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Rates of reconciliation vary widely between different types of opponents, and post‐conflict anxiety has been proposed to mediate individual variation in reconciliation rates. We investigated the form and function of reconciliation in a wild, provisioned group of bonnet macaques (Macaca radiata) with the prediction that sex differences in post‐conflict anxiety would be associated with sex differences in conciliatory tendency. Individuals in the study group had a conciliatory tendency of 29.3%. Victims avoided their former opponents at a higher rate following aggression than during matched‐control samples, and reconciliation decreased the rate of avoidance. Although victims showed a higher rate of anxiety‐related behavior than did aggressors, anxiety‐related behavior was elevated after aggression and reduced following reconciliation in both victims and aggressors. Female–female opponents showed higher rates of anxiety‐related behavior before reconciliation than they did following unreconciled aggression. In contrast, male–male and female–male opponents showed increased anxiety‐related behavior following aggression regardless of the occurrence of reconciliation. Moreover, female–female opponents had a higher conciliatory tendency than did female–male opponents. The elevated post‐conflict anxiety shown by female–female opponents before reconciliation, along with their high conciliatory tendency, suggests that post‐conflict anxiety promotes reconciliation. In sum, the sex differences in post‐conflict behavior found in this study support the hypothesis that variation in post‐conflict anxiety mediates differential rates of reconciliation.

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Existing models of attachment do not explain how death of offspring affects maternal behavior. Previous descriptions of maternal responsiveness to dead offspring in nonhuman anthropoids have not expounded the wide variation of deceased-infant carrying (DIC) behavior. Through the current study, we attempt to (a) identify determinants of DIC through a systematic survey across anthropoids, (b) quantitatively assess behavioral changes of mother during DIC, and (c) infer death perception of conspecifics. Firstly, we performed phylogenetic regression using duration of DIC as the dependent variable. Secondly, we undertook case studies of DIC in the bonnet monkey and the lion-tailed monkey through behavioral sampling. Results of phylogenetic Generalized Linear Mixed Model (Nspecies = 18; Ncases = 48) revealed a strong homology (H2 = 0.86). We also obtained a high intraspecific variation in DIC and found DIC to be affected by mother’s age, context of death, habitat condition, and degree of arboreality. We found bonnet mothers to carry their deceased offspring for 3.56 ± 4.03 SD days (N = 7) with diminished feeding, enhanced passivity, and social isolation during DIC and progressive decline in protection/attentiveness of corpse and attachment. Following Anderson (2016)’s framework of death perception, we interpreted repeated sensory investigation of corpses by mothers as comprehending causality of death, inanimate handling of corpse and its defense as comprehension of non-functionality, and a progressive disinterest of mothers in them as perceiving irreversibility of death. Lastly, we integrated DIC with mother-infant attachment theories and proposed a conceptual model characterizing DIC with causal determinants.

This study reports critical changes in the behaviour patterns of lion-tailed macaques (Macaca silenus) inhabiting a continuously changing and deteriorating rain forest fragment in the Western Ghats, India. The study area, a privately owned rain forest patch in a tea/coffee garden called Puthuthotam, has suffered two massive selective logging episodes. Over the years, the native rain forest trees have been largely replaced by non-native/pioneer species resulting in loss of canopy contiguity and significant changes in other vegetation parameters. The almost wholly arboreal lion-tailed macaque now spends a considerable amount of time on the ground in this area. The species has also experienced a major shift in its diet, ranging patterns and other activities.