Search

Despite decades of research, little is known about morphometric differences within the dentition of Asian colobines. Although some differences, such as the M3 hypoconulid, are often cited as distinct among genera, no comprehensive assessment has been made. The objectives of this study were to document size and shape differences in third molars in eight Asian colobine genera, including Kasi, Nasalis, Presbytis, Pygathrix, Rhinopithecus, Semnopithecus, Simias, and Trachypithecus, and to quantify length differences for all molars in order to understand the potential impact of an occlusal surface area that includes the hypoconulid. To achieve these objectives, the most extensive survey yet published of Asian colobine dentition was conducted. Differences within and among genera for continuous and categorical variables were analyzed using descriptive statistics, chi-square, t-tests, and post hoc comparisons. Results indicate that species of Presbytis differ from all other Asian colobines in both the size and shape of the maxillary and mandibular third molars. Specifically, M3 of Presbytis is relatively shorter in length and less likely to exhibit a hypoconulid optimally positioned for occlusion with M3. Moreover, Presbytis expresses concomitant changes in the maxillary third molar such as absence of a distal shelf and/or a distal cusp with separated crests. We conclude that shape and size changes impact the molar size sequence patterns of Presbytis, set- ting this genus apart from all other Asian colobine taxa. These differences may reflect variation in overall body size, dietary adaptation, and phylogeny. [ABSTRACT FROM AUTHOR]

Within a species, habitat quality may be a factor causing different activity budgets between populations. The habitat of white-headed langurs (Trachypithecus leucocephalus) has been seriously disturbed in Fusui Rare and Precious Animal Nature Reserve, China, where we carried out a study of their socioecology from September 1997 to September 1998. We collected data on langur activity budgets from the main population located in the central part of a group of limestone hills. We classified habitat quality into 4 grades according to the extent of human disturbance. We showed that the two main study groups of white-headed langurs spent on average 50% of time resting, 13% feeding, 18% moving (including foraging), 11% grooming, and 7% playing. Langur time budgets showed no significant seasonal change, but they differed among different sex-age classes. Infants and juveniles spent about 20.3% of time playing, whereas adults spent only 0.2% playing. The group in high quality habitat engaged less in feeding and more in playing than the group in low quality habitat did. Habitat quality influenced the playing time of young white-headed langurs and may be vital to their successful maturation. [ABSTRACT FROM AUTHOR]

The ability to differentiate among calls from different individuals has been shown for a number of animal species and several functions have been suggested. One hypothesis, developed for lions (Panthera leo), is that the ability to distinguish between calls from neighbour versus strange males is linked to the avoidance of infanticidal ( i.e. strange) males. Since infanticide is widespread among primates, we tested the applicability of this hypothesis to Thomas langurs (Presbytis thomasi). Young adult males, that mostly reside in all-male bands or are solitary (called AMB males), were more likely to be infanticidal than adult, usually older, males that reside in mixed-sex groups (called MSG males). We use playbacks to demonstrate that Thomas langurs are able to differentiate between loud calls from AMB male strangers and MSG male strangers. Thomas langur males responded more vigorously to playbacks of calls from AMB (i.e. more likely to be infanticidal) males than to calls from MSG males. Females showed a more cautious response to the calls from AMB males than to the calls from MSG males. Both these reactions are in accordance with the infanticide hypothesis and suggest that Thomas langurs differentiate between loud calls of AMB and MSG stranger males and incorporate this information in their behaviour to avoid infanticide. [ABSTRACT FROM AUTHOR]

We studied the feeding ecology of white-headed langurs (Trachypithecus leucocephalus) from September 1997 to September 1998 in Fusui Rare and Precious Animal Reserve, SW Guangxi, China. We collected data in the central part of a group of limestone hills where the main population pool of langurs was located. The langurs fed on 50 plant species (belonging to 42 genera from 28 families) out of 164 species in the habitat (belonging to 112 genera from 48 families). Most of the food plant species were not common in the habitat. There are 16 important food species, including 6 key species. White-headed langurs were extremely folivorous, feeding mainly on young leaves (75% of total feeding records) of a broad range of less common plant species, which were in less disturbed areas. Thus, langur groups in high quality habitat had greater access to preferred foods, and the future of langurs in the Reserve may depend on immediate cessation of tree felling. [ABSTRACT FROM AUTHOR]

Males in many primate species give loud calls. Lifetime changes in loud calls may be due to either age or social changes. We examined loud call characteristics, loud call production and levels of fecal testosterone among 4 life-phases of male Thomas langurs (Presbytis thomasi ): all-male band (AMB), early, middle, and late life-phase in mixed-sex groups. Discriminant analyses showed that a high percentage of loud calls could be assigned correctly to the proper life-phase. The most significant change in loud call characteristics is an increase in tonal units and duration from the AMB to the early life-phase, accompanied by a decrease in non-tonal units. Since adult AMB males have a similar age to that of early life-phase males, we suggest that social rather than age-related changes underlie the loud call differences between AMB males and early life-phase males. This could also be related to the increase in testosterone levels from the AMB to the early life-phase. In addition, we postulate that females may use loud call characteristics as a cue to choose between young and old males once they decided to leave their current male, and possibly also as a cue to decide to leave their current male as he enters his late life-phase. [ABSTRACT FROM AUTHOR]

