Status and Conservation of Douc Langurs (Pygathrix nemaeus) in Laos

A recent systematic survey program of protected areas in Laos documented douc langurs (Pygathrix nemaeus) widely between 14°25N and 18°38N. Their precise northern limit is unclear as security constraints prevented survey there, but the species is unlikely to occur in Laos north of 20°. All our records are of the nominate, red-shanked form, P. n. nemaeus, though in the far south, greatly reduced red on the legs suggests intergradation with another form. Our records are overwhelmingly from evergreen or semievergreen forest and from a wide altitudinal range (200–1600 m). In most sites habitat was little degraded, but whether this reflects choice for such habitats, or the generally lower hunting pressure within them, is unclear. The largest population occurs over 3000 km ² of the Nam Theun basin and surroundings, encompassing the protected areas of Nakai-Nam Theun, Hin Namno and the proposed Nam Theun Extension. This is the most important population of red-shanked langurs in the world. Laos supports globally the vast majority of their conservable population. Douc langurs are threatened in Laos by habitat fragmentation increasing their vulnerability to the existing high hunting levels. They are a favored target for local consumption and for local and Vietnamese hunters and traders. Protective measures should center around implementing habitat conservation and antihunting measures in the recently-declared National Biodiversity Conservation Areas. A recent government initiative to reduce gun use in rural areas is likely to have a strong positive effect on the population. The best protection for some time will remain the inaccessibility of their habitat. Accordingly, road-building into remote forest and piecemeal clearance at its edges should thus be minimized. Cross-border attention should be given to wildlife trading, including measures to reduce market demand.     

Ovarian Cycle and Effect of Social Changes on Adrenal and Ovarian Function in Pygathrix nemaeus

To assist captive breeding of the endangered red-shanked douc langur (Pygathrix nemaeus), basic knowledge on female reproductive physiology is important. We aimed 1) to characterize the pattern of fecal estrogens and progestogens during the ovarian cycle and 2) to use the information to provide reliable data on ovarian cycle characteristics. Moreover, we examined the potential impact of a change in group composition on ovarian activity and adrenal function, the latter being measured by fecal glucocorticoid excretion. We collected fecal samples during 2 mo from 5 adult females of 3 groups under undisturbed conditions and from the same 5 adult females and 2 juvenile females and 2 adult males during 3 mo during which there were changes in housing and group composition. During the undisturbed period, measurement of fecal 5-P-3OH, a major progesterone metabolite, and total estrogens revealed in all adult females a cyclic pattern, from which we documented a cycle length of 26.4 ± 1.8 days, comprising a follicular phase of 13.1 ± 2.9 days and a luteal phase of 14.8 ± 1.2 days. In contrast, during the period of social changes, 3 of the 5 females showed clear signs of cycle irregularity as indicated by extended follicular phases, abbreviated luteal phases and/or anovulation. Moreover, the period of social changes was associated with an overall significant elevation in fecal glucocorticoid excretion. Our data provide the first detailed information on the endocrine characterization of the ovarian cycle in Pygathrix nemaeus and suggest that social changes have the potential to impair ovarian function, likely as a result of increased activation of the HPA-axis due to stressful situations. However, because of relatively small sample size, particularly concerning the latter finding, more data are needed to confirm these results.     

Metrical dental analysis on golden monkey (Rhinopithecus roxellana)

Dental variation in the Chinese golden monkey (Rhinopithecus roxellana) is here evaluated by univariate, bivariate, and multivariate analyses. Allometric analyses indicate that canines and P3s are positively, but other dimensions negatively scaled to mandible and maxilla, and to body size. With the exception of the mesiodistal dimensions of I₁ and M₃, and the buccolingual dimension of P₄, mandibular dental variables show similar scaling relative to body size. Analysis of residuals shows that males have significantly larger canine, P³ and buccolingual dimensions of the postcanine teeth (M² and M³) than females. A significant difference in shape between the sexes is found in the buccolingual dimension of the upper teeth, but not in the mandible. Unlike the situation in some other species, female golden monkeys do not exhibit relatively larger postcanine teeth than males. In fact, the reverse is true, expecially for M²s and M³s. The fact that most of the dental variables show low negative allometry to body size might be related a cold environment that has led to the development of larger body size with reduced energy loss. When the raw data are examined by Discriminant Function Analysis the sexes are clearly distinguishable.     

