Waal,et al.  Reconciliation and Redirected Affection in Rhesus Monkeys , 1983 .

[13]  H. Kummer,et al.  On the value of social relationships to nonhuman primates: A heuristic scheme , 1978 .

[14]  Affiliation and reciprocity in sibling and peer relationships among free-ranging immature male rhesus monkeys , 1985, Animal Behaviour.

[15]  F. Waal,et al.  The Integration of Dominance and Social Bonding in Primates , 1986, The Quarterly Review of Biology.

[16]  Filippo Aureli,et al.  Post-conflict Behaviour in Long-tailed Macaques (Macaca fascicularis): I. The Social Events , 2010 .

[17]  M. Cords.  Post-conflict reunions and reconciliation in long-tailed macaques , 1992, Animal Behaviour.

[18]  M. Cords.  Resolution of aggressive conflicts by immature long-tailed macaques Macaca fascicularis , 1988, Animal Behaviour.

[19]  H. Kruuk,et al.  COMPARATIVE NOTES ON PREDATION BY LION, LEOPARD, CHEETAH AND WILD DOG IN THE SERENGETI AREA, EAST AFRICA , 1967 .

[20]  C. V. van Schaik,et al.  Functional aspects of reconciliation among captive long‐tailed macaques (Macaca fascicularis) , 1989, American journal of primatology.

[21]  F. Waal.  Class structure in a rhesus monkey group: the interplay between dominance and tolerance , 1986, Animal Behaviour.