Group-housing subadult male cynomolgus macaques in a pharmaceutical environment

The authors describe the preliminary results of a program to group-house male cynomolgus monkeys. Using a unique cage design, they were able to achieve environmental enhancement and enrichment that led to easier handling of the animals used in protocols for pharmacological research.     

Structure-guided foraging in long-tailed macaques

The aim of this study was to identify some of the cues that macaques follow when they search for new food sites. A social group of 37 long-tailed macaques was confined to a holding cage while an experimenter concealed food in an outdoor enclosure according to one of the following rules: (1) along the edge of a visible environmental border, (2) within structures of the same general type, or (3) along an ecologically irrelevant, invisible straight line. To provide the animals with a cue for detecting the rule, three piles of visible food were also presented according to the rule. Each of the 60 trials involved a different location in the 880 m² enclosure. The animals showed clear evidence of utilizing the first two rules from the outset of testing and the third rule about five trials. The animals found concealed food along environmental borders and within matching objects more quickly than along invisible lines. They also showed a rapid improvement in food finding on the invisible line. The results suggest that long-tailed macaques extend their search for food to a given class of environmental structure rather than exclusively by pure spatial gradients. © 1996 Wiley-Liss, Inc.     

Capturing wild long-tailed macaques (Macaca fascicularis).

Long-tailed macaques (Macaca fascicularis Raffles, 1821) were captured at various locations in the north of Sumatra as part of a study on social behaviour and genetic relationships. We used individual cage traps, a group trap, a blowpipe and an air-pressure rifle. Provided that the monkeys were willing to take bait, individual cage traps proved most successful; they gave a high capture rate with minimal disturbance of the group. Success with young juveniles and peripheral animals could be improved by placing elevated traps in the centre and in clusters at the periphery of the trapping site. Trapping had no clear lasting effect on the natural behaviour of the animals.     

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.     

Conflict,displacement activities,and menstrual cycle in long-tailed macaques

This study was aimed at testing whether the female menstrual cycle is associated with changes in social tension experienced by eight heterosexual pairs of long-tailed macaques (Macaca fascicularis). Displacement activities were considered as a behavioral measure of social tension and recorded during the periovulatory and the menstrual flow phases of the cycle. While male yawning and body shake underwent nonsignificant increases, male autogrooming and scratching increased significantly during the periovulatory phase. Female displacement activities did not show any significant difference between the two phases. Male and female socio-sexual behavior was not affected by the menstrual cycle. These results suggest that the male conflictual state, but not the female one, is affected by female menstrual cycle.     

Partial colectomy for treating acquired megacolon in long-tailed macaques.

A syndrome presenting as gross abdominal distension and diagnosed as acquired megacolon was observed in five adult female long-tailed macaques. Gastrointestinal signs included diarrhea, mucus in the stool, anorexia, and failure to pass stool, with repeated episodes of extreme abdominal distension and accumulation of gas and feces in greatly enlarged colons. Medical management was unsuccessful. A partial colectomy with a standard end-to-end colonic anastomosis was performed to remove the section of distended colon in each animal. Histologically, affected colons had degeneration and fibrosis, primarily in the longitudinal layer of the lamina muscularis. Hemograms, serum chemistries, and histopathologic features were not diagnostic of a specific etiology for megacolon. Four of five animals had undergone at least one obstetrical surgery. Two of these had the first episode of colonic distension within 3 days postoperatively. Intra-abdominal adhesions were noted during exploratory surgery in all animals. Three of five had colonic volvulus observed during colectomy. Recovery post-colectomy was uneventful and animals remained free of clinical signs of megacolon.     

Social influences on grooming site preferences among captive long-tailed macaques

Data on grooming in a colony of 38 captive Macaca fascicularis were collected over a period of 6 months. The goal was to investigate how five social parameters (age, kinship, sex, grooming frequency, and relative rank) influenced the choice of body part being groomed. Age and kinship did not have systematic effects of grooming site preferences. The sex composition of individual dyads and the frequency at which grooming occurred were the factors with the greatest effect on body sites groomed among adults. Relative to other dyad types, male-male dyads almost never groomed on the face, avoided the front side of the trunk, and preferred the tail and back. Dyads that groomed relatively infrequently also favored the tail and avoided the face, chest, and belly. Relative rank had an effect on the body sites groomed among adult females: a groomer ranking lower than her partner groomed more often on the face, chest, and belly than a groomer ranking higher than her partner. Several hypotheses are discussed in the context of these results. The only one that explains most of the major results is that recipients of grooming expose relatively invulnerable parts of their bodies (i.e., back and tail) to and avoid eye contact with groomers that are relatively dangerous.     

