Distribution and Abundance of Primates in Rain Forests of the Western Ghats,Karnataka, India and the Conservation of Macaca silenus

We assessed the distribution and abundance of 4 species of diurnal primates viz. lion-tailed macaque, bonnet macaque, Nilgiri langur and Hanuman langur, in 2 areas—Brahmagiri-Makut and Sirsi-Honnavara—in rain forests of the Western Ghats in the state of Karnataka, India. The Nilgiri langurs in Brahmagiri-Makut and the lion-tailed macaques in Sirsi-Honnavara are the northernmost populations of the 2 species in the Western Ghats. The 2 regions represent changes in ecological zones in the Western Ghats. In Brahmagiri-Makut, Hanuman langurs and bonnet macaques occupy lower elevations whereas Nilgiri langurs live in relatively higher altitudes. Only one group of lion-tailed macaques was in Brahmagiri-Makut. In the forests of Sirsi-Honnavara, 3 species of primates viz. lion-tailed macaque, bonnet macaque and Hanuman langur were in larger numbers throughout the forest. A self-sustainable single population of 32 groups of lion-tailed macaques occurred in Sirsi-Honnavara. Few subspecies of Hanuman langurs exist in the study regions. Due to local hunting practices, the relative abundance of primates in Brahmagiri-Makut is lower than that in Sirsi-Honnavara.     

Gut microbiome,diet, and conservation of endangered langurs in Sri Lanka

Understanding the mechanisms by which organisms respond to environmental change is critical to conservation biology. Recent research indicates that the gut microbiome may mediate mammalian responses to the environment and can be used as a biomarker to understand host ecological strategies. Here, we explore the relationship between the gut microbiome, host dietary niche, and potential resilience to habitat alteration using two closely related, sympatric non-human primate species: the tufted gray langur (Semnopithecus priam) and the purple-faced langur (Semnopithecus vetulus). The gray langur is suspected to be a habitat generalist less perturbed by anthropogenic disturbance, while the purple-faced langur is suspected to be a specialist more sensitive to disturbance. To test these characterizations, we assessed the gut microbiome using 16S rRNA gene amplicon sequencing of fecal samples collected from Kaludiyapokuna Forest Reserve, Sri Lanka (gray langur n = 50 samples, purple-faced langur n = 7 samples). Our results demonstrate that despite strong gut microbial similarities, gray langurs had a more diverse gut microbiome that harbored Prevotella and Akkermansia, taxa involved in starch degradation, while the purple-faced langur gut microbiome harbored Roseburia, Clostridium, and Ruminococcus, taxa involved in processing plant structural carbohydrates. Compared to related species in other locations, both Sri Lankan langurs harbored more pathogenic bacteria. These differences suggest that gray langurs have more generalