Seroprevalence of B virus (Herpesvirus simiae) antibodies in a naturally formed group of rhesus macaques

Eighty-two percent of a group of rhesus monkeys removed from Cayo Santiago were seropositive for B virus (Herpesvirus simiae) antibodies. Similar results were obtained from the Cayo Santiago macaque population two decades ago and from feral Indian rhesus monkeys. Thus it is likely that B virus has been enzootic in the Cayo Santiago population since 1938, when the colony was established with stock imported from India.     

The formation of relationships based on socio-spatial proximity in a free-ranging colony of rhesus monkeys

This study attempted to describe the pattern of social affiliations in a colony of free-ranging rhesus monkeys (Macaca mulatta) on Key Lois Island, Florida. Monkeys arrived to Key Lois in nine distinct groups that were held in a 50×100 ft enclosure for between 30 and 60 days and then released. The data consisted of observations of groups of monkeys seen together at various times in various locations. The study tested the hypothesis that monkeys that were in the same quarantine group would more frequently be seen together in the free-range than monkeys from different quarantine groups. The hypothesis was confirmed in seven of the nine groups. Chi-square =2137.1 (p<.001),Cohen’s kappa =.38 (p<.001) (1960). Prior common group membership was found to be predictive of future social affiliations. Explanations of residual kin structure from India, the effect of a primary social experience in a new environment, and the possibility of in-group versus out-group forces between the successively introduced groups were advanced as possible reasons for the findings.     

Species discrimination and concept formation by rhesus monkeys (Macaca mulatta)

There are 19 species in genusMacaca and some of them are living in sympatry (Fooden, 1980). Although inter-specific hybrids are relatively easy to produce under artificial conditions, hybridization does not occur naturally. What is preventing that among the species of genusMacaca? Three rhesus monkeys acquired a discrimination between pictures with rhesus monkeys and without rhesus monkeys. All subjects showed positive transfer of this discrimination to new pictures with rhesus monkeys and without rhesus monkeys. A further test showed that these monkeys could discriminate between pictures of rhesus monkeys and pictures of Japanese monkeys. The results suggest that rhesus monkeys recognize rhesus monkeys as a class, independent of the actual stimuli such as a picture or an individual monkey. The ability to recognize members of their own species and the opportunities for such learning may be an important factor preventing hybridization among the species of genusMacaca.     

Conservation note: Socioecology and conservation of macaques and langurs in Varanasi,India

A survey of rhesus monkeys (Macaca mulatta) and hanuman langurs (Presbytis entellus) was conducted in urban and forest areas of Varanasi, India. Data were collected on group size and composition. Nine groups of rhesus monkeys inhabited various urban niches, but langurs were completely absent from urban areas. Approximately 159 rhesus monkeys and 720 langurs lived in the forested area. Both the urban and the forested habitats of this area are being reduced in size, and it is suggested that these populations be moved to nearby forest preserves.     

Age of sexual maturity in laboratory-born pairs of rhesus monkeys (Macaca mulatta)

Two pairs of laboratory born rhesus monkeys gave birth to healthy young at an unusually early age, indicating that sexual maturity for this species is possible at a much earlier age than had been previously reported.Supported by MH22253 toG. Mitchell, HD04335 toL. Chapman, RR00169 to California Primate Research Center and MH54546-01 toTerry Maple.     

Long-term effects of social rehabilitation in rhesus monkeys

A group of 19 rhesus monkeys was assembled and observed in a large outdoor pen. Five experimental groups were present: 3-year-old mother-peer reared monkeys, surrogate-rehabilitated isolates, socially-rehabilitated isolates, surrogate-peers (who had served as “therapists” for the preceding group), and 1-year-old mother-peers. The major results indicated first, that the surrogate-rehabilitated isolates played socially significantly less than both mother-peer groups, and second, that the group as a whole seemed to display an abnormally low overall level of behavior. Possible interpretations and theoretical implications are discussed. Request reprints fromMark S. Cummins, Department of Psychology, McGill University, Montreal, Quebec, Canada.     