Breeding seasonality among long-tailed macaques,Macaca fascicularis,in Peninsular Malaysia

The females among more than 7000 long-tailed macaques, Macaca fascicularis,that had recently been trapped for biomedical research were examined for pregnancy. The animals were taken from the wild in the north of Peninsular Malaysia during the period 1978 to 1979 and in the south from 1978 to 1982. Both samples showed some pregnancies in all months of the year and a peak during the months of May to July. Additional peaks in other months in some years showed that, while the midyear pregnancy peak was significant, it was not as marked a phenomenon as is the breeding peak in many other species. This might be due to the complexity and unpredictability of both the climate and the macaques’ food supply in Peninsular Malaysia. The additional peaks also illustrated the pitfalls of generalizing about breeding seasonality on the basis of small samples.     

Positional behavior of long-tailed macaques (Macaca fascicularis) in northern Sumatra

Although the majority of extant primates are described as "quadrupedal," there is little information available from natural habitats on the locomotor and postural behavior of arboreal primate quadrupeds that are not specialized for leaping. To clarify varieties of quadrupedal movement, a quantitative field study of the positional behavior of a highly arboreal cercopithecine, Macaca fascicularis, was conducted in northern Sumatra. At least 70% of locomotion in travel, foraging, and feeding was movement along continuous substrates by quadrupedalism and vertical climbing. Another 14-25% of locomotion was across substrates by pronograde clambering and vertical clambering. The highest frequency of clambering occurred in foraging for insects, and on the average smaller substrates were used in clambering than during quadrupedal movement. All postural behavior during foraging and feeding was above-substrate, largely sitting. Locomotion across substrates requires grasping branches of diverse orientations, sometimes displaced away from the animal's body. The relatively low frequency of across-substrate locomotion appears consistent with published analyses of cercopithecoid postcranial morphology, indicating specialization for stability of limb joints and use of limbs in parasagittal movements, but confirmation of this association awaits interspecific comparisons that make the distinction between along- and across-substrate forms of locomotion. It is suggested that pronograde clambering as defined in this study was likely a positional mode of considerable importance in the repertoire of Proconsul africanus and is a plausible early stage in the evolution of later hominoid morphology and locomotor behavior.     

Survey of the long-tailed macaques introduced onto Tinjil Island,Indonesia

From February 1988 though June 1990, 475 adult long-tailed macaques (Macaca fascicularis) were released on Tinjil Island to establish a breeding program that will provide monkeys for biomedical research while contributing to Indonesia's primate conservation efforts. A survey was conducted during the summer of 1990 to assess the status of the island's population. Basic demographic data were consistent with those from other field studies of long-tailed macaques, and estimates of reproductivity suggest a successful breeding program. The facility established on Tinjil Island should serve as a useful model for future primate resource and conservation programs. © 1993 Wiley-Liss, Inc.     

Status of the long-tailed macaque Macaca fascicularis in Singapore and implications for management

The long-tailed macaque (Macaca fascicularis) population of the island-state of Singapore consists of ca. 1,218–1,454 individuals. About seventy percent of the population (ca. 1,027 individuals) is concentrated in both Bukit Timah and Central Catchment Nature Reserves, a system of reservoirs and forest reserves located in the center of Singapore. This core population resides mainly along perimeter forest areas of the reserve system, which is bordered by residential and recreational areas (e.g., parks and golf courses) and encircled by expressways. Periphery sub-populations (ca. 427 individuals) persist in forest fragments throughout Singapore mainland and on 5 offshore islands. Much of the Singaporean macaque population overlaps with human settlement and these commensal groups are mainly distributed close to roads, parks and residential areas. At least 70% of these groups are habituated to human presence and at least 50% to food provisioning. Moreover, commensal groups have more individuals and have higher infant:adult female ratios than non-commensal groups. The close association of habituated macaque groups living in human environments has led to increasing human-macaque conflict in Singapore. The overlap is also associated with human-induced population loss resulting from road accidents (2.4%); and trapping efforts (14%) aimed at ameliorating conflict issues. Consequently, it is important to better understand how humans are affecting macaque populations. In order to mitigate human-macaque conflict and at the same maintain a sustainable macaque population in Singapore, there is an urgent need for wildlife management strategies aimed at minimizing the extent of human–macaque conflict. Such strategies should include designing appropriate buffers around reserve areas, revised urban development plans, and managing the behavior of people interfacing with macaques.     

