Affiliative relationships and reciprocity among adult male bonnet macaques (Macaca radiata) at Arunachala Hill, India

In captivity, male bonnet macaques (Macaca radiata) frequently express "friendship" toward one another, including affiliative behavior such as huddling, grooming, coalitionary support, and sitting in close proximity. The purpose of this study was to determine whether wild adult male bonnet macaques also express "friendship" by investigating whether or not (1) adult male bonnet macaques have affiliative social relationships with other males, (2) the strength of social relationships varies among dyads, (3) there is time-matched reciprocity in allogrooming among dyads, and if so, whether the level of reciprocity occurs within a bout of grooming, a day, or over 2 months (the limit of this study), and (4) a correlation exists between the strength of social relationships and dominance ranks among adult males. Focal samples totaling 150 hr on all seven adult males in one study group were conducted to record both agonistic and affiliative interactions. Agonistic interactions were used to construct a dominance hierarchy, whereas affiliative interactions (sitting in proximity to within 1 m with and without grooming) were used to quantify the existence and strength of social bonds within dyads. Results show that adult male bonnet macaques had differentiated affiliative relationships with other males in their group. There was little reciprocity of grooming within a bout of grooming or within a day, but greater reciprocity over the study period of 2 months. There was no correlation between dominance ranking distance and the strength of affiliative relationship within dyads; however, within dyads lower-ranking males groomed higher-ranking males more than vice versa. This study suggests that friendships in male bonnet macaques are characterized not by immediate tit-for-tat reciprocal altruism, but by reciprocity over a longer time span, and that affiliative social relationships may be less constrained by agonistic relationships than is the case in more despotic species of macaques.     

Intertroop relationships among Japanese monkeys

Intertroop relationships among Japanese monkeys, which have been paid only scant attention for the past 20 years, are examined from several points of view. Japanese monkey troops are generally distributed in such a way as to concentrate locally, that is, to form a local concentration of troops (LCT). About 20% of the nomadic ranges of the troops within LCT's overlap; but in their natural state, they seldom approach but rather to avoid one another. From observations of intertroop encounters at Takasakiyama, where three troops are provisionized and use the same feeding place, it has been found that there exists a dominant-subordinate relationship among troops, that monkeys of each troop have a clear consciousness of belonging to their troop, and that monkeys of different troops rate one another on the basis of their capability. The frequency of male transfer between troops within LCT's is by far higher than between LCT's. In Japanese monkey society, a troop only is a social unit and a social order higher than a troop is not seen; however, it is not impossible to consider an LCT a consanguineally connected group by reason of the transfer of males among the troops within it.     

Mutual grooming and nearest-neighbor relationships among foals of Equus caballus

A 3-year study was carried out on the developmental behavior of foals from birth to 24 weeks of age and the behavior of mares living with foals. Mutual-grooming partners of foals were primarily other foals. The peak frequency of mutual grooming occurred during Weeks 9–12, when fillies mutual-groomed 1.6 times h⁻¹ and colts mutual-groomed 0.9 times h⁻¹. Fillies mutual-groomed more frequently than colts (P < 0.025). Fillies mutual-groomed randomly with colts and other fillies (P < 0.05), whereas colts mutual-groomed almost exclusively with fillies (P = 0.03). At all ages studied, if a foal's nearest neighbor was not its mother, it was more likely to be another foal than would be expected if the foal was associating randomly with non-mother ponies. Fillies were more likely than expected to have a filly rather than a colt as their nearest neighbor (P = 0.01). Thus, during their first few months of life, the foals studied exhibited patterns of behavior which were consistent with the development of the usual social milieu of unmanaged adults, in which several mares form a cohesive herd with one or more stallions associating with them.     

A model of social grooming among adult female monkeys.

Grooming networks among adult female monkeys exhibit two similar features across a number of different species. High-ranking animals receive more grooming than others, and the majority of grooming occurs between females of adjacent rank. A theoretical model which duplicates these features is presented, and the properties of the model are used to explain the possible causation and function of female grooming behaviour. The model illustrates how relatively simple principles governing the behaviour of individuals may be used to explain more complex aspects of the social structure of non-human primate groups.     

Dominance hierarchy and social grooming in female lion- tailed macaques (Macaca silenus) in the Western Ghats, India

This article reports the structure of dominance and its relationship with social grooming in wild lion-tailed macaque females. The strength of dominance hierarchy was 0.79 on a scale of 0 to 1 indicating a moderate linearity in the ranking system. Dominance scores were converted into an ordinal as well as an interval scale. Grooming scores were also converted into interval scales using standard scores. Grooming received and grooming given correlated positively and negatively respectively with dominance ranks indicating that high ranking females received more and gave less grooming. Grooming was also positively related to encounter rates for dyads of females. More grooming among adjacent ranks, and grooming being more reciprocal, occurred only in the case of dominant females. The grooming patterns, therefore, appeared to be more of despotic than egalitarian nature. While ranking macaques into different Grades of social systems ranging from despotic to egalitarian, Thierry (2004) has placed lion-tailed macaques in Grade 3 corresponding to the ‘relaxed’ social system. Our results indicate that the grooming and dominance relationships in this species are more despotic, and hence, the Grade for this species requires to be shifted toward 2 or 1.     

Dominance relationships among S-alleles in Corylus avellana L.

Summary Pollen-stigma compatibility relationship were studied in 50 cultivars and more than 800 seedlings of the European hazelnut (Corylus avellana L.). A total of 22 unique S-alleles have been identified. Dominance relationships in 75 of the possible 231 pairs of alleles have been determined in both pistil and pollen. In the pistil, all alleles exhibited independent action, whereas in the pollen, alleles exhibited either dominance or codominance. The dominance relationship was linear with 7 levels of dominance.Oregon Agricultural Experiment Station Technical Paper No. 8542     

The distribution of grooming and related behaviours among adult female vervet monkeys

Grooming and related behaviours among adult females in three groups of vervet monkeys were studied for 14 months. In all groups, high rates of grooming were significantly correlated with high rates of alliance formation and/or proximity. Females of all ranks competed more for the opportunity to groom high-ranking, as opposed to low-ranking, individuals. High-ranking females received more grooming than others and, at least partly as a result of competition, 16 of 23 females gave more grooming than expected to those of adjacent rank. Changes in grooming distributions during the eight weeks after birth were accurately predicted in four cases studied by a model based on the attractiveness of females with infants, the attractiveness of high rank, and competition.     

Interplay between various aspects in social relationships of young rhesus monkeys: Dominance,agonistic help,and affiliation

Relationships between group-living primates depend strongly on their position in the group dominance hierarchy and on their relationships with other group members. The influence of various behaviours on social relationships of immature rhesus monkeys (Macaca mulatta) was investigated here. Dominance ranks were established and related to the degree of affiliation in a dyad. Older monkeys were mostly dominant to the younger ones, regardless of kinship. Subordinate monkeys left proximity of their dominant members more often than they were left by them both among siblings and non-siblings, but the effect of dominance rank on the amount of play initiation and grooming in a dyad differed between these two types of dyads. The amount of agonistic help two individuals provided for each other was low among immatures. Nevertheless, pairs of siblings gave help to each other in agonistic conflicts more often than non-siblings, and such help was more often reciprocated between siblings than between non-siblings. Help in agonistic conflicts was positively correlated with the amount of time monkeys spent playing, grooming, or in proximity. Adults tended to interfere less in conflicts of frequent sibling play partners or non-sibling grooming partners. No evidence was found for young monkeys to exchange reciprocally grooming for agonistic help. It is argued that the time monkeys spend interacting with each other in affiliative interactions increases their familiarity and thus promotes close relationships between them. On the whole, young monkeys' relationships, like those between adults, are influenced strongly by their kinship, and position in the dominance hierarchy.     

Social interactions of juvenile female bonnet monkeys,Macaca radiata

This study reports observations on juvenile female bonnet macaques (Macaca radiata) in a field cage environment. Interaction and proximity data collected on different age classes of juvenile females indicate distinct changes in social behavior from the time a female is weaned until her first pregnancy. Behavioral development includes an increase in solitary behavior, an early disinterest in younger animals, and a surprisingly low interaction rate with relatives. Important aspects of ontogeny are lost in analyses that treat all juvenile females as a single age-class. This research was supported partially by US PHS Grant No. RR00169.     