PO-1-Lu, the endogenous type D retrovirus of langurs (Trachypithecus obscurus) has previously been considered a progenitor to the prototype type D retrovirus, Mason Pfizer monkey virus (M-PMV/SRV-3), that became established in macaque monkeys (Macaca spp.) following a zoonosis. This study reevaluates this hypothesis to include other exogenous SRVs. New sequence information from the gp70(SU)-encoding region of PO-1-Lu shows striking similarity to the newly identified exogenous langur retrovirus, SRV-6, recently isolated from the Hanuman Langur (Semnopithecus entellus). An unrooted, bootstrapped neighbor-joining tree derived from env gene nucleotide sequences shows PO-1-Lu and SRV-6 appear more closely related genetically to SRV-2 than SRV-1 or SRV-3 (M-PMV). This is also reflected in our observations that the M-PMV envelope glycoprotein precursor gPr86Env and gp70(SU) were antigenically distinct from PO-1-Lu, although the gp22(TM) glycoproteins were antigenically cross-reactive. The potential that SRV-6 represents an exogenous form of PO-1-Lu that has arisen following a recent zoonosis is discussed. [Copyright &y& Elsevier]

We describe the activity patterns and time budgets of white-headed langurs that were confined to about 4 km[sup 2] of Longlin habitat in Fusui County, Guangxi Province, China. Between February and December 1996, we observed 6 langur groups monthly via group focal sampling and continuously recording the behavior of a focal group. Our results indicate that the langur groups selected stone caves on cliffs as sleeping sites. The daily activity pattern outside caves had 8 stages: (1) leaving the cave in the early morning; (2) moving and resting; (3) morning feeding; (4) moving a long distance; (5) resting at noon; (6) afternoon feeding; (7) moving back to the cave, and (8) entering the cave. Over the year, langurs spent a daily average of about 11.5 h outside caves and about 12.5 h inside caves. Moving accounted for 7% (spring), 7% (summer-autumn) and 13% (winter) of the time budget, and langurs spent 9% (summer-autumn) and 14% (spring) to 20% (winter) of their time feeding. Resting accounted for 79% of the time budget in spring, 84% in summer-autumn, and 57% in winter. Sunbathing only occurred in winter and accounted for about 10% of the time budget. One-way ANOVA and multiple range tests demonstrated that time budgets differed significantly among seasons. Langurs spent significantly more time feeding and moving in winter than in spring and summer-autumn, but significantly less time resting in winter than in spring and summer-autumn. [ABSTRACT FROM AUTHOR]

Food habits of tigers Panthera tigris in terms of prey abundance were studied in the semi-arid deciduous forests of Ranthambhore National Park, western India, between November 2000 and April 2001. Wild prey availability was assessed by line transects (n=8) and prey selection by the tigers was determined from analysis of scats (n=109). Compared to some other parts of the country, prey abundance was found to be high at 96.65 animals km−2. Chital Axis axis was the most abundant wild prey in the study area, followed by common langur Presbytis entellus, sambar Cervus unicolor, nilgai Boselaphus tragocamelus, wild pig Sus scrofa and chinkara Gazella bennetti. Chital (c. 31%) and sambar (c. 47%) constituted the bulk of the tigers' diet and were preferred prey. Nilgai and chinkara contributed minimally to the tigers' diet (c. 5–7% and <1%, respectively) and were used less than their availability. Domestic livestock made up 10–12% of the tigers' diet. The average weight of an animal consumed was between 107 and 114 kg reflecting a preference for large prey. The analysis reveals that parts of Ranthambhore have high prey abundance, thus making it important for long-term tiger conservation. Despite the high prey abundance, tigers were still considerably dependent on domestic livestock, posing challenges for the park management to resolve potential areas of conflict. [ABSTRACT FROM AUTHOR]

Abstract Individual and contextual differences in male loud calls of wild Thomas langurs (Presbytis thomasi ) were studied in northern Sumatra, Indonesia. Loud calls were given in the following contexts: morning calls, vocal responses to other groups, between-group encounter calls and alarm calls. Loud call spectrograms were analysed for a large number of variables. With discriminant analyses, 14 variables were found to be important in distinguishing individuals and contexts. Loud calls were assigned to the correct individual in 95.6% of the cases (91.8% with ‘leave-one-out’ validation) and to the correct context in 52.2% of the cases (39.0% with ‘leave-one-out’ validation). Further analyses with two-way anovas showed significant differences in both temporal and frequency variables between individuals and contexts. Loud calls seemed to differ between the contexts in functionally meaningful ways, relating to the distance of the intended receivers and to the urgency of the message. Observation showed that females in the caller's group collected infants more often in the between-group encounter context and in the alarm call context than in the vocal exchange context. These differential responses suggest that the monkeys also perceive the measurable differences in loud call characteristics between the various contexts. [ABSTRACT FROM AUTHOR]