Small-scale variability in a mosaic tropical rainforest influences habitat use of long-tailed macaques

Pristine habitats have generally been considered to be the most important ecological resource for wildlife conservation, but due to forest degradation caused by human activities, mosaics of secondary forests have become increasingly prominent. We studied three forest types in a mosaic tropical forest consisting of short secondary forest (SS), tall secondary forest (TS) and freshwater swamp forest (SF). These forests differed in stand structure and floristic composition, as well as phenological productivity of fruits, flowers and young leaves. We examined habitat use of long-tailed macaques (Macaca fascicularis) in relation to indices of phenological activity. The macaques used the SS for feeding/foraging more than the TS and the SF. This was because the SS had higher productivity of fruit, which is a preferred food resource for macaques. Stem densities of young leaves in the SS and the TS also influenced habitat use, as they provided more clumped resources. Use of SF was limited, but these forests provided more species-rich resources. Our results showed that M. fascicularis responded to small-scale variability in phenological activity between forest types found in a heterogeneous mosaic forest, with young secondary regrowth forests likely providing the most important food resources. Mosaic landscapes may be important as they can buffer the effects of temporal food resource variability in any given forest type. In our increasingly human-altered landscapes, a better understanding of the role of secondary forest mosaics is crucial to the conservation and management of wildlife habitats and the animals they support.     

Functional aspects of reconciliation among captive long-tailed macaques (Macaca fascicularis)

After an agonistic conflict between two animals, they may exchange affiliative social contacts. The function of this reconciliation behavior is thought to be the repair of the social relationship between the two opponents. We examined the hypothesis that reconciliation is socially effective because it may also lead to a reduction of the victim's acute stress. Reconciliation was studied in a well-established captive group of long-tailed macaques (Macaca fascicularis). The behavior of the victim in a 10 min period after the end of an agonistic interaction was recorded and compared with that of a control observation made on the same animal the next day. The tendency to reconcile was elevated above control levels only during the first 3 min. Reconciliation led to a fast reduction in scratching rates and to a decrease of the reoccurrence of aggression received. Losers took the initiative to reconcile more than expected. Dominants granted reconciliation depending on their relatedness with the victims and on the quality of the relationship with them. After those interactions in which contra-aggression and no clear submission occurred, the reconciliation rate was remarkably high. These results suggest that reconciliation can be an effective means to reduce the victim's acute stress and that its function in repairing social relationships can partly be mediated by its physiological effects. The intimate relation between the quality of the social relationship and the conciliatory tendency can be extrapolated to explain interspecific variation.     

Alternative seed-handling strategies in primates: seed-spitting by long-tailed macaques (Macaca fascicularis)

Summary The seeds in fruits consumed by primates may be chewed and digested, swallowed and defecated intact, or separated from the flesh and spat out. We show by a combination of close field observations and experiments with caged animals, that long-tailed macaques (Macaca fascicularis) have a remarkably low threshold of 3–4 mm for swallowing seeds and also that wild macaques rarely break them. The seeds of 69% of the ripe fruit species eaten are spat out intact or cleaned outside the mouth and dropped. Seed-spitting significantly reduces the swallowed food bulk and may lessen the risk of releasing seed toxins during mastication. However, it requires that even small fruits are processed in the mouth one or a few at a time. We suggest that fruit storage in the cheek pouches of cercopithecine monkeys allows them to spit seeds individually without excessively slowing fruit intake while feeding on patchily distributed fruit. In contrast, Apes and New World monkeys apparently swallow and defecate most ripe seeds in their diet and colobine monkeys break and digest them, detoxifying seed defenses by bacterial fermentation.     

Testing kin altruism in long-tailed macaques (Macaca fascicularis) in a food-sharing experiment

Social grooming and coalition formation have been main foci in studies concerning altruism in monkeys. Results have been inconclusive because the altruistic nature of these behaviors remains unclear. I investigated altruism in a more transparent context via an apparatus in which captive long-tailed macaque females had the choice to exploit a food source themselves or to yield the food to a test partner. I hypothesized that if potential donors behaved altruistically toward kin, they would yield the food sources longer to kin than to nonkin. Of 11 tested potential donors, 8 did not discriminate between daughters or sisters and nonkin. Thus, the experiments do not support the kin altruism hypothesis. Three females let their youngest offspring have more food than matched juvenile nonrelatives. Behavioral observations strongly suggested,however, that it was primarily spiteful behavior toward juvenile nonrelatives that caused the differences between kin and nonkin in these three cases.     