Rank,relationships, and responses to intruders among adult male vervet monkeys

We examined the influences of dyadic relationships among captive adult male vervet monkeys (Cercopithecus aethiops sabaeus) on behavior directed toward caged “intruder” males placed inside subjects' enclosures. Subjects were all 9 adult male residents from three stable social groups, each of which contained 3 adult males, at least 3 adult females, and their immature offspring. Every male was observed in two 3-hour sessions, each time with one of the 2 other adult males from his group. Observation sessions consisted of six consecutive 30-min stages in which group composition and the presence of the intruder were manipulated. All groups exhibited a stable, linear male dominance hierarchy prior to and throughout the study. In each group, there was one pair of males, when together, in which each member exhibited higher rates of intruder-directed approach and aggressive behaviors than when either animal was paired with the third male of his social group. Such pairs were also distinguished by high levels of within-pair agonistic interactions. The higher-ranking member of each dyad was the most aggressive male toward the intruder in his social group, although only one of these animals was the dominant male of his group. Mutual facilitation of aggression against intruding males is interpreted as cooperative behavior benefitting both males by increasing the likelihood of repelling a potential competitor for resident females. Such cooperation provides further evidence in nonhuman primates for cohesive male-male dyads between animals whose social interactions are characterized by agonism. © 1993 Wiley-Liss, Inc.     

Dominance relationships among one-male units in a provisioned free-ranging band of the Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China

We studied the dominance relationships among one-male units (OMUs) in a provisioned free-ranging band of the Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains of central China from 2001 to 2005. The band was composed of 6-8 OMUs that stayed in the band for several years. Linear dominance orders could be detected using displacement interactions with directional asymmetry among OMUs in 82.3+/-5% of interactions, and ambiguous and reversed interactions in 17.7+/-5%. The dominance rank of OMUs was positively related with the duration of their stay in the band, and this may be attributed to the association of the resident male with adult females, rather than the fighting ability of resident males, as males do not fight seriously with each other. Subordinate units were observed to merge with dominant units resulting in an elevation of their rank order. The linear dominance relationship among OMUs in the Sichuan snub-nosed monkeys may have evolved as a result of competition for preferred food trees.     

Age-related differences in social grooming among adult female Japanese monkeys ( Macaca fuscata)

The present study investigated the influence of dominance rank in combination with kinship on age-related differences in social grooming among adult females in a free-ranging group of Japanese monkeys (Macaca fuscata). Eighty-three adult females were divided into six sub-groups according to age-class (younger: 5–9 years old; middle: 10–14 years old; older: 15–22 years old) and dominance rank (high and low rank). The ratio of the number of unrelated females that each female groomed to the total number of available unrelated females and grooming bouts which she gave to unrelated females decreased with increasing age for both high- and low-ranking females, whereas age did not appear to affect corresponding values for related females. On the other hand, compared with low-ranking females, high-ranking females of all age-classes received grooming more often from a larger number of unrelated females. Moreover, older females of low rank received grooming less often from a smaller number of unrelated females than younger females of low rank. These results indicate that with increasing age females are more likely to concentrate on related females when they have grooming interactions with other females. This tendency seems to be more apparent for low-ranking females. Moreover, the present findings also indicate that older high-ranking females could maintain their social attractiveness as high as younger high-ranking females.     

Dominance relationships among male hamadryas baboons (Papio hamadryas)

The concept of dominance has been shown to be useful in describing and predicting social interactions in group-living animals. However, the dominance relationships among adult hamadryas males (Papio hamadryas) are poorly understood, and systematic data are missing from the literature. This study investigated dominance relationships among male hamadryas baboons by applying novel statistical techniques to systematic detailed data on agonistic interactions. We also analyzed the dominance relationship with male age and evaluated the association between dominance and access to mating partners (i.e. the number of adult females per one-male unit (OMU)), food resources (i.e. monopolization of feeding areas), and greeting interactions. The derived dominance indexes showed that, in general, leader males were dominant over followers, and that dominance ability did not correlate with male age. Individual dominance values were very close to each other, suggesting that dominance relationships among hamadryas males were not very rigid. In addition, dominance values were positively correlated with number of adult females per OMU but not with feeding priority. Finally, greeting interactions occurred more frequently between individuals with similar dominance values and with low levels of dominance decidedness. We suggest the need of further studies, especially in wild populations, to confirm our findings.     

