Dyadic and triadic reconciliation in pigtail macaques (Macaca nemestrina)

The tendency in primates for former antagonists to approach and affiliate following aggression has been termed reconciliation because the response is thought to resolve social conflicts produced by aggression. In primate societies, however, an aggressive interaction between two individuals often spreads to include other group members, especially the kin of the combatants. If post conflict affiliation resolves aggressive conflicts in a group, then affiliative increases might occur between combatants and the kin of their opponents following aggression as well as between former opponents. This hypothesis was tested in a captive group of 39 pigtail macaques (Macaca nemestrina) by comparing affiliative response frequencies of combatants during the 5 minute period following aggression to affiliative response frequencies during 5 minute baseline periods not preceded by aggressive activity. Following aggression, affiliation rates increased between combatants and their opponents, aggressors and the kin of their opponents, and aggressors and their own kin. Additional analyses showed that aggression among kin was reconciled more often than aggression among nonkin. Recipients of aggression reconciled with their attackers more often than aggressors reconciled with their victims. Animals with similar dominance ranks reconciled proportionately more often than those with large rank disparities and aggressive infractions of a calculated dominance hierarchy were reconciled more often than attacks consistent with the hierarchy. Results suggest that both dyadic and triadic reconciliations occur in M. nemestrina and that compared to other primate species M. nemestrina exhibit a moderate-to-high conciliatory tendency.     

Aggression in adult male primates: A comparison of confined Japanese macaques and free-ranging olive baboons

The frequencies and types of adult male aggressive behavior of confined Japanese macaques (Macaca fuscata)and free-ranging olive baboons (Papio anubis)were compared. The baboons, which do not have a mating season, were more aggressive to conspecific males than were the macaques during their nonmating season. The baboons also solicited aid during aggressive encounters more frequently than the macaques. However, during their mating season, the macaques were more aggressive to conspecific females than were the baboons. The macaques were also involved in more triadic sequences of aggression, and the frequency of occurrence of these patterns supported Chase’s theory of dominance hierarchy formation and maintenance. The differences in aggressive behavior appeared to be related to the seasonal reproductive cycle of the macaques.     

Play behavior in immature moor macaques (Macaca maura) and Japanese macaques (Macaca fuscata)

Play is widespread across mammalian taxa, but species strongly vary in the ways they play. In less despotic primate species (i.e., with less steep dominance hierarchies, less severe conflicts, and more reconciliation), play has been described as being more frequent, cooperative, and freely expressed. To study the link between social play and dominance style, we compared play behavior in free-ranging infants, juveniles and subadults of more despotic Japanese macaques (Macaca fuscata, N = 24) and less despotic moor macaques (Macaca maura, N = 17). We found interspecific differences in play behavior that corresponded with the contrasting dominance styles of the study species, largely confirming our predictions. In particular, moor macaques spent a larger proportion of time in solitary and social play than Japanese macaques, while Japanese macaques spent a larger proportion of time in grooming interactions. In moor macaques, play sessions included more players, a larger variety of play behaviors, greater play face rates, a greater proportion of time in contact play, and a higher rate of reciprocal play-biting than in Japanese macaques. Aggressive escalations were not common, but more frequent in Japanese macaques. Finally, a higher frequency of play faces during play sessions predicted the occurrence of more reciprocal play-bites, but not the proportion of time spent in contact play behaviors. Additional studies on other groups and species will allow a better understanding of the link between dominance style and social play.     

Dominance, aggression and physiological stress in wild male Assamese macaques (Macaca assamensis)

In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale–multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.     