The seasonal daily travel in a group of Sichuan snub-nosed monkey (Pygathrix roxellana) in Shennongjia Nature Reserve,China

The seasonal daily travel of a group of snub-nosed monkey (Pygathrix roxellana) was investigated using the group’s straight-line distance method. The group was followed from dawn to dusk for 30 consecutive days during each season to encompass all aspects of daily travel patterns. The results showed that in Summer and Autumn, the mean daily travel distance (m) was significantly longer than in Winter and Spring. There was no significant difference in the mean daily travel distance between Summer and Autumn or between Winter and Autumn. The mean travel distance (m/hr) during daytime was significantly higher in Summer and Autumn than in Spring, and in Autumn than in Winter. The travel of the group in all seasons had similar patterns. Traveling showed morning and afternoon peaks, with a rest period at the noon in a day. Seasonal food availability, length of daytime, and mean travel distance (m/hr) during daytime might have contributed to the different daily travel distances in different seasons.     

Report on the distribution,population, and ecology of the yunnan snub-nosed monkey (Rhinopithecus bieti)

The Yunnan snub-nosed monkey (Rhinopithecus bieti), an endangered species in China, has received more protection in theory than in practice. Therefore it is on the very verge of extinction. The population of the species was estimated less than 2,000 individuals spread in 19 distinct groups. It was confirmed that the monkey was confined to the Yunling Mountain System, the area between the Yangtze River (Changjiang, aka Jinshajiang) to the east and the Mekong River (Lancangjiang) to the west. We further concluded that a lowland belt to the east, about 100 km long and 20 – 30 km wide was not suitable habitat for the monkeys, and appeared to serve as the natural ecogeologic barrier for the species. Our results indicated that the southern limit of the distribution was at Longma (26°14′N), and that the northern limit of the distribution was at Xiaochangdu (29°20′N). The distribution area of the species was substantially smaller than previously estimated. There were substantial ecological differences between the southern and northern parts of the species range. The monkey was found only in fir-larch forest.     

Birth spacing in langur monkeys (Presbytis entellus)

This paper presents 10 years of reproductive data on birth interval length and 5 years of data on reproductive behavior postpartum from a captive colony of gray langur monkeys (Presbytis entellus)housed in Berkeley, California. Birth intervals of females following different pregnancy and nursing schedules are compared. Females whose infants survive to the age of 9 months have a median birth interval of 15.4 months. The experimental separation of mothers from infants for a period of 2 weeks, 6 to 9 months postpartum, had no significant effect on the median birth interval length. Females experiencing a pregnancy failure or the loss of a neonate had median birth intervals of 9.6 and 10.7 months, respectively. These intervals were significantly shorter than the birth intervals of females whose infants survived to 9 months, showing that the presence of a nursing infant delays the female’s time to next conception by approximately 5 to 6 months. Females experienced a median of three estrous periods (two estrous cycles) before conceiving postpartum, regardless of pregnancy outcome or length of infant survival, and females rarely conceived during their first estrous period postpartum. Weaning did not occur until after the mother’s next conception. These data indicate that, in populations of langurs characterized by average birth intervals of 15 to 16 months, the loss of an infant after the age of 5 to 6 months will not accelerate a female’s ability to conceive or shorten the birth interval length. The available data on birth spacing from populations of free-ranging langurs are reviewed. It could not be demonstrated that non-Himalayan populations are characterized by birth intervals which are as long as 20 to 24 months. Rather, it is suggested that female langurs inhabiting seasonally arid sites, such as Jodhpur, Abu, and Dharwar, may be capable of producing infants on the average of every 15 to 16 months. Flexibility in the timing of births and the lack of well-defined birth seasons at these sites may be explained by this species’ dietary and digestive adaptations. Additionally, data on birth spacing and the age of missing infants from the above field sites, where it has been suggested that infanticide following changes in male leadership occurs habitually, do not lend support to the sexual selection hypothesis of infanticide as proposed by S. Hrdy (1974, 1977).     