Reciprocity in play,grooming, and proximity in sibling and nonsibling young rhesus monkeys

Play, grooming, and proximity, and the degree to which these were reciprocated between pairs, were studied in immature sibling and nonsibling rhesus monkeys (Macaca mulatta)in four established captive groups over two seasons. “Interaction reciprocity” and “partner reciprocity” were assessed for each dyad for each of the three behaviors. In play, interaction reciprocity was based on the ratio between the play initiations by each dyad member,in grooming on the ratio between the grooming durations by each dyad member, and in proximity on the relative responsibility for proximity maintenance. Two or three most frequent (top) partners for each behavior were found for each individual. If two monkeys were among each other’s top partners, they were said to be reciprocal partners. Monkeys played with nonsiblings as much as with siblings but spent more time grooming and in proximity with siblings than with nonsiblings. Same-age nonsiblings (peers) were more frequent partners than other nonsiblings for each behavior. Siblings’ grooming interactions were more reciprocal than those of nonsiblings. There was no such effect for play and proximity. All-male dyads tended to be more reciprocal in play interactions, and all-female dyads tended to be more reciprocal in grooming interactions. In play, but not in grooming or proximity, the interaction reciprocity of reciprocal partners was higher than that of nonreciprocal dyads. It is argued that the three behaviors have similar roles in infant’s social development but they differ in the expression of this role. Hence the reciprocity patterns vary with the behavior.     

Dominance hierarchy and social relationships in a group of Captive black-and-white snub-nosed monkeys (Rhinopithecus bieti)

Different types of dominance hierarchies reflect different social relationships in primates. In this study, we clarified the hierarchy and social relationships in a one-male unit of captive Rhinopithecus bieti observed between August 1998 and March 1999. Mean frequency of agonistic behaviour among adult females was 0.13 interactions per hour. Adult females exhibited a linear hierarchy with a reversal of 10.9%, indicating an unstable relationship; therefore, R. bieti appears to be a relaxed/tolerant species. The lack of a relationship between the agonistic ratio of the adult male towards adult females and their ranks indicated that males did not show increased aggression towards low-ranking females. Differentiated female affiliative relationships were loosely formed in terms of the male, and to some extent influenced by female estrus, implying that relationships between the male and females is influenced by estrus and not rank alone. A positive correlation between the agonistic ratio of adult females and their ranks showed that the degree to which one female negatively impacted others decreased with reduction in rank. Similarly, a positive correlation between the agonistic ratio of females and differences in rank suggests that a female had fewer negative effects on closely ranked individuals than distantly ranked ones. These data indicate that rank may influence relationships between females. A steeper slope of regression between the agonistic ratio and inter-female rank differences indicated that the extent of the power difference in high-ranking females exerting negative effects on low-ranking ones was larger during the mating season than the birth season, suggesting that rank may influence the mating success of females.     

Dominance and feeding competition in captive rhesus monkeys

The feeding behavior of 16 adult female rhesus monkeys living in three captive social groups was observed. Estimates of relative food intake, feeding rate, and location of feeding in relation to food sources were compared between females of different dominance ranks. Higher-ranking females had greater access to feeding sites and were supplanted or threatened less frequently while feeding than subordinates. However, no consistent differences in estimates of total intake were found between females of high and females of low rank. The effects of dominance on feeding behavior were most pronounced in the group receiving the least food relative to estimates of overall group nutritional requirements. Higher-ranking females, both over the long term and during the study period, tended to produce more surviving offspring. The effects of dominance on reproductive performance appeared to be less related to food intake than to competitive and aggressive interactions, potentially resulting in higher levels of stress for subordinates.     

Reciprocity and partner preference in grooming of female blue monkeys

Grooming among adult and older juvenile females in a wild group of blue monkeys (Cercopithecus mitis stuhlmanni) is analyzed and related to agonistic behavior. Both grooming and agonistic behavior were less frequent than would be expected in baboon and macaque groups. Fair shares of grooming were given and taken, both within and between interactions, in amost dyads, and all females were seen to groom with at least half the others. The reciprovity of grooming was its most outstanding feature. There was no evidence that grooming was preferentially directed at kin. Frequent grooming partnerships fell into two clusters, one of which ranked higher than the other. We suggest that grooming throughout the group helps to establish a coherent team of females which effectively, defends its territory in daily encounters at the boundaries with neighboring groups.