Counter aggression and reconciliation in Assamese macaques (Macaca assamensis)

Patterns of aggressive and affiliative behavior, such as counter aggression and reconciliation, are said to covary in the genus Macaca; this is referred to as the systematic variation hypothesis. These behavior patterns constitute a species dominance style. Van Schaik's [1989] socioecological model explains dominance style in macaques in terms of within- and between-group contest competition. Dominance style is also said to correlate with phylogeny in macaques. The present study was undertaken to examine phylogenetic and socioecological explanations of dominance style, as well as the systematic variation hypothesis. We collected data on counter aggression and reconciliation from a habituated group of Assamese macaques (Macaca assamensis) at the Tukeswari Temple in Assam, India. The proportion of agonistic episodes that involved counter aggression was relatively low. Counter aggression, however, occurred more often among males than among females, and it was most common when females initiated aggression against males. The conciliatory tendency for this group of Assamese macaques was 11.2%. The frequency of reconciliation was low for fights among males and for fights among females, but reconciliation was particularly rare for opposite-sexed opponents. Female social relationships were consistent with the systematic variation hypothesis, and suggest a despotic dominance style. A despotic dominance style in Assamese macaques weakens the correlation between dominance style and phylogeny in macaques, but it is not inconsistent with the socioecological model. Male-female relationships were not well explained by the despotic-egalitarian framework, and males may well have more tolerant social relationships than do females. Sex differences need to be considered when categorizing species according to dominance style.     

Male Social Behavior and Dominance Hierarchy in the Sulawesi Crested Black Macaque (Macaca nigra)

In a 6-week study of the social behavior of wild Sulawesi crested black macaques (Macaca nigra), we found a linear and transitive dominance hierarchy among the six adult males in one social group. Dominance rank, as determined by the direction of supplantations, correlated strongly with percentage of time near more than four neighbors, frequency of grooming received from adult females, and percentage of time with an adult female as nearest neighbor. These results suggest that high-ranking males are socially attractive. Adult females sexually solicited high-ranking males more often than low-ranking males, but frequency of copulation was not correlated with dominance rank. Frequency and intensity of aggression between males are strongly correlated with rank distance, but aggression toward females was greatest for mid-ranking males. Males of all rank displayed significantly more aggression toward sexually receptive females than toward females in other estrous states. These data indicate that male Sulawesi crested black macaques display a social organization similar to that reported for multimale groups in other macaque species rather than the egalitarian social organization described for female Sulawesi macaques.     

Grooming and aggression in captive Japanese macaques

This study investigated the relations between allogrooming and aggression in a captive group of Japanese macaques (Macaca fuscata). Our aim was to test whether evidence of an interchange between allogrooming and a reduction in aggression could be identified at a group level. Female Japanese macaques did not direct less aggression to those group mates that groomed them most. Although generally they did not direct more grooming to those group mates that attacked them most, they did show increased grooming towards those nonkin group mates that showed the most aggression. These results are interpreted in light of the conflicting processes that are likely to underlie macaque social choices.     

Affiliative and submissive communication in rhesus macaques

This study analyzed the occurrence of selected facial expressions, gestures, and postures, in relation to sex and rank of sender and receiver, context, and responses elicited in a large multi-male multi-female group of rhesus macaques (Macaca mulatta) living in captivity. The group was observed for 100 hr during the mating and the birth season. Data were collected with the behavior sampling method. The bared-teeth display and the hindquarter presentation were the most prominent signals in the rhesus submissive and affiliative repertoire. Both signals were primarily displayed in response to aggression and approaches; bared-teeth in response to approaches from the front, presentation in response to approaches from the rear. Lip-smack had a submissive component like baredteeth and presentation but was more likely to be displayed by approaching individuals and followed by affiliation than these behaviors. The distribution of hip-touch and mount was different from that of bared-teeth, presentation, and lip-smack, these behaviors mostly occurring between males, irrespective of their dominance rank. Other infrequent signals and behavioral sequences were limited to specific male-female and mother-infant interactions.     

