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.     

Some reproductive parameters of stumptailed macaques (Macaca arctoides)

Reproductive records kept from 1969 to 1981 were used to study menstrual cycles, pregnancies and births of eight colony-housed stumptailed macaques. The findings for annual distribution of births, pregnancy duration and infant sex ratio were consistent with previous reports. The interbirth interval after infant loss was significantly shortened from the interbirth interval when infants were maintained with their mothers. Vaginal bleeding during early lactation indicates that stumptails are not necessarily characterized by a prolonged period of postpartum amenorrhea. Complete copulation was observed prior to six months postpartum, but interbirth intervals indicate that conception did not occur prior to that time. Interbirth intervals tended to be shorter for dominant than for subordinate females and to lengthen as a function of increasing age.     

Responses to animal stimulus photographs in stumptailed macaques (Macaca arctoides)

Interest in their animate environment was studied in a captive group of 11 stumptailed macaques (Macaca arctoides). Subjects were shown projected photographic slides, most of which showed a single individual primate or non-primate. The measure of interest was the duration of viewing. Results showed that adult females exhibited more interest towards stumptailed macaques versus other macaques species, and towards adult females carrying infants versus adult females alone. Data concerning non-primates showed that subjects were especially interested by photographs of felids; this effect was partly due to the presence of two frontal and conspicuous eyes in felids.     

The effects of temporary cover on the behavior of socially housed stumptailed macaques (Macaca arctoides)

To examine the effects of the provision of temporary cover on the behavior of stumptailed macaques (Macaca arctoides), a single group of 26 animals was observed during 25 testing periods over 7.5 months. During each testing period, the group was observed under two conditions. In the Cover condition, two solid temporary walls 9.6 m in length, were erected within the animals' living compound. In the No-Cover condition, the wall materials were stacked against one solid exterior wall of the compound. The provision of cover significantly reduced the levels of contact aggression, proximity between animals, and locomotion, and reduced the ability of the dominant male to monopolize copulations. It did not effect other measures of affiliation. Inconsistencies between these results and those of other published studies suggest that, while cover can have a significant influence on some kinds of social behavior in some situations, generalizations about the benefits of providing cover to captive animals may be premature.     

The structure of affiliative relations in a primate community: Allogrooming in stumptailed macaques (Macaca arctoides)

Social grooming in 19 adult stumptailed macaques (a dominant male and 18 females) was studied by focal sampling and scanning methods. Significant individual differences were found with respect to both active and passive grooming intensity, active grooming being a more variable parameter. Individual preferences in partner choice are very strong, but among the factors examined, age was the only one influencing these preferences. Neither social rank nor kinship were significant. The proportion of active and passive contacts shows marked individual differences. Yet, there is a positive association between performed and received grooming. The “extortion hypothesis” is not supported by our results: high-ranking individuals performed on the average more, and received relatively less grooming than low-ranking ones. High grooming performance of the dominants may secure group integrity in species with a “soft” dominance style.     

Placenta extrachorialis in the stumptailed macaque (Macaca arctoides).

Placenta extrachorialis was diagnosed in two of 56 placentas obtained from stumtailed macaques (Macaca arctoides) after elective cesarean section. The condition was characterized by the presence of an annular ring of necrotic tissue and fibrin at the margin of the villous chorion. Because these cases occurred in two of six known primiparous females, it was suggested that thte condition may account, at least in part, for the high incidence of pregnancy-related problems observed in primiparous stumptailed macaques.     

Video-induced yawning in stumptail macaques (Macaca arctoides)

This study reports the first experimental exploration of possible contagious yawning in monkeys. Twenty-two stumptail macaques (Macaca arctoides) were presented with video clips of either yawns or control mouth movements by conspecifics. At a group level, monkeys yawned significantly more often during and just after the yawn tape than the control tape. Supplementary analysis revealed that the yawn tape also elicited significantly more self-directed scratching responses than the control tape, which suggests that yawning might have been caused by tension arising from viewing the yawn tape. Understanding to what extent the observed effect resembles contagious yawning as found in humans and chimpanzees requires more detailed experimentation.     

Venipuncture and vaginal swabbing in an enclosure occupied by a mixed-sex group of stumptailed macaques (Macaca arctoides)

Procedures are described for vaginal swabbing and venipuncture in a gang-caged, mixed-sex group of stumptailed macaques. The design of the gang cages facilitated venipuncture and swabbing which were done without undue disturbance of the vivarium routine, without seriously stressing colony members, and without interfering with the monkeys' established social relationships.     

Surgical correction of eyelid disfigurement in a stumptailed monkey (Macaca arctoides)

Self-aggression in an adult male stumptailed monkey (Macaca arctoides) resulted in severe lower eyelid distortion, conjunctivitis and epiphora. The behavior ceased with a change in environment, but the eyelid defect, conjunctivitis and epiphora persisted, requiring corrective surgery. Surgical correction was partially successful, although the animal died due to unrelated medical problems before final correction could be accomplished.     