Comparisons of Suspensory Behaviors Among <Emphasis Type="Italic">Pygathrix cinerea</Emphasis>, <Emphasis Type="Italic">P. nemaeus</Emphasis>, and <Emphasis Type="Italic">Nomascus leucogenys</Emphasis> in Cuc Phuong National Park,Vietnam

In our study at the Endangered Primate Rescue Center of Cuc Phuong National Park, Vietnam, we aimed first to assemble a positional behavioral profile of captive gray-shanked (Pygathrix cinerea) and red-shanked (P. nemaeus) doucs that relates to the use of forelimb suspensory postures and arm-swinging locomotion. The profile is of interest because researchers have documented that red-shanked doucs more frequently use suspensory postures and locomotions than other colobines do. We confirmed that red-shanked doucs commonly use suspensory positional behaviors and also that gray-shanked doucs use suspensory behaviors at similar or even higher frequencies than those of red-shanked doucs. Our second goal was to assemble a preliminary kinematic profile of suspensory locomotion in Pygathrix within the context of the arm-swinging locomotion exhibited by northern white-cheeked gibbons, Nomascus leucogenys. Mean forelimb angles at initial contact and release of arm-swinging behaviors were remarkably consistent among gibbons and doucs despite the fact that gibbons typically used more continuous brachiation. Doucs also exhibit a greater range of forelimb angles than gibbons do. In addition, trunk orientation tends to be less vertical at initial contact for doucs than for gibbons, perhaps owing to the frequent use of quadrupedal sequences directly before or after forelimb suspension. Our behavioral and kinematic analyses add to the emerging realization that Pygathrix is capable of, and frequently expresses, a range of suspensory positional behaviors, including brachiation.     

Mandibular morphometric variation among Chinese cercopithecoids and the unique structure of the snub-nosed monkey (<Emphasis Type="Italic">Rhinopithecus</Emphasis>) mandible

In order to understand how mandibular structure differs among the Chinese cercopithecoids (Rhinopithecus, Trachypithecus and Macaca), particularly the uniqueness of the snub-nosed monkeys (Rhinopithecus), we analysed ten mandibular measurements by principal components analysis (PCA), and examined scaling patterns. The results provided by the PCA illustrated differences due to size among the cercopithecoids and the relationship between colobines (Trachypithecus and Rhinopithecus) and cercopithecines, in which macaques (Macaca) are included. Allometric analysis indicated that, biomechanically, there is not a marked difference between macaques and leaf-eating monkeys. This may be associated with the fact that both share some similar ecology and niches in south and southwest China. The snub-nosed monkeys exhibit a significantly more robust mandible, evident in the symphysis, corpus, condyle, and masticatory momentum arm. This supports the hypothesis, based on the study of dental structure, that Rhinopithecus is a unique group in Asian Old World monkeys (OWMs) and has developed some unique characteristics in order to adapt to the tough food available in the severe cold climate of the Plateaux of Qinghai-Tibet, Yun-Gui and Qingling in China.     

The reproductive behavior of golden monkeys in captivity (Rhinopithecus roxellana roxellana)

The reproductive behavior of two captive harem breeding groups of golden monkeys was observed over one mating season and compared to non-seasonal reproductive behavior. Observation of over two thousand sexual interactions suggests that 1) females were responsible for 95% of all sexual solicitations (proceptive behavior), of which the typical pattern was prostration, while males were responsible for only 5%; 2) 17% of female solicitations were interrupted by another female; 3) 52% of female solicitations resulted in mounting by males; 4) the frequencies of solicitations and receipt of mounts and ejaculations varied greatly among females; 5) the frequency of ejaculations, the ratio of ejaculations to mountings, and ejaculation patterns were different between two males, and 6) the golden monkey is a seasonal breeding animal.     

Isolation and characterization of 11 microsatellite loci for the Sichuan snub-nosed monkey,Rhinopithecus roxellana

We report on the isolation and characterization of 11 microsatellite loci in the Sichuan snub-nosed monkey (Rhinopithecus roxellana) from AC-enriched genomic libraries. 20 microsatellite loci were screened from the libraries, of which 11 were polymorphic. The number of observed alleles among 32 samples of snub-nosed monkey ranged from three to nine. The observed and expected heterozygosity were 0.071–0.815 and 0.201–0.819, respectively. The high variability revealed in this study should be useful tools for further study on social structure and population genetics of snub-nosed monkey in the future.     

