Sources of variation in interbirth intervals among captive bonnet macaques (Macaca radiata)

Female fitness is a function of variation in the length of females' reproductive careers, the viability of their offspring, and the frequency with which they give birth. Infant loss shortens interbirth intervals in most primate species, but we know considerably less about other factors that contribute to variation in the length of interbirth intervals within groups. In one large captive group of bonnet macaques, maternal parity, age, experience, family size, and recent reproductive history are all associated with variation in the length of intervals that follow the birth of surviving infants. Primiparous females have the longest interbirth intervals, while multiparous females who have produced surviving infants in the past and have raised their last infant successfully have the shortest interbirth intervals. Infant sex and maternal rank have no direct effect upon the length of interbirth intervals. One of the underlying causes of variation in the length of interbirth intervals after surviving births seems to be variation in the timing of conceptions among females. Females who conceive early in the mating season tend to have shorter interbirth intervals than other females. However, females who are multiparous, experienced, and have recently raised infants have late conceptions and short interbirth intervals.     

Vocal communication of wild bonnet macaques (Macaca radiata)

Field observations and spectrographic analyses of sound recordings of South Indian bonnet macaques revealed a vocal repertoire of at least 25 basic patterns. The repertoire consists of well separated sound classes and acoustic categories connected by structural intergradation. Besides structural variations within and between different elements of the repertoire, the vocal system ofMacaca radiata is characterized by regular combinations of particular basic patterns. These combinations occurred not only between calls of similar structure and function but also between calls usually emitted in entirely different social contexts. According to the qualitative analysis, sex-specific asymmetries of the vocal behaviour were less pronounced than age-dependent characteristics. The comparison of clear call vocalizations ofMacaca radiata andM. fuscata revealed significant species-specific differences on the structural and the behavioural level. Evaluations of the structural features of alarm calls of various macaque species imply marked differences between members of thefascicularis group andsinica group on one hand and thesilenus group andarctoides group on the other.     

Characteristics of the social life of bonnet macaques (Macaca radiata)

The social behavior of wild bonnet macaques impresses upon us a peculiality and uniqueness which is different from other macaques. Although there is a clear-cut ranking relationship among adult males and they carry out their proper social roles according to each situation, many social behaviors are carried out independently of or ignoring the ranking order. The animals are organized in a flexible and tolerant social unit, but they don't abandon the advantages of group life.The uniqueness of bonnet behavior and society is recognized to be related to the highly developed individuality of this species.     

Outcast males and social structure among bonnet macaques (Macaca radiata)

Outcast males are a regular feature of rhesus (Macaca mulatta) and Japanese (M. fuscata) macaque societies but are rare among bonnet macaques (M. radiata). Apparently bonnets have other solutions than ostracism for their social problems. For example, in many troops the male-female ratio ranges from 0.7?1.0+; and, as the young adult males grow to full social and physical maturity, they remain in the troop and participate actively in social relationships. A few troops of bonnet macaques, however, have a network of social relationships which prevents the young males from being integrated into the social system; in some of these cases, male isolation occurs. A comparison of the social relations between males in bonnet macaque societies of both types suggests that societies with strong male-male bonds accommodate their growing males better than those with highly individual males.     

Hematological and serum biochemical indices in healthy bonnet macaques (Macaca radiata)

Background Blood reference values for bonnet macaques (Macaca radiata) are limited. The goal of this study was to determine reference ranges for hematological and serum biochemical indices in healthy, socially housed bonnet macaques for males and females over a range of ages. Methods Blood hematological and serum biochemical values were obtained from 50 healthy bonnet macaques of both sexes and aged 10–234 months. Results Age and sex differences were present in a number of measures. Globulins, total protein, and creatinine (CREAT) values were highest among older subjects, while alkaline phophatase, albumin, and phosphorus values were higher in juveniles. Sex differences were present in concentrations of red blood cells and CREAT, with higher values in males. Conclusion The blood parameter data reported here as age‐specific reference values for laboratory‐housed, healthy bonnet macaques may be used to inform clinical care and laboratory primate research.     

Dominance and the social behavior of adult female bonnet macaques (Macaca radiata)

Female bonnet macaques are ranked according to naturally occurring dyadic aggressive interactions. Several possible correlates of these ranks are examined. Maternal rank and early life history are found to be highly correlated with rank. In addition, a number of social relationships (female/female presentations, female/female mounts, contact among females and aggression) are found to be related to rank. The meaning of rank outside of head to head encounters is discussed. This research was supported in part by the California Primate Research Center, University of California, Davis, Davis, California 95616.     