Phylogeny of rheusus monkeys (Macaca mulatta) as revealed by mitochondrial DNA restriction enzyme analysis

Mitochondrial DNA, purified from 36 samples of 23 local populations which are widely distributed in Vietnam, Burma, and 10 provinces of China, has been analyzed to model the phylogeny of rhesus monkeys. The 20 local populations of China may represent nearly all major populations in China. Using 20 restriction endonucleases of 6-bp recognition, we observed a total of 50–61 sites in the various samples. By combining the cleavage patterns for each enzyme, the 36 samples were classified into 23 restriction types, each of which was found exclusively in the respective population from which samples were obtained. By combining the earlier study of Indian rheusus monkeys, phylogenetic trees, which have been constructed on the basis of genetic distance, indicate that rhesus monkeys in China, Vietnam, India, and Burma can be divided into seven groups. Integrating morphological and geographical data, we suggest that rhesus monkeys in China, Vietnam, and Burma may be classified into six subspecies—M. m. mulatta, M. m. brevicaudus, M. m. lasiotis, M. m. littoralis, M. m. vestita, and M. m. tcheliensis-and rhesus monkeys in India may be another valid subspecies.M. m. tcheliensis is the most endangered subspecies in China. Divergence among subspecies may have begun 0.9–1.6 Ma. The radiation of rhesus monkeys in China may have spread from the southwest toward the east. The taxonomic status of the Hainan monkey and the Taiwan monkey require further investigation.     

Partial recovery and a new population estimate of rhesus monkey populations in India

The purpose of this field study has been to assess major changes in rhesus monkey populations of north central India over a period of 28 yrs from 1959 to 1986. Population censuses have been done in Aligarh District three times per year, and extensive regional surveys were done in 1959–1960, 1964–1965, 1977–1978, and 1985–1986. Throughout the 1960s and 1970s, rhesus populations in India declined more than 90%, from an estimated 2 million animals in 1960 to approximately 180,000 by 1980. These declines were attributed to increasing agricultural pressures in India, loss of primate habitats, less protection for monkeys, and high levels of trapping. In the 1970s, as India's agricultural production rose and stronger wildlife conservation programs developed, local populations of rhesus began to increase. These increases became more prominent after 1978, when India imposed a ban on export of monkeys. By 1985 a population in Aligarh District had returned to its 1960 level in total population size, although the number of groups remained low. Other local populations showed even more striking growth and greatly exceeded former levels. Some areas of India, however, have shown no improvement in rhesus populations. Overall, extensive field surveys of rural habitats in 1985–1986 showed a 53% recovery in the number of rhesus groups, and a 129% recovery in total rhesus from their low points in 1977–1978. We estimate the rhesus population of India in 1985 in the vicinity of 410,000–460,000 individuals.     

Interspecies dyadic attachment before and after group experience

Social behavior between representative members of different taxa has been observed in the field and studied in the laboratory. In the study described here, two female rhesus monkeys were paired with female baboons during infancy. Preference tests were conducted after interspecies pair-living, followed by one month of group experience and a subsequent preference test. The results indicated that each animal formed social attachments to the alien partner. Further studies of interspecies interactions should contribute to our understanding of behavioral isolation and the process of speciation. This research has been supported by grants from the United States Public Health Service: HD04335 to L.Chapman, and RR00169 to the California Primate Research Center. Additional funds were supplied by an intramural grant to G.Mitchell from the University of California.     

利用微卫星遗传标记对恒河猴进行遗传同质性分群的探索

目的探索建立利用微卫星遗传标记对中国恒河猴免疫遗传学同质性分群的方法。方法根据已报道的中国恒河猴和印度恒河猴微卫星标记和与MHC基因高度连锁的微卫星遗传标记,对52只恒河猴进行了微卫星检测和遗传同质性分群。结果依据判断标准,可以将检测的恒河猴分为印度恒河猴,中国恒河猴和无法判定来源的恒河猴3个地理类别,并根据MHC附近的微卫星遗传标记将其分为若干MHC基因相同的同质性群体。结论此方法的建立将有利于恒河猴参与的实验分组,也为恒河猴繁殖管理提供了参考。     

Evaluation of intra-blood brain barrier IgG synthesis rate and blood brain barrier function in normal rhesus monkeys

In order to evaluate blood brain barrier (BBB) integrity and intra-BBB IgG synthesis under CSF pathologic conditions, it is necessary to establish normal values in a control population. In this study an evaluation was made of the blood brain barrier (BBB) integrity and intra-BBB IgG synthesis in the central nervous system (CNS) of normal juvenile rhesus monkeys to establish these values. Parallel cisternal cerebral spinal fluid (CSF) and venous serum samples were collected from 12 healthy male rhesus monkeys. Normal values for CSF/serum ratios of IgG and of albumin were determined and incorporated in theTourtellotte formula for quantitation of intrathecally synthesized IgG per 24 hours. The effect of systemic mannitol administration on the BBB was also evaluated by the primate adapted formula and magnetic resonance imaging contrast enhanced studies.     