Relatedness of matrilines,dispersing males and social groups in long-tailed macaques (Macaca fascicularis).

Genealogical relatedness is thought to be an important causal factor in the evolution of cooperation. We inferred relatedness on the basis of 11 blood protein markers using the Queller and Goodnight index of relatedness in a macaque population with long-term demographic records. This estimate reflected independently determined pedigree relationships in our data set. Mean relatedness among all members of a social group was 0.10 but much higher levels of relatedness (0.30-0.47) were found among the members of matrilineal families with a high or intermediate social rank. Groups of dispersing males that had been born into the same social group were sometimes closely related (0.43 and 0.58), but they could also be less related (0.08). We found that the pattern of distribution of relatedness was associated with gene flow and differential reproduction in males, rather than with group fission and the presence of geographical barriers.     

Genetic characterization of long-tailed macaques (Macaca fascicularis) on Tabuan Island Indonesia

Protein and mitochondrial DNA variations (D-loop region PCR-RFLP) were analyzed for 7 serum and 40 clot samples collected from long-tailed macaques (Macaca fascicularis) living on Tabuan Island, Indonesia. Protein polymorphisms were examined electrophoretically for 5 and 12 kinds of protein in serum and erythrocytes, respectively. Each of the protein loci tested showed a monomorphic pattern. Polymorphisms were detected in the analysis of the D-loop-containing region of mtDNA (PCR-RFLP) using 32 restriction endonucleases. Two haplotypes, differing 1.03% in sequence divergence were observed, and both were previously undetected in other local populations. Based on genetic features and differences in pelage color as outlined inFooden's (1995) morphological analysis, the present results suggest that long-tailed macaques on Tabuan Island are a unique population. From the genetic analyses performed here, Tabuan monkeys are considered to be the same species group as those populations of Sumatra and Java (Fooden, 1995).     

The human-ABO blood groups of free-ranging long-tailed macaques (Macaca fascicularis) and parapatric rhesus macaques (M. mulatta) in Thailand

BACKGROUND: Long-tailed and rhesus macaques are widely used in biomedical research; therefore, the known blood group is important. METHODS: The human-type ABO blood group was determined in wild or semi-wild long-tailed and rhesus macaques in Thailand. A total of 729 long-tailed and 160 rhesus macaques from 20 localities were temporarily caught. RESULTS: The frequency profiles of blood groups, calculated by averaging the frequency of each troop in long-tailed and rhesus macaques, were AB > O > B > A at 29.6%, 27.4%, 27.2%, and 15.8%, and B > AB > A > O at 39.6%, 33.4%, 18.2%, and 8.8%, respectively. Irrespective of locality, the frequencies were AB > O > B > A of 29.6%, 28.0%, 24.4%, and 18.0%, and AB > B > A > O of 37.5%, 28.7%, 26.9%, and 6.9%, respectively, for all long-tailed and rhesus macaques. The frequency profile of blood groups in Thai rhesus macaques was somewhat similar to that in the parapatric long-tailed macaques; however, it was different from other rhesus populations where only group B was detected. CONCLUSIONS: Our data support the hypothesis that Indochinese rhesus macaques are hybrids between rhesus and long-tailed macaques in the past.     

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.     

Agonistic encounters and brain activation in dominant and subordinate male greater long-tailed hamsters

During an agonistic encounter test, dominant male greater long-tailed hamsters (Tscheskia triton) initiated attacks sooner and displayed higher levels of aggression and flank marking behavior than their subordinate counterparts. Accordingly, subordinate males exhibited more defensive behavior than dominant ones. Specific patterns of neuronal activation, measured by Fos-immunoreactive staining (Fos-ir), were found in the hamster brain following agonistic interactions. Increased Fos-ir was observed in the bed nucleus of the stria terminalis (BST), ventromedial hypothalamus (VMH), and medial (MeA) and anterior cortical (ACo) nuclei of the amygdala (AMYG) in both dominant and subordinate males. In contrast, dominant males had significantly higher Fos-ir densities in the medial preoptic area (MPOA) than subordinate males, whereas subordinate males expressed higher densities of Fos-ir in the anterior hypothalamus (AH) and central nucleus of the amygdala (CeA). Additionally, Fos-ir levels in the MPOA were significantly correlated with aggression and Fos-ir levels in the AH and CeA were correlated with defensive behavior. Together, our data indicate distinct patterns of neuronal activation associated with agonistic encounters in a behavior-specific manner in male greater long-tailed hamsters.