Social organization in captive barbary macaques (Macaca sylvana)

The hierarchy of a captive group of barbary macaques is compared with published accounts of the hierarchy of a wild-living group. Subordinate behaviours are correlated with rank in the captive group, but both dominant and subordinate behaviours are significant in the wild population. The relevance of this toRowell's views on hierarchies is discussed.     

Behavioral changes across the menstrual cycle in isosexual groups of bonnet macaques (Macaca radiata)

Behavioral changes were systematically recorded across menstrual cycles over a six-month period in two laboratory-housed isosexual triads ofMacaca radiata (bonnet macaque). The purpose of this study was to determine whether females of this species demonstrate premenstrual behavioral changes as reported for humans, or heightened levels of aggression during the first half of their cycle as reported in some species of Old World monkeys. A total of 34 menstrual cycles were divided into five segments including two follicular, one periovulatory, and two luteal phases. The mean frequencies of behaviors were analyzed according to phase, rank, and time since triad formation, for a total of 34 menstrual cycles. There was no evidence of an increase in spatial separation during the premenstrual phase or during any other phase of the menstrual cycle. Although contact aggression did not show an increase during the early follicular half of the cycle (phases 1 and 2) or during the phase of the cycle immediately preceding menses (phase 5), contact aggression did show two peaks: one in the early-mid luteal half of the cycle (phase 4) and a peak in the mid-late follicular (phase 2). The non-aggressive hierarchical behaviors did not follow the same pattern as contact aggression. Instead the distribution of these behaviors showed a pattern similar to that of estrogen levels across the cycle. Subjects’ location in pen also varied significantly according to cycle phase: subjects spent more time on perches during the premenstrual phase and more time on the pen floor during the periovulatory phase. The increase in contact aggressive behaviors during the early-mid follicular phase and the mid-late luteal phase does not suggest a simple hormonal correlate as these two phases are characterized by high levels of estrogen and progesterone, respectively. However, the distribution of non-aggressive hierarchical behaviors suggest that this category of agonistic interaction may be related to mating competition among females of this species. Results are discussed with reference to the social behavior and promiscuous mating strategy ofM. radiata. The findings in this present study are compared with previous studies utilizing other species of Old World monkeys. Differences in study design and group composition are considered as factors effecting discrepant results both within and between species.     

Strategies used by bonnet macaques (Macaca radiata) to reduce predation risk while sleeping

Sleep results in a decrease in alertness, which increases an animal’s vulnerability to predation. Therefore, choice of sleeping sites would be predicted to incorporate predator-avoidance strategies. The current study, conducted in two national parks in southern India, examined the behaviors adopted by bonnet macaques (Macaca radiata) to reduce the risk of being preyed upon while sleeping. Bonnet macaques from an urban setting with a low predatory risk were included for comparison. The physical characteristics of the sleeping sites in the forest corresponded with features that were most difficult for predators to access; bonnet macaques selected emergent trees with high boles near human settlements. These trees typically overhung water. Within the canopy, individuals slept in huddled subgroups near the terminal ends of branches, preferentially selecting branches over water. Subgroups were generally composed of members of the same age and sex, which likely promoted social bonding. Adult males and females with infants selected branches higher than members of other age and sex categories. The lateral distances of individuals along branches from the main trunk were similar across demographic categories. The size of a subgroup appeared to be limited by the weight a branch could support; lateral distances were maintained by regulation of mean subgroup weight, with heavier individuals forming smaller subgroups. The urban troop slept on the top of a building. Subgroup compositions at the urban site were similar to those at the forest sites. However, subgroup size, not restricted by branch fragility, resulted in larger subgroups than those found in the forest. Our results indicate that bonnet macaques adopted a suite of behaviors that reduced their risk of being preyed upon at night by selecting sleeping sites that minimized predator encounters and by selecting the safest locations within the canopy.     

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.     

Nasal cavity carcinosarcoma in a bonnet macaque (Macaca radiata)

An example of a rare, highly aggressive malignant intranasal neoplasm in a male Bonnet macaque is presented. The tumor invaded the bony orbit, distorted the position of the globe, and metastasized to regional lymph nodes and lungs. Histologically the tumor was composed of both mesenchymal and epithelial components and probably was of minor salivary gland origin.     