Mother-infant separation in rhesus monkey living in natural environment

Four mothers were separated from the infants in two free-ranging groups of rhesus monkeys. Infants were observed for three stages i.e. pre-separation, separation, and post-separation. Separation caused a marked decrease in play in the infant. Crying and restlessness increased. During post-separation, a significant increase in mother's approach behaviour towards the infant was observed. The results of the present field study almost resemble the results of laboratory studies done bySeay, Hansen, andHarlow (1962).     

Multiple testing for the detection of B virus antibody in specially handled rhesus monkeys after capture from virgin trapping grounds.

Eight groups of rhesus monkeys totaling over 1,000 animals were captured in the virgin trapping grounds of Jammu and Kashmir, India. Individual caging and special handling technics were utilized to prevent cross-contamination during capture, holding, and subsequent shipment to quarantine facilities in the United States. Immediately following the arrival of the monkeys, 5 consecutive blood samples were obtained at approximately 2-wk intervals, and the sera were rested for neutralizing antibody against Herpesvirus simiae. In order to assure the greatest sensitivity possible, sera were not heat-inactivated and were tested against only 10 TCID50 units of virus in addition to the more commonly used concentration of 100 TCID50 units. The first test detected 80-90% of the positive animals within each group, and only 1 seroconversion was noted after the second test. Seventy-three percent of the adults, 36.6% of the young adults, and 12.4% of the juvenile macaques were found to be antibody-positive. Considering the measures employed to prevent cross contamination, these percentages probably reflect the true prevalence of B virus infection in these rhesus monkeys at the time of their capture in the wild.     

Isolation of Campylobacter jejuni from experimental dogs and monkeys in Japan

Isolation of Campylobacter jejuni (C. jejuni) from experimental dogs and monkeys was undertaken. C. jejuni was detected from 14.7% of the fecal samples obtained from beagles in a production colony, whereas 32% of newly imported beagles harbored the organisms. C. jejuni was isolated from 25% of the young and 3.9% of adult dogs in an animal center. The organisms were isolated from newly imported cynomolgus and rhesus monkeys at high frequencies (49.2% and 38.8%, respectively). Almost all of the strains isolated were highly sensitive to erythromycin, chloramphenicol and gentamicin.     

A serological survey of simian virus 40 in monkeys

A serological survey of simian virus 40 (SV 40) was conducted by an immune adherence hemagglutination (IAHA) test in breeding monkeys. Of a total of 356 monkeys tested, 168 (47.2%) were seropositive. All 168 seropositive monkeys were detected from 224 monkeys which were bred or kept in Japan for a long time. In contrast, none of the 132 monkeys which were newly imported from Southeast Asia was seropositive. If a comparison was made in the same breeding place, the positive rate of 80.4% (111/138) of Japanese monkeys was significantly (P less than 0.01) higher than the 59.5% (25/42) among rhesus monkeys. The positive rate and the IAHA titers were higher in older age group (greater than 5 years) but similar in male and female. These results indicated that SV 40 was highly prevalent among breeding monkeys in Japan.     

Live birthrates in two free-ranging rhesus breeding colonies in the Florida keys

The present paper provides an analysis of reproductive data derived from 1,265 adult female rhesus monkeys (Macaca mulatta), including 570 animals 13 years old and older. The data were collected during a partial census of two provisioned but free-ranging rhesus populations in the Florida Keys. Within both colonies, live birthrates were found to increase sharply among females 4–7 years old and to decline linearly among females 7–17 years of age. These data do not support the suggestion byAnderson (1986) that decline in fertility among nonhuman primate females is primarily the result of deteriorating health rather than ageper se.     