Vocal communication of tonkean macaques in confined environments

Vocal recordings of one semi-free-ranging group and one captive group of Tonkean macaques (Macaca tonkeana) were used to establish the vocal repertoire of the species. Only the alpha male of the groups uttered a very distinctive loud call. Localization variants of coo calls were found. Alarm calls given by this species were acoustically similar to those by Japanese, rhesus, and long-tailed macaques (M. fuscata, M. mulatta, andM. fascicularis). Adult females uttered a specific variant of vocalizations during sexual morphological changes. The repertoire of agonistic vocalizations was more variable than that of any other macaque species investigated. These characteristics were discussed with reference to previous studies on vocalizations of macaque species.     

Dominance,aggression and physiological stress in wild male Assamese macaques (Macaca assamensis)

In group-living animals relative rank positions are often associated with differences in glucocorticoid output. During phases of social stability, when dominance positions are clear and unchallenged, subordinates often face higher costs in terms of social stress than dominant individuals. In this study we test this prediction and examine additional potential correlates of stress, such as reproductive season, age and amount of aggression received in wild, seasonally breeding Assamese macaques (Macaca assamensis). During a mating and a non-mating season we collected 394 h of focal observational data and 440 fecal samples of six adult and six large subadult males living in a multimale–multifemale group in their natural habitat in northeastern Thailand. The mating season was characterized by a general increase in aggressive behavior and glucocorticoid excretion across all males compared to the non-mating season. Among adult males, mating season glucocorticoid levels were significantly negatively related with dominance rank and positively with the amount of aggression received. Both relationships were non-significant among large subadult males. Thus, our results suggest that in adult Assamese macaques a high dominance position is not associated with high costs. Low costs of dominance might be induced by strong social bonds among top-ranking males, which exchange frequent affiliative interactions and serve as allies in coalitionary aggression against potentially rank-challenging subordinate males.     

Social communication among captive stump-tailed macaques (Macaca arctoides)

I compared the frequency of occurrence, contextual usage, and meaning of some of the most prominent gestural signals in stump-tailed macaques. I recorded the occurrence of 15 visual and tactile behavior patterns in a multimale multifemale captive group of stump-tailed macaques with the behavior sampling method in 100 hr of observation and analyzed the data via factor analysis and analyis of variance. The hindquarter presentation was the most frequent gesture. It was displayed by subordinates to appease dominants even in the absence of impending risk of aggression. Bared-teeth, lip-smack, teeth-chatter, and present-arm are submissive signals as well, but they differ from the presentation and from one another in their contextual usage. Nonthrusting mount, hip-touch, hip-clasp, and genital manipulation are directed down the hierarchy and appear to reflect dominance, reassurance, protection, or bonding. Mock-bite is a ritualized aggressive behavior pattern, often used to resolve uncertain dominance relationships. Ventroventral embrace occurs as a female bonding pattern. Overall, most gestural signals in stump-tailed macaques relate to dominance and submission and, to a lesser extent, social bonding.     

The evolution of “egalitarian” and “despotic” social systems among macaques

Recent studies of captive macaques have revealed considerable inter-species differences in dominance styles among females. In “egalitarian” species such as stumptail (Macaca arctoides) or tonkean macaques (M. tonkeana), social interactions are more symmetrical and less kin-biased than in “despotic” species such as Japanese (M. fuscata) or rhesus macaques (M. mulatta). Field observations of moor macaques (M. maurus), close relatives of tonkean macaques, suggest that tolerance during feeding characterizes their egalitarian dominance style in the natural habitat. Although it has been proposed that communal defense against other groups may be the main selective force in the evolution of egalitarian dominance style among females, few field data support this prediction. A game theory analysis showed that both an “egalitarian” strategy and a “despotic” strategy are possible evolutionarily stable strategies (ESS) under certain conditions. The difference in dominance styles might reflect the difference in ESS. This means that an egalitarian dominance style can emerge without strong between-group contest competition. A phylogenetic comparison among macaques suggests that despotic dominance styles very likely evolved from egalitarian dominance styles. In the future, primate socioecological studies should pay more attention to the evolutionary history of each species.     