Non-seasonal breeding pattterns in stumptail macaques (Macaca arctoides)

This paper summarizes published reports of breeding patterns across the genusMacaca. Patterns range from strictly seasonal to non-seasonal. Data on sexual behavior and birth patterns are presented which confirm previous reports of non-seasonality forMacaca arctoides. In a captive colony, 63 births were recorded, and individuals were born during every month of the year. Heterosexual mounting activity was recorded over a two-year period and occurred during every month of that period. It is clear thatM. arctoides does not exhibit the seasonal cyclicity observed in some other macaque species.     

Endocrine changes in male stumptailed macaques (Macaca arctoides) as a response to odor stimulation with vaginal secretions

In mammalian species, social chemosignals are important in modulating endocrine reproductive functions. In nonhuman primates, previous studies have described a high frequency of mounting behavior by females in the follicular and periovulatory phases of the menstrual cycle. Stumptailed macaque females do not signal receptivity by means of sexual swellings, as do others macaques, therefore providing a good model in which to study chemical signaling of reproductive status. We exposed anesthetized stumptailed males to vaginal secretions of either late follicular or menses phase or to saline solution to determine the endocrine changes promoting male sexual behavior. In males exposed to follicular secretions, plasma testosterone concentrations were sustained up to 120 min after exposure. Such an effect was not observed in animals exposed to menses or saline odor sources. A luteinizing hormone surge, occurring 30 minutes after exposure to late follicular phase secretion swabs, preceded this sustained testosterone effect. The fact that late follicular scents induce sustained testosterone concentrations provides support to the idea that stumptailed males draw information concerning female reproductive status from the female's vaginal odor.     

Changes in the social structure of two groups of stumptail macaques (Macaca arctoides)

Two previously studied groups of stumptail macaques were restudied to investigate stabilities and instabilities within group structures. Frequency data for nonsocial and dyad behaviors were collected. While there was considerable group stability, several important changes occurred. The most noteworthy group changes were in grooming and playing. Individual changes centered upon females. The first and fourth ranking females of one group switched dominance positions. The roots of this reversal were minimally reflected by aggressive and submissive interactions, and more fully exposed by quiet association patterns such as grooming, huddling, and sitting together. Increased frequencies of huddling, touching, and approaching indicated that the lowest ranking female of each group moved closer to other group members. There was no hint of this change in agonistic interactions.     

Female-infant interactions among free-ranging stumptail macaques (Macaca arctoides)

The friendly and aggressive behaviors directed by females other than the mother to the troop's infants were recorded during a six-month long study of stumptail macaques living on an island. A great deal of friendly contacts were directed by the females toward the troop's infants. Juvenile females interacted with infants mainly through social play while adult females directed passive contacts (e.g., touch-hand) to them. While the adult females displayed more care contacts toward male infants the juvenile females preferred the female infants. The social position of the infant's mother in the troop and the attention it received from the males regulated the caring behavior an infant received from the females.     

Environmental enrichment for captive stumptail macaques (Macaca arctoides)

Background  The behavior of animals is modified by captivity. Environmental enrichment (EE) is a program designed to enhance the welfare of confined animals by providing them with a more stimulating background. This is carried out by the implementation of a series of activities that encourages them to present behaviors typical of their species, as well as keeps them active. The aim of this study was the evaluation of the influence of the EE in the behavioral variables in a colony of 24 stumptail macaques ( Macaca arctoides ). Our hypothesis is that the application of this program will reduce aggression, stereotypes and coprophilia behaviors and, at the same time, will increase exploration and solitary play.
Methods  The behavioral frequency previous to EE was compared with that during EE implementation.
Results  Our results showed that aggression, coprophilia stereotypic behaviors and social play were significantly reduced during EE, whereas exploration was significantly enhanced. The response of the individuals according to gender was similar for both sexes.
Conclusions  Environmental enrichment programs are indispensable for captive animals' wellbeing as they reduce aggression and stress while providing animals both physical and cognitive entertainment.     

A twenty-one-year study of maternal dominance and secondary sex ratio in a colony group of stumptailed macaques (Macaca arctoides)

Trivers and Willard's theory of sex-ratio adjustment, as applied to cercopithecines, predicts that the ratio of male to female offspring will be greater for dominant than for subordinate mothers. A local-resourcexyhcompetition hypothesis predicts the reverse. To date, results from several species of macaque are inconsistent and often not statistically significant. In this 21 year study, a colony group of stumptailed macaques is added to the species previously studied. Seventy-five offspring were born to eight mothers for whom long-term dominance was established. Chi-square analyses of data from these 75 offspring failed to yield a significant relationship between sex-ratio and mother's dominance; consequently, consistent with a growing body of cercopithecine literature, neither of the competing theories was supported. © 1994 Wiley-Liss, Inc.     

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.