Sexual differences in the ependyma lining the third ventricle in the area of the anterior hypothalamus of adult rhesus monkeys

Summary Previous studies have shown that a circumscribed region of the anterior hypothalamus of the rhesus monkey is lined by tanycyte ependyma and it has been suggested that this ependyma which links the third ventricle with the pars tuberalis may have a functional role in the hypothalamic regulation of anterior pituitary function (Anand Kumar and Knowles, 1967a). In view of the known sexual differences in the hypothalamic regulation of pituitary gonadotropin secretion the present investigation was made to determine whether any structural differences were evident in the tanycyte ependyma in male and female rhesus monkeys.The results of this investigation are based on light and electron microscopic studies of the hypothalamus in 24 rhesus monkeys comprising 12 adult females, 11 sexually mature males and a two month old sexually immature male.The tanycyte ependyma in the rhesus monkey is double layered. There are bulbous projections on the ventricular surface of the cells in the ependymal layer nearest to the ventricle (the first layer of ependyma). These bulbous projections vary in size in relation to the menstrual cycle. They are well developed during mid-cycle and regressed during menstruation. In the males, where the secretion of pituitary gonadotropins does not occur cyclically as in the females, there was no marked variation in the bulbous projections between different individuals as in the female monkeys.In the sexually mature males, but not in the females, the two layers of ependyma are separated by a distinct space. The absence of such a space in the sexually immature male suggests that this difference may be related to sexual maturity.In the adult males the cells in the ependymal layer below the first layer of ependyma have microvilli which extend into the space between the ependymal layers. In the females where such a space is not present, microvilli were not evident.The precise functional significance of the tanycyte ependyma is not known. It is hoped that the results of the present investigation would draw attention to the need for a more detailed examination of the physiological role of the tanycyte ependyma in relation to reproduction.The expenses for this investigation were met from a grant made by the Ford Foundation to Professor Sir Solly Zuckerman and the electron microscope was provided by the Medical Research Council. I am indebted to Sir Solly for his interest in this work.     

Effects of artificial feeding on aggressive behaviour of rhesus monkeys in India

Artificial feeding of rhesus monkeys (Macaca mulatta), which provides the major food source for most rhesus groups in rural and urban habitats, is common practice in India. Such feeding results in significant increases in aggressive competition within the monkey groups: during feeding periods the frequencies of aggressive threats, chases, and attacks increased two to six times above those of non-feeding periods in each of eight different groups. Fighting behaviour did not increase in most groups studied, but did show a rise in one large urban group in Calcutta. The implications of these results for the management of primate breeding colonies are discussed.     

Changes in the behavior of laboratory-reared rhesus monkeys following the threat of separation

Four heterosexual pairs of three-year-old rhesus monkeys were either repeatedly separated from each other for 30-min or not separated. Prior to each separation, a transfer cage was displayed at the front of the cage to serve as a cue that the pair would be separated. After only a few trials, the animals displayed disturbance, particularly in the form of stereotyped pacingprior to the separation. Practical considerations related to laboratory methodology, a theoretical discussion concerning the fear of separation in monkeys and man, and the need for attention to individual differences in response to separation were emphasized.Supported by NIH grants MH22253, HD04335, and RR00169, to Dr.Gary Mitchell; whose assistance is gratefully acknowledged.     

Estrous behavior of free-ranging rhesus monkeys (Macaca mulatta)

The sexual behavior of a group of free-ranging rhesus monkeys (Macaca mulatta) was studied for 13 consecutive months in an attempt to determine whether or not sexual activity occurred year-round, and the importance of sexual attraction to rhesus monkey social organization.Estrous behavior was seen both inter-menstrually and peri-menstrually, producing a shorter mean estrous cycle length than reported by other workers. New data was gathered on the interrelationships among age, dominance rank, and sexual activity; son-mother and brothersister matings; and sexual favoritism among free-ranging rhesus monkeys.A few females who failed to conceive during the fall breeding season showed cyclic estrous behavior throughout the entire annual cycle. Hypotheses are given as to possible physiological bases for birth season sexual cycles.Several forms of inter-animal bonding, including sexual bonding, are enumerated, and their importance to rhesus monkey social organization discussed.