Malignant fibrous histiocytoma in a bonnet macaque (Macaca radiata)

Spontaneous sarcomas, not associated with an underlying disease, appear to be relatively rare in nonhuman primates. Since 1970, there have been few reported cases of naturally-occurring sarcomas of any kind in these species. A malignant histiocytoma and malignant fibrous histiocytoma have been described in a rhesus macaque and baboon, respectively. A malignant fibrous histiocytoma is defined as a sarcoma of varied pattern consisting of a mixture of histiocytic and fibroblastic elements. It is thought that the two cells types arise from a common precursor or that the fibroblastic elements are derived from the histiocytes. These tumors are relatively common in humans. Here we report a case of spontaneously-occurring malignant fibrous histiocytoma in an adult bonnet macaque.     

Blood groups of bonnet macaques (Macaca radiata), with a brief introduction to seroprimatology

The human-type A-B-O blood groups of 52 bonnet macaques (Macaca radiata) were determined. Application of method of population genetics indicated the gene frequences to be O = 0.173, A = 0.480 and B = 0.347. Cross testing of sera and red cells of the bonnet macaques revealed two blood-type-specific isoagglutinins, one of them strong enough for use as a blood typing reagent. No blood group polymorphism was revealed by testing bonnet macaque red cells with isoantisera produced in rhesus monkeys (M. mulatta) and in crab-eating macaques (M. fascicularis). The rhesus and crab-eating macaque isoantisera reacted either with all or with none of the bonnet macaque red cells tested.     

Manipulation of objects in a captive group of lion-tailed macaques (Macaca silenus)

The purpose of this study was to investigate the manipulative propensities of a captive group of lion-tailed macaques (Macaca silenus). Simple natural objects (browse and bamboo poles) were provided regularly in the home cage. Findings indicate richness in the frequency and form of manipulative activities, with juvenile males manipulating the test objects more frequently and exhibiting more goal-directed manipulative activity than adult females. A variety of goal-directed manipulative activities (use of objects to act as ladders, to apply leverage, and to create perches) occurred spontaneously, with some instances involving joint action or social use. These data are consistent with the hypotheses that macaques possess extensive capacities for object exploration and social facilitation, and that an evolutionary history of omnivorous foraging habits correlates positively with the expression of anomalous sensorimotor skills.     

Geophagy by the bonnet macaques (Macaca radiata) of southern India: A preliminary analysis

Bonnet macaques (Macaca radiata) in the Marakkanam Reserved Forest of southern India consume termitaria soils. Samples from the ingested termite mounds are compared with samples taken from the surrounding uneaten soils in an attempt to determine why the termitaria soils are eaten. Particle size, clay and primary mineral composition, geochemistry, and scanning electron microscopic analyses are used to search for a possible explanation for geophagy among the bonnet macaques. Kaolin minerals abound throughout the Marakkanam soil sample suite. But the termitaria soils are distinguished by the presence of small amounts of smectite. An abundance of kaolin minerals in combination with small amounts of smectite strongly resembles the mineralogy ofeko, a traditional African remedy for stomach ailments, and Kaopectate™, a western anti-diarrhoeal preparation. The percentage of mature leaves and fruits ofAzadirachta indica consumed by the bonnet macaques is relatively high. Plant feeding deterrents, such as, acid detergent fibre (ADF) and the inherent nature of the fruits ofAzadirachta indica, when consumed in large quantities to act as a purgative, could cause gastrointestinal upsets and diarrhoea. At Marakkanam, bonnet macaques ingest termitaria earth that would act as a pharmaceutical agent to alleviate gastrointestinal upsets and control diarrhoea.     

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.     

Response to social challenge in young bonnet (Macaca radiata) and pigtail (Macaca nemestrina) macaques is related to early maternal experiences

Previous experience affects how young primates respond to challenging social situations. The present retrospective study looked at one aspect of early experience, the quality of the mother-infant relationship, to determine its relationship to young bonnet and pigtail macaques' responses to two social challenges: temporary maternal separation at 5-6 months and permanent transfer to an unfamiliar peer group at 16-17 months. Relationship quality was measured quantitatively on 30 macaque mother-infant pairs with the Relationship Quality Index (RQI), the ratio of relative affiliation to relative agonism as previously applied to capuchin monkeys. Infants with high RQI values had amicable mother-infant relationships and infants with low RQI values had agonistic mother-infant relationships. Young monkeys with amicable and agonistic relationships showed consistent differences in behavior before, during, and after each social challenge, supporting the hypothesis that juveniles from amicable mother-infant relationships based on the RQI coped more effectively with social challenges than did juveniles from agonistic mother-infant relationships. Results suggest 1) characteristic amicability or agonism in early mother-offspring macaque relationships has the potential to influence offspring behavior in tense social contexts and 2) the RQI is useful as one of a coordinated suite of methods for studying the development of social skills.