The white-headed langur is classed as a category I species under the Wild Animal Protection Law in China. It is distributed only in Karst hills in four counties (Longzhou, Ningming, Chongzuo and Fusui), in the southern Guangxi province of China. The Mingjiang River and the Zuojiang River form its southern, western and northern boundaries, and the Shiwandashan Mountains restrict its range in the east. Population surveys conducted in the 1980s showed that there were a total of 630 individuals in Guangxi, including 244 in Longzhou and Ningming counties, 117 in six fragments of Chongzuo County and 272 in nine patches of Fusui County. Surveys conducted by our group and Guangxi Forestry Bureau indicated that a total of 580–620 white-headed langurs still live in the above four counties, including 210–240 in Longzhou and Ningming, 90–100 in Chongzuo and 250 in Fusui. According to our statistics, only about 200 km2 of habitat remains within the current range of the white-headed langur and this is separated as a total of 16 patches in 13 townships. Shangjin and Xiangshui in Longzhou county and Tingliang and Tuolu in Ningming, form the largest patch of the range, with total area of 68 km2, while in Chongzuo and Fusui County, the habitat is heavily fragmented with six patches of 43.5 km2 in Chongzuo and nine patches of 88 km2 in Fusui. At present, the white-headed langur is still suffering from heavy habitat deterioration and human disturbance such as cultivation, tree-cutting for firewood, and poachings even though the government has made many efforts to protect this endangered species, such as putting it as a category I species for protection and designating the nature reserve and stations. [Copyright &y& Elsevier]

Animals may behave aggressively towards neighbours. For several bird species it has been shown that males react more vigorously towards calls of neighbours from the centre of their home range than from the edge. This is usually explained by assuming that the centre of a home range is of higher value to a male than the edge. To test these ideas for a primate species, we conducted experiments with playbacks of loud calls on wild male and female Thomas langurs (Presbytis thomasi). These animals may defend resources in their range or protect their offspring from infanticide and males may defend their females. In natural situations between-group encounters in the centre of a home range by the intruding neighbour are more often accompanied by infanticidal attempts than encounters at the edge. Loud calls of neighbours played back from the centre of the home range caused a more vigorous reaction from the resident male than calls from the edge. However, males in food-containing trees did not respond differently to edge playbacks from males in non-food-containing trees. Although males seem to defend resources and not mates, male behaviour may be best explained by defence of infants against infanticide. Female behaviour is best explained by resource defence. [ABSTRACT FROM AUTHOR]

A number of studies on birds and mammals have shown that individuals respond differently to neighbour and stranger call playbacks. This response is generally thought to be adaptive, because differentiating calls from neighbours and strangers can prevent the costs of unnecessary contests. In addition, it has recently been suggested that female lions use call recognition to avoid infanticidal males. In this paper we show that Thomas langur (Presbytis thomasi) males react more vigorously towards calls from strange than neighbouring males. It is hypothesised that, although differentiating between calls from different males can be useful to reduce unnecessary contests between the males, discriminating between individual calls is important because it might reduce the risk of infanticide. [ABSTRACT FROM AUTHOR]

The distribution of golden langurs (Trachypithecus geei ) is limited to a small area of western Assam in northeast India and Bhutan between the rivers Manas in the east, Sankosh in the west, and Brahmaputra in the south. It is one of the most seriously endangered primate species of India. A comparative analysis based on satellite images taken in 1988 and 1998 showed a 50% loss of original golden langur habitat. Data on population dynamics collected using line transect and total count methods are presented here. An average group size of 8.2 (range 4.0–22.0) individuals was recorded. A total of 1,064 individuals were counted living in 130 groups. The sex ratio was 1.9–2.5 adult females for each adult male. A low percentage of juveniles and infants suggests that the population is unstable. Most of the groups had only one adult male. Small group sizes, isolated distribution, proportionately few infants and juveniles, and degrading habitat are all causes of concern. Demographic trends indicate a decline in the golden langur population. Am. J. Primatol. 55:15–23, 2001. © 2001 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Presents several abstracts related to primates published in the May 2001 issue of the "American Journal of Primatology." "Flowers and Foliage: How Important Are These to Malagasy Lemurs?," by M. Muchlinski and D. Ovedorff; "The Effect of Menstrual Cycle Phase on Cortisol Excretion in Female Cynomolgus Monkeys (Macaca fascicularis)," by R. Stavisky, D. Brandenberger, M. Hook, E. Russell, J. Kaplan and P. Whitten; "Discovery of a Contact Zone Between Golden Langurs (Trachypithecus geei) and Capped Langurs (Trachypithecus pileatus) in Bhutan," by T. Wangchuk, Y. Kawamoto and M. Aimi.

Focuses on the paternity analysis of alternative male reproductive routes among the langurs, Semnopithecus entellus, of Ramnagar, Nepal. Establishment of paternity by DNA analysis from feces; More than half of the total number of offsprings sired by the alpha male in a multimale group; Lower mean number of infants sired by alpha males during their whole tenure as alpha.