Patterns of sexual behavior in male macaques

One large social group of each of three species of macaques (Macaca mulatta, M. fascicularis, M. radiata), housed in half-acre field cages at the California Primate Research Center, were observed for a total of 150 h. Data on sexual behavior and dominance interactions were recorded by pairs of experienced observers using a focal animal technique. Single or multiple mount-to-ejaculation sequences, number of thrusts per mount, number of mounts per sequence, duration of mounts per sequence, duration of sequences, social rank and frequency of sexual activity were recorded for each adult male. M. mulatta used a multiple mount-to-ejaculation (MME) pattern in 91% of their copulations. M. radiata used a single mount-to-ejaculation (SME) pattern in 91% of their copulations. M. fascicularis used both patterns—53% MME and 47% SME. A positive correlation was found between rank and sexual activity in fascicularis and mulatta males. A negative correlation between rank and sexual activity was found in radiata males and also a positive correlation between rank and age indicating that the youngest and most subordinate radiata males were the most sexually active males. In reviewing the literature, a relationship between degree of intermale competition, intermale tolerance and type of mounting pattern was revealed. Macaque species that primarily use an SME pattern also show sa high degree of intermale tolerance and little interrnale competition. Macaque species that primarily use an MME pattern typically show a high degree of intermale competition and a low degree of intermale tolerance. Possible events leading to such relationships are discussed.     

成年黄山短尾猴雌性等级结构稳定性

等级结构稳定性是衡量群体凝聚力的重要指标,雌性等级结构稳定对于母系社会群体具有重要的生物学意义。本文采用目标动物取样和全事件记录相结合的方法,研究黄山短尾猴鱼鳞坑A1 群(YA1 群)和鱼鳞坑A2 群(YA2 群)的成年雌性分别在交配季节(2011 年9 ～ 12 月)和非交配季节(2012 年2 ～ 5 月)内的攻击-屈服行为。采用等级结构中雌性间攻击- 屈服频率、社会顺位和等级梯度3 个量化指标,首次定量探讨了短尾猴雌性等级结构及其稳定性。研究期间,YA1 群和YA2 群雌性间攻击- 屈服频率、社会顺位和等级梯度均无季节性变化(P >0. 05)。结果表征短尾猴雌性等级结构趋于稳定,该结果支持了短尾猴雌性等级结构稳定性的定性判断。     

Formal biting in stumptailed macaques (Macaca arctoides)

Form and function of a specific kind of biting were studied in a captive group of stumptailed macaques (Macaca arctoides) composed of 1 adult male and 10 females. Behavior patterns were recorded with all occurrence and scan sampling techniques. Formal biting consisted of slowly gripping with teeth a part of the body of an apparently willing partner, most often the forearms, lips, or eyebrows. It may occur either following an agonistic interaction or outside the context of aggression. Such biting was directed from dominants towards subordinates, and appeared especially frequently between individuals having frequent agonistic interactions. It is concluded that this behavior represents a ritualized interaction expressing formal dominance between partners.     

Social Relationships in Free-Ranging Male Macaca arctoides

Macaque social relationships differ greatly between species. Based on captive studies that focus mainly on females, researchers have classified stumptail macaque (Macaca arctoides) social relationships as tolerant, as indicated by a high rate of affiliation, frequent aggression, and symmetrical conflicts. To accumulate more data on male social relationships, which are relatively understudied, and to generate comparative data, we investigated male social relationships in a provisioned group of 68 free-ranging, naturally dispersing stumptail macaques in southern Thailand. We collected continuous focal animal and ad libitum data on 7 adult and 2 subadult males, recording social behavior during 283 contact hours between December 2006 and March 2007. Stumptail macaques of this population were less tolerant than predicted based on previous studies on captive groups: Rates of spatial proximity, affiliation, and aggression were low, most males directed affiliative behavior toward higher-ranking males, and conflicts were generally of low intensity and relatively asymmetrical. Thus, male stumptail macaques of the focal group appear to differ in their social style from a previous study of a captive group that mainly comprised of females. In some traits, they are even more intolerant than rhesus macaques, an intensively studied intolerant macaque species. We also compare our data on stumptail macaque males to those on other male macaques, but available data are too sparse to draw final conclusions.     