The diet of the capped langur (Presbytis pileata) in a moist deciduous forest in Bangladesh

Capped langurs (Presbytis pileata) in Madhupur National Park in north-central Bangladesh have an annual diet that is comprised largely of mature leaves (42% of 20,460 total feeding records). Among colobine monkeys, only some populations of red colobus (Procolobus badius) have a diet richer in mature leaves. New leaves (11%) and fruit (24%) are the other annually important dietary items. Seasonal breakdown of this diet, however, revealed that during the monsoon months of May through September theP. pileata diet is approximately 50% fruit, including pulpy ripe fruit. This is also the period of maximum fruit availability. Data on diet and food availability indicate that while capped langurs subsist on mature leaves during the dry season (80% of diet from November to March), they select fruit and new leaves and switch to these foods whenever they are available. These data support the hypothesis that the colobine feeding strategy is adapted to cope with seasonal food scarcity.     

湖北省巴东县小神农架地区川金丝猴的种群调查

The population activities of golden monkeys (Rhinopithecus roxellana) in the Xiaoshennongjia of Badong county,Hubei Province had been surveyed by consecutively tracing and grossly counting from 0ct.2000 to June 2002.The result indicated the anmount the golden monkey that iuhabit in here about 600-800 individuals.They moved clockwise in a circular track.236 golden monkeys of 2 groups had recorded by video camera during survey in Apr.2001,among them there were 59.05% adult and 40.95% of underage,the rate was 1:0.9,the sex ratio of adult was 1:1.38 (male:female).117 individuals of three different groups were recorded in random in 2002,among them were 56.41% of adult and 43.59% underage,the rate was 1:0.67,the sex ratio of adult was 1:1.2.The young were hem from the beginning the month of March.     

利用尿液中的雌二醇、孕酮含量监测雌性川金丝猴的月经周期和妊娠

During two consecutive mating seasons from August 2001 to December 2002, we observed the sexual behavior of Sichuan golden monkeys in the Chengdu Zoo and the Shanghai Wild Animal Park. We collected urine samples from females in the early morning. We also measured urinary estradiol and progesterone levels using radioimmunoassay. Based on the estradiol concentration during the menstrual cycle, we discovered that the length of the menstrual cycle was 286.33 1.67 days. The length of pregnancy was about 200 days. The level of estradiol after impregnation was significantly different with the level during the ,same period in the non-receptive part of the cycle. Thus we could diagnose early pregnancy in female Sichuan golden monkeys by checking their urinary estradiol level .     

Feeding and ranging in the Mentawai Island langur (Presbytis potenziani)

Presbytis potenziani is found only on the Mentawai Islands, Indonesia, and its ecology and feeding and ranging behavior have been little studied. I studied 10 groups ofPresbytis potenziani in the primary forests of North Pagai Island, Mentawai, Indonesia.P. potenziani used primarily the upper strata of the forests for feeding, movement, and resting. Groups remained cohesive during their daily activities, ranged between 100 to > 1000 m daily, and occupied home ranges of ≤ 40 ha. Neither sex predominantly initiated group movement. Locomotion was primarily quadrupedal, with frequent leaping. P. potenziani showed two feeding peaks, one in early morning and one during midafternoon. P. potenziani fed mainly on climbers and trees of the Dipterocarpaceae. They ate primarily leaves, but also fed on fruits and other plant parts.     

Lactation in the Japanese monkey (Macaca fuscata): Yield and composition of milk and nipple preference of young

Changes in the yield and chemical composition of milk, together with those in the nipple preferences and suckling behavior of infants, were followed in three lactating Japanese monkeys rearing single infants under laboratory conditions at monthly intervals for six months after their paturition. Milk accumulating in the mammary glands during a 4-hr separation of the infant was collected by milking under anesthesia with the aid of a physiological dose of oxytocin. The stage of full lactation appeared to last for about two or three months after parturition. The milk at this stage contained 14.0% of total solids, 4.2% of lipids, 1.6% of proteins, and 6.2% of lactose, and the concentrations of Na, Cl, and K in the milk water were 7.4, 15.1, and 5.9 mM, respectively. From the 9th or 13th week of lactation onwards, according to the individual, the milk composition changed appreciably and the time during which the young left hold of the mother's nipple also increased. The weaning of young in the Japanese monkey appears to begin during the 3rd or 4th month of age. The milk production then wanes and almost ceases by the end of the 6th month. The nipple preference of the young was generally established completely by the 3rd, or the 8th at latest, week of age. However, no difference in either the yield or composition of the milk secreted was found between the mammary glands of the preferred and non-preferred sides. Without regard to the apparent nipple preference, infants seem to ingest milk from the mother's breasts of both sides. Accurate estimation of the rate of milk production could not be achieved, but the rate was expected to be 150–200 g/day at the height of lactation based on the relation between the mother's body weight and the milk production rates of other primate species. A disparity was noted between the observed and estimated values for the milk yield, and a diurnal fluctuation in the milk secretion of the Japanese monkey was inferred. This study was conducted through the official system of the Primate Research Institute, Kyoto University, for cooperative research work with other institutions.     