The Shannon-Wiener diversity index (H) has been used to characterize grooming relationships among adult female primates. To make comparisons among different groups, the value of H has been divided by the maximum value it can reach for a particular group size. This ratio, the grooming diversity ratio (GDR), has been used to test predictions from hypotheses that may explain the distribution of social relationships among adult female primates. Using grooming data from different primate populations and random computer simulations I show that the mean value of H and GDR are positively affected by the ln of the mean number of grooming bouts recorded per dyad (LnMNBD) and negatively by the coefficient of variation in the frequency of grooming bouts recorded for the females within a group (CV). These two variables reflect the combined effect of sampling effort and the rate of interactions among individuals (and their variance) and should be statistically controlled to make sensible use of H or GDR. After controlling for LnMNBD and CV, I found no significant effect of female group size, the degree of female involvement in inter-group encounters and the patterns of female dispersal on the mean value of GDR. The socioecological model of female social relationships (Sterck et al., 1997) predicts that groups categorized as resident-egalitarian should have higher GDRs than resident-nepotistic ones. I find some support for this prediction when using a data set where some species contributed more than one data point but not when using mean values per species as in the previous analyses. This result may be confounded by a phylogenetic effect: langurs seem to have more diverse relationships than other primates. Data from more species are necessary to corroborate these results and to disentangle the effect of phylogeny from that of the social categories since most monkey groups characterized as resident-egalitarian were langurs. [ABSTRACT FROM AUTHOR]

To date, it is not known whether the seasonal occurrence of sexual behavior and mating in free-ranging Hanuman langurs at Ramnagar, Nepal, is correlated with seasonal changes in female ovarian function, and, if so, which factor(s) triggers the onset of the reproductive period. Using non-invasive fecal hormone analysis in combination with behavioral observations, this study was carried out to: 1) investigate and characterize seasonal patterns of ovarian cyclicity and timing of conception in wild langur females living in a highly seasonal habitat; and 2) examine the relationship between seasonal patterns of ovarian cyclicity, behavioral estrus, and female physical condition. Behavioral data and fecal samples were collected during a total period of 14 months from nine females living in a multi-male group. Physical condition of the females was assessed monthly by visual inspection, using a seven-fold scale. Ovulatory cycles and timing of conceptions were identified by the measurement of immunoreactive pregnanediol glucuronide (iPdG) in extracted feces. Hormone profiles in individual females revealed a clearly seasonal distribution in the occurrence of ovulatory cycles, which were restricted to the period from July to October. The distribution of female estrus behavior showed a similar seasonal pattern, and in total 88.2% of all estrus periods observed in the focal females were accompanied by ovulation. Onset of ovarian cycles as well as mating activities were strongly correlated with the onset of the rainy season. Females conceived, on average, in their second ovulatory cycle (pregnancy length: 211.6 ± 3.4 days), with timing of conception being confined to the months when animals showed an improved physical condition. Collectively the present data clearly suggest that in seasonally-breeding langurs at Ramnagar, ecological conditions (rainfall, food availability, and quality) influence the onset of ovulations and timing of conceptions. Am. J. Primatol. 51:119–134, 2000. © 2000 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

A recent systematic survey program of protected areas in Laos documented douc langurs ( Pygathrix nemaeus) widely between 14°25′N and 18°38′N. 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[sup 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. [ABSTRACT FROM AUTHOR]

Describes an extinct subspecies of the Javan lutung, Trachypithecus auratus sangiranensis, based on an isolated, tooth-bearing upper-jaw. Location where the specimen was found; Morphological similarities of the fossil monkey to the living species of leaf monkey from Java; Etymology.

In this paper, we investigate how the number and context of male loud calls of Thomas's langurs (Presbytis thomasi) change over a male's tenure, in relation to changes in the intensity of male mate competition and relative male strength. We also investigate how the calls' impact on the behavior of receivers varies over tenure phases. Thomas's langurs live in one-male multi-female groups; only males produce loud calls; both males and females disperse from their natal groups; female secondary dispersal is also common, and infanticide occurs. The life-span of a group is, as a rule, restricted to the tenure of its reproductive male (median tenure length is 72 months). Male tenure in bisexual groups was divided into three phases: the early phase (no infants yet), the stable middle phase, and the late phase (last year). Because AMBs remained after all females had left a male, they were treated as a fourth phase. We hypothesised that the tendency to answer another male's calls decreases with distance because a male will invest less when answering becomes less relevant. The tendency to respond to a loud call by an extra-group male indeed decreased with distance, which suggests that males invested less in (costly) calling behavior when the chance of an interaction with that male was low. Extra-group males seemed to recognise males of new groups: they did not discriminate between medium and far distances in answering calls from (relatively unfamiliar) early tenure males. We further hypothesised that an increase in male mate competition would result in more call bouts per day and a higher tendency to answer calls, which was not found. Males with a relatively low strength were expected to keep signalling their presence, but because this low strength includes a higher risk for females and infants, we expected females to avoid loud calling extra-group males. Males with a declining strength continued to signal their presence, as was expected, but they did reduce participation in dawn call bouts, which might be a particularly sensitive measure of their decreased strength. Extra-group males answered calls by males during their late tenure phase more often at medium and far distances, which shows that males recognised calls from late tenure males. Females' avoidance of calling extra-group males remained constant during the early and middle phase but increased during the late tenure phase, as was expected. AMB males clearly avoided males from bisexual groups: they never participated in dawn call bouts, they rarely started or answered calls and they travelled away from calling males. AMB males only answered a call bout in the case of a betweengroup conflict, when their position was already known. Hence, in Thomas's langurs, loud call behavior influenced male mate competition, and it varied in relation to changes in relative male strength. [ABSTRACT FROM AUTHOR]