Evaluating Dominance Styles in Assamese and Rhesus Macaques

Researchers have suggested that several types of agonistic and affiliative behavior covary as a set of species-specific traits, and have used the term dominance style to describe the covariation. We compared measures of dominance style between a group of Assamese macaques (Macaca assamensis) and a group of rhesus macaques (M. mulatta), though kinship information was unknown. Assamese and rhesus female-female dyads each showed a low proportion of counter aggression and a low conciliatory tendency, suggesting that they have despotic social relationships. They also showed a despotic pattern on several other types of agonistic and affiliative behavior, such as approach outcomes and grooming distributions, which is consistent with the covariation of dominance style traits. Assamese male-male dyads showed relatively high levels of reconciliation and counter aggression versus other macaque males portrayed in the literature, suggesting that Assamese males have a tolerant dominance style. Insofar as macaque dominance style depends on the behavior of females, we suggest that Assamese macaques, like rhesus macaques, have despotic social relationships, which contrasts with evidence of a strong correlation between phylogeny and dominance style in macaques. Further, our results indicate that strong male bonding and tolerant dominance relationships among males are independent of female dominance style. Lastly, some measures of agonistic behavior, such as rate of aggression or proportion of bites, are likely altered in competitive environments and thus are not useful indicators of dominance style.     

Cranial adaptation to a high attrition diet in Japanese macaques

Primates with diets that require greater occlusal forces to process exhibit anteroposteriorly shorter, vertically deeper faces, more anteriorly placed masseter attachment areas, and broader, taller mandibular corpora compared to closely related species/populations. Japanese macaques (Macaca fuscata)eat different, perhaps mechanically tougher to process, foods than other macaques do. Accordingly, they should exhibit structural features of the skull related to dissipating great occlusal loads. To test this hypothesis I compared cranial variables amongst wild-caught, adult female skulls (n = 85) of M. fuscataand three other macaque species (M. mulatta, M. fascicularis,and M. nemestrina)and applied least-squares and reduced-major-axis regression analysis and principal components analysis (PCA) to 17 cranial variables reflecting facial, vault, and mandibular dimensions. When scaled for size, the Japanese macaque has a vertically deeper and anteroposteriorly shorter face,a broader but not taller mandibular corpus, and a more anteriorly placed masseter muscle than the other three macaques do. The first PCA axis isolates variation due to a suite of characters related to mechanical efficiency in dissipating occlusal loads (vertically deep face and broad corpus) and differentiates the Japanese macaques from the other species. This, coupled with reported dietary differences among species, suggests that Japanese macaques are selected for dissipating greater occlusal loads than other macaques are. The presence of a narrow mandible relative to cranial breadth and a hyperrobust mandibular corpus width suggests that axial torsion is a significant influence in the masticatory regime of M. fuscata.The lack of an increase in corpus height indicates that parasagittal bending is not as significant an influence. Geographic and climatic influences cannot account for the patterns of variation between M. fuscataand the other macaques.     

Polyspecific groups of macaques on the kowloon peninsula,new territories,Hong Kong

Three polyspecific groups of free-ranging macaques were observed in July and August of 1980 and 1981 in the forests of the New Territories of mainland Hong Kong. Two groups were composed of rhesus monkeys (Macaca mulatta) and long-tailed or crab-eating monkeys (M. fascicularis), and one group was composed of both the former plus Japanese macaques (M. fuscata). All three groups contained hybrids between M. mulatta and M. fascicularis. This combination of species within the same social group is an unusual circumstance in natural habitats, and it offers a unique opportunity for field studies in primate ecology and behavior.