Conflict and postconflict behaviour in captive black-and-white snub-nosed monkeys (<Emphasis Type="Italic">Rhinopithecus bieti</Emphasis>)

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) have almost never been the subject of any behavioural observations in captivity. This study was aimed at providing preliminary information about agonistic and reconciliation behaviour in a group kept at the Kunming Institute of Zoology in China. Established procedures were used for this investigation (i.e., the postconflict/matched-control method and the time-rule method). Intra-group aggression rates were quite low. Postconflict affiliation as well as selective attraction of former opponents to each other following conflicts was demonstrated. Former opponents contacted each other earlier in postconflict periods than in matched-control periods. The average conciliatory tendency of all focal individuals combined was 54.5%. After an agonistic interaction, the first affiliative contact between former aggressors usually took place within the first minute. The behaviours most often shown as first affiliations after a conflict were body contact, mount, touch, and hold-lumbar, of which the latter is an explicit reconciliatory gesture. Furthermore, the adult male intervened non-aggressively in 84% of all conflicts (n=25) among the adult females. Overall, the patterns of aggression and reconciliation observed in R. bieti bear many of the traits that characterise tolerant primate species.     

A phylogenetic study of titi monkeys,genusCallicebus, based on cranial measurements: I. Phyletic groups ofCallicebus

Examinations of 23 forms ofCallicebus were made to elucidate their phylogenetic relationships based on cranial measurements. Multivariate statistical methods of distance analysis utilizing Q-mode correlation coefficients and principal component analysis were employed. As a result, the following five distinct groups were recognized morphometrically among the 23 species and subspecies: theDonacophilus, Cupreus, Moloch, Personatus, andTorquatus groups. Moreover, the phenetic characters of cranial size, karyotype, pelage coloration, and geographic range were consistent with the results of this group classification. It could be safely concluded therefore that these groups represented phylogenetically independent groups, in view of the fact that the rate of character differentiation was not appreciably different among closely related groups. Of the five groups, thePersonatus andTorquatus groups were respectively considered to maintain a higher peculiarity of character differentiation within theCallicebus phylogeny, since these two groups individually displayed the higher magnitudes of differentiation in both their craniometric shape and some phenetic features. Conversely, the other three groups were considered to be closer to each other in theCallicebus phylogeny.     

Neural connections between the brain and the pineal gland of the golden hamster (Mesocricetus auratus)

Summary Neurons projecting from the brain to the pineal gland via the pineal stalk were investigated in the golden hamster with the use of the retrograde horseradish-peroxidase tracing method both in vivo and in vitro. Labelled perikarya were observed in the medial and lateral habenular nuclei as well as in the posterior commissure. Single cells located in the ependymal lining of the pineal- and suprapineal recesses were also retrogradely labelled. These results show that a distinct central innervation of the pineal gland exists in the golden hamster, in agreement with findings in other mammalian species investigated by means of a similar methodology. In addition, also direct signals from the cerebrospinal fluid to the parenchyma might be conducted via cells located within the ependymal layer of the pineal- and suprapineal recesses.This study was supported by grants from the Deutscher Akademischer Austauschdienst to M.M. (312/dk-4-is), the Deutsche Forschungsgemeinschaft to H.W.K. (Ko 758/2-2, 2-3), and the Carlsberg Foundation     

Morphological variations of the cranium within the genusLeontopithecus

Multivariate analysis methods were applied to the cranial measurements ofLeontopithecus. InLeontopithecus chrysomelas, the face is generally narrow and the cranial shape is relatively unique. Especially, the male has extremely narrow face and quite unique cranial shape amongLeontopithecus. Leontopithecus rosalia has the broad face compared with the other species. The cranial size ofL. rosalia is as large as that ofL. chrysomelas. Male ofLeontopithecus chrysopygus is the largest in overall size of the cranium, and has the widest braincase.