Between-group conflicts are believed to serve two major functions: mate defence and resource defence. In addition, in species where females can disperse, both female choice and male coercion may play a role in between-group interactions. In this paper, I evaluate the resource vs mate defence hypotheses and investigate male and female strategies in between-group interactions in wild Thomas's langurs (Presbytis thomasi). This species lends itself well to study the intertwining of male and female strategies. Thomas's langurs live in one-male multifemale groups; both males and females disperse from their natal groups; female secondary dispersal is also common, and infanticide occurs. The life-span of a group is, as a rule, restricted to the tenure of its reproductive male (median tenure length is 72 months). Male tenure in bisexual groups was divided into three phases: the early phase (no infants yet), the stable middle phase, and the late phase (last year). Because AMBs remained after all females had left a male, they were treated as a fourth phase. I analysed interactions of group members with individuals outside the group using data from a four year field study (1093 observation days) of 15 bisexual and eight all-male groups of Thomas's langurs at Ketambe, Indonesia. Two types of interactions could be distinguished: (1) group encounters: whole groups meet each other, and (2) male provocations: a male silently approaches a group and suddenly attacks the individuals. This study involves 329 group encounters and 265 male provocations. The results support the mate defence hypothesis, but are ambiguous about the role of resource competition: Group encounters during the middle and late tenure phase took place more often in the context 'food patch', than was expected, and they mostly took place in fruit patches, which were a preferred food item. However, the proportion of group encounters that involved aggression did not depend on feeding context or tenure, and fruit availability did not influence group encounter rates. Male aggression during between-group conflicts reflected mate defence, rather than resource defence, although females had the possibility of obtaining resource defence through a male's mate defence. This study suggests that females use the outcome of group encounters and male provocations to assess the relative strength of males, and thus 'chose' a male who is able to defend future offspring. It also suggests that males can use coercion (infanticide and aggression against females) to show the relative weakness of a female's current male and encourage her to transfer: Aggressive behaviour during group encounters was primarily between males. Females only reacted aggressively to extra-group males when their infant was under attack. Male infanticide only occurred during provocations by males from neighbouring groups or AMBs. The intensity of male competition for mates, as measured by male-male aggression and extra-group male interest in a groups' females, was higher during the early and late phases, than during the middle phase of the tenure. It was also higher during the AMB than during the late phase of male tenure. The relative strength of males, as measured by a male's provoking behaviour and his ability to protect his females from aggression by extra-group males, was lower during the late than during the middle tenure phase. Male strength seemed lowest during the subsequent AMB phase. Females avoided extra-group males least during the early tenure phase, before infants were born. [ABSTRACT FROM AUTHOR]

This study examines vigilance as a behavioural indicator of the importance of infanticide risk by comparing the infanticide avoidance hypothesis with the predation avoidance and mate defence hypotheses for wild Thomas's langurs ( Presbytis thomasi) in Sumatra. We found that all individuals were more vigilant in situations of high predation risk, i.e. lower in the trees and in the absence of neighbours. Females were also more vigilant on the periphery of the group. However, there were variations in vigilance levels that could not be accounted for by the predation avoidance hypothesis. Males without infants showed higher levels of vigilance in areas of home range overlap than in non-overlap areas during the early phase of their tenure, strongly suggesting mate defence. In these areas of home range overlap where Thomas's langur groups can interact, males may attack females and infants, and so the infanticide risk for males and females with infants is likely to be high in these areas. Only females with infants, but not males with infants or females without infants, showed higher vigilance levels in overlap areas than in non-overlap areas; in addition, in overlap areas, females with an infant were more vigilant than females without an infant, while this was not the case in non-overlap areas. Both females and males with infants were more vigilant high in the trees than at medium heights in overlap areas but not elsewhere. These findings can only be explained by the infanticide avoidance hypothesis. In contrast to predator attacks, infanticidal male attacks come from high in the canopy, and only occur in overlap areas. There was a significant sex difference in vigilance, but males were only more vigilant than females without an infant, and not more vigilant than females with an infant. We conclude that vigilance varied mainly in relation to the risk of predation and infanticide. Mate competition only played a role for males during the early phase of their tenure. Predation risk seems to offer the best explanation for vigilance for all individuals in the absence of infants. Both predation risk and infanticide risk played a role for females and males with infants. [ABSTRACT FROM AUTHOR]

Presents information on the use of mitochondrial deoxyribonucleic acid (DNA) restriction site polymorphisms analyses among 42 individuals from two Asian leaf monkey species (Trachypithecus auratus and T. Cristatus). Reasons for the use of mitochondrial DNA; Amplification of a 2300-base pair fragment; Reference to a study by (Weitzel and Groves, 1985); Indication of the results.

Investigates the phylogeny of Chinese leaf monkeys, using molecular sequence. Definition of systematic relationships of these species; Sequencing of mitochondrial ND3, ND4L, NDA4, tRNA, tRNA and tRNA genes for Rhinophithecus bieti.

Presents a study of the feeding and ranging behaviors of groups of Presbytis potenziani (langur) in primary forests of North Pagai Island in Mentawi, Indonesia. Habitat; Group composition; Habitat use; Ranging patterns; Group cohesion; Activity patterns; Diet; Forest types and locomotion; Home ranges; Feeding.

Determines the type localities of the gibbon (Hylobates pileatus Gray) and the leaf monkey (Presbytis crepuscula wroughtoni Elliot) in order to complete the nominal primate taxa collected by Alexander Henri Mouhot. Mouhot's sudden death; Mouhot's published itinerary; Evidence from collected specimens.

Studies the group size, composition and habitat of Presbytis francoisi leucocephalus, a white-headed leaf-eating monkey in Hua Shan, Guangxi Zhuang Autonomous Region, China in relation to the white-sideburned (white-cheeked or black) subspecies of presbytis francoisi. Nomenclature and distribution; Methods and site; Results of the findings; Discussion.

Describes the social organization of pigtailed langurs (simias concolor) living in the Pagai Islands, Indonesia, and suggests that any one-male mating system that comprises a mixture of one-female and multifemale groups in the same population be termed monandry. Background and methods; Results; Comparative discussion of data based on previous and present findings; Conclusions.

Female dispersal occurs in a number of primate species. It may be related to: avoidance of inbreeding, reduction in food competition, reduction of predation risk, or avoidance of infanticide in combination with mate choice. Female dispersal was studied for a 5-year period in a wild population of Thomas langurs (Presbytis thomasi ) that lived in one-male multi-female groups. Juvenile and adult individuals of both sexes were seen to disperse. Females appeared to transfer unhindered between groups, mostly from a larger group to a recently formed smaller one. They transferred without their infants and when not pregnant, and seemed to transfer preferentially during periods when extra-group males were harassing their group. During these inter-group encounters extra-group males seemed to try to commit infanticide. Thus, the timing of female transfer was probably closely linked to infanticide avoidance. Moreover, females seemed to transfer when the resident male of their group was no longer a good protector. The observations in the present study suggest that females transferred to reduce the risk of infanticide. Female dispersal may have another ultimate advantage as well, namely inbreeding avoidance. Due to the dispersal of both females and males the social organization of Thomas langurs was rather fluid. New groups were formed when females joined a male; male takeovers were not observed. Bisexual groups had only a limited life span, because all adult females of a bisexual group could emigrate. This pattern of unhindered female dispersal affects male reproductive strategies, and in particular it might lead to infanticidal behavior during inter-group encounters. Am. J. Primatol. 42:179–198, 1997. © 1997 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Presents several abstracts on primatology. Population status of the golden langur (Presbytis geei) in Assam; Vocal communication in Tarsius spectrum; Costs of cooperation in cotton-top tamarins (Saguinus oedipus) in captivity; Theoretical implications of lack of aggression in callitrichids; Others.

The study reports on the use of urinary and fecal hormone measurements for monitoring female reproductive status in captive-housed Hanuman langurs (Presbytis entellus). Matched urine and fecal samples collected throughout 7 complete menstrual cycles of two females, and during part of one pregnancy in a third female were analyzed. Estrone conjugates (E1C) and immunoreactive pregnanediol glucuronide (PdG) in urine and immunoreactive estradiol (E2), progesterone (P4), pregnanediol (Pd) and 20α-hydroxyprogesterone (20αOHP) in feces were measured by enzymeimmunoassay. E1C and PdG in urine were excreted in a cyclic pattern with E1C levels increasing 3- to 4-fold during the follicular phase to reach preovulatory peak values 2 days before a defined rise in PdG concentrations. Cycle lengths ranged between 20 and 34 days comprising a variable follicular phase of 7-21 days and a more consistent luteal phase of 12-14 days. High pressure liquid chromatography (HPLC) analysis of fecal extracts confirmed the presence of all fecal hormones measured, but indicated large amounts of additional immunoreactivity in the three progestin assays. The patterns of excretion of fecal E2 and all three fecal progestins corresponded well with those of steroid metabolites in urine in showing a clear and well defined follicular phase E2 rise followed by a luteal phase progestin increase. Measurement of 20αOHP immunoreactivity revealed the most stable baseline and the highest follicular/luteal phase differential. Levels of all hormones were clearly elevated during pregnancy although urinary E1C and PdG showed a more pronounced increase compared to fecal metabolites. The results indicate that urinary and fecal hormone analysis can be applied to noninvasive monitoring of reproductive status in the Hanuman langur. [ABSTRACT FROM AUTHOR]

Reproductive parameters and sexual behavior of free-ranging Hanuman langurs (Presbytis entellus) were studied over a 13-year period at Jodhpur, India in a population that breeds throughout the year. Long-term monitoring of individually identified females living in one-male-multi-female troops revealed a mean cycle length of 24.1 days (n = 113), a mean gestation of 200.3 days (n = 31), menarche at 29.0 months (n = 10), first conception at 35.0 months (n=12), arid a mean birth interval of 16.7 months (n = 114). The loss of unweaned infants accelerated the resumption of menstruation, receptivity, and attractivity; shortened the period between estrus and next conception; and reduced the median birth interval by 20.5%, thus supporting the sexual selection hypothesis of male infanticide. The decline of fertility with age (as measured by the rates of conception per estrus period), a regular post reproductive survival for up to 9 years (which can account for about 25% of a female's Life span) and indications for the existence of a "true menopause" support the view that a post reproductive period in Langurs is the result of natural selection. There is very limited evidence for situation-dependent receptivity, because only 7.5% of all estrous days (n = 1,037) fell outside of the mid-cycle period with at the same time strongly reduced proceptivity and attractivity. Moreover, posteonception estrus behavior showed a stereotypical pattern during 31 pregnancies and did not reflect a situation-dependent response to the immigration of new and potentially infanticidal males. It is likely that females competed for sperm of the harem holder, because the probability of conception increased significantly with an increase in the number of copulations, and when the number of females copulating on the same day decreased. [ABSTRACT FROM AUTHOR]

Between-group antagonism or territoriality in primates may serve two different but compatible functions: resource defense or mate defense. Females are expected to be involved more strongly in the first, males in the second. The resource defense hypothesis predicts that home range overlap should decrease as defensibility and population density increase, and that females should be involved in hostile between-group interactions. The mate defense hypothesis predicts that between-group relations should be hostile and that males should take the primary role in antagonistic encounters. In a comparative study of 12 populations of 6 Presbytis species in Southeast Asia, we found support for the mate defense hypothesis; only males produce loud calls, between-group antagonism is entirely a male affair, and neither defensibility nor population density determine spatial exclusivity or the level of antagonism. We discuss the differences between our findings and traditional interpretations of territorial behavior. [ABSTRACT FROM AUTHOR]

Predation attempts by cooperatively hunting jackals (Canis aureus) on capped langurs (Presbytis pileata) in moist deciduous forest in north-central Bangladesh are described. The incidents were observed during a 15-m field study of the ecology and behavior of capped langurs. Two attacks on langurs were made cooperatively by, in one instance, a pair and in a second instance a small pack of jackals. One of these attacks was successful. Although P. pileata is a highly arboreal species, both attacks tool place in rare instances of ground travel by the langurs. [ABSTRACT FROM AUTHOR]

During a preliminary study of pig-tailed langurs (Simiacs concolor) in the Pagai Islands, Indonesia, it was discovered that females exhibited conspicuous swelling of the urogenital triangle. The pig-tailed langur is the first Asiatic colobine found to have prominent sexual swellings and the only colobine with sexual swellings that lives in one-male groups. Because all anthropoids with conspicuous sex skin typically live in groups having female-biased adult sex ratios, it is possible that females might compete amongst themselves for the male in one-male groups, or the best males in multimale groups. Sexual swellings may therefore have resulted from sexual selection for signals attractive to makes in female-female competition, as suggested earlier by Bercovitch (California Anthropologist 8:9-12, 1978). Prolonged observation of recognizable individuals will be required to test this hypothesis in the pig-tailed langur and other species. [ABSTRACT FROM AUTHOR]

The rate at which social groups of primates are encountered in disturbed rain forest may be biased relative to undisturbed rain forest. A recently reported case study revealed a 25% reduction in postlogging raw encounter rates even though the true density of primates remained at the prelogging level. If biased raw encounter rates are typical of disturbed forests, and if they translate into equally biased line-transect density estimates, results of many comparative surveys might prove misleading (ie, apparent declines of primates in disturbed forest may not be real). Here a set of line-transect density estimates from logged forest are tested for systematic bias by comparing them to range-mapping density estimates, and the response of a Fourier series detectability function to several hypothetical patterns of bias in raw encounter rates is illustrated. Tests of line-transect density estimates from logged forest provide no evidence of systematic bias. The Fourier series results suggest that biased raw encounter rates may often be ameliorated by line-transect density estimators. Available evidence suggests that line-transect density estimates or similarly transformed encounter rates usually provide reliable comparative results within the limits of a particular study's resolution. In contrast, conclusions drawn directly from comparative raw encounter rates (without transforming them into density estimates) are more prone to error. [ABSTRACT FROM AUTHOR]

Kloss's gibbons (Hylobates klossii) and Mentawai langurs (Presbytis potenziani) on Siberut Island, Indonesia, both sleep in emergent trees 34–55m tall, situated .n crests and upper slopes of hills. They differ in that 91% of gibbon sleeping trees examined were free of lianas, whereas 89% of langur sleeping trees were draped with thick, woody lianas hanging from the branches to the ground. Because indigenous hunters climb lianas to shoot primates in treetops, gibbons are less susceptible than langurs to nocturnal human predation. Hence, the gibbons' preference for—and apparent control of—the limited supply of vineless trees gives them an advantage over langurs. [ABSTRACT FROM AUTHOR]

An investigation of the social rank, reproduction, and ages of adult female Indian gray langur monkeys (Presbytis entellus) living in two colony social groups revealed that rank based on displacements is neither correlated with nor best predicted by female age or reproductive value. The hierarchy of female ranks is best conceptualized as a layered ranking system in which there are clusters of females of the same dominance rank forming layers within the structure. Statistical significance in frequencies of displacement differs between but not within these layered groups of females. Factors such as group composition, presence of uterine kin, reproductive state, and individual personality are hypothesized to predict changes in female rank far better than does reproductive value. Our data show that reproductive success increases with age. The infant survival record for the six oldest females in our colony was much better than for the five youngest adult females. [ABSTRACT FROM AUTHOR]

Presence of spine and sacroiliac involvement and the nature and distribution of the erosive lesions allow definitive diagnosis of Spondyloarthropathy. Thus, Spondyloarthropathy was identified in Theropithecus, Papio, Cercopithecus, Macaca, Colobus, Presbytis, and Hylobates. Only monarticular erosive disease was present in prosimians, precluding a diagnosis of Spondyloarthropathy for that group. The distribution of erosive disease and axial joint involvement in 1,349 non-prosimian Old World primates is quite characteristic of that noted in human psoriatic arthritis. While Reiter's syndrome must also be considered, the histologic appearance of skin lesions in Macaca is characteristic of psoriasis. Evidence of Spondyloarthropathy abounds in the literature of primate skeletal disease. Environmentally based contagions may be important in the pathophysiology of spondyloarthropathy. The wide geographic distribution of the phenomena in monkeys suggests a 'panendemic,' with limited individual susceptibility (compared to that noted in gorillas and chimpanzees). Identical occurrence of erosive arthritis/spondyloarthropathy in free-ranging and artificially restrained animals suggests that spondyloarthropathy can validly be studied in artificially restrained populations. This perspective should allow application of human therapeutic approaches to and perhaps improve the quality of life for artificially restrained, afflicted individuals. © 1992 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Six eye-witness and five inferred cases of infanticide in two troops of Presbytis entellus near Jodhpur, India, are presented. These observations are used to test the hypothesis that infant killing is a male reproductive strategy. [ABSTRACT FROM AUTHOR]

1. An analysis of the factors influencing the reproductive success of infanticidal and noninfanticidal adult males in populations of langur monkeys (Genus Presbytis) is presented. Male tenure, defined as an adult male's length of residency in a one-male bisexual group, is demonstrated to be an important factor in any reproductive advantage accruing to infanticidal males. Other factors include the lengths of the female interconception intervals, the time at which adult male replacement occurs relative to the start of any such interval, and whether or not the subsequent replacement male is also infanticidal. 2. Infanticide is found always to confer a reproductive advantage on the resident male in a bisexual group under conditions of subsequent replacement by a noninfanticidal male. Infanticide would thus be expected to spread when introduced into an otherwise noninfanticidal population. Under conditions of subsequent replacement by an infanticidal male, infanticide is found to be advantageous for the resident male only a particular lengths of tenure. Infanticide would thus become fixed only in populations where the distribution of tenure lengths is advantageous for infanticidal males. Accordingly, it is predicted that average or modal tenure length in populations fixed for infanticide should coincide with those tenure lengths theoretically yielding a reproductive advantage for infanticidal males. Three direct estimates of average male tenure obtained from field studies of langur populations are consistent with the predictions of the model. [ABSTRACT FROM AUTHOR]

Data from a 15-month field study of the capped langur monkey, Presbytis pileata, in Bangladesh indicate that allomothering behavior is restricted to particular female-infant dyads. Primary allomothers were all parous adult females: nulliparous females rarely allo-mothered, Newborn infants were transferred from the mother to other females within a short time of birth, as reported for some other colobine species, but over the first 3 months of life each neonate's contact with nonmothers was largely restricted to a single allomother in each of five study groups. Capped langur mothers with newborn infants spent more time feeding when the infant was being allomothered than when it was in the mother's care. The model of allomothering as a selfish behavior by nulliparous or pregnant females used to enhance maternal skills at the expense of mothers is not supported by this study. Rather, allomothering may have adaptive significance as altruistic behavior among group females, in that it enables lactating females to increase feeding time. Capped langur allomothering is best interpreted as a low-cost behavior that can benefit recipients that may or may not be related. [ABSTRACT FROM AUTHOR]

A birth during the day by a capped langur ( Trachypithecus pileatus Blyth, 1843) was recorded at Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. The birth took 43 min. Allomothering was observed 3 h after the birth. An average of 9% of daily active time was shared by four allomothers (three adults, one subadult) during the first 15 days of the infant’s life. Total time allomothering was proportional to the age of the allomothers (241 min for oldest; 214 min for youngest). [ABSTRACT FROM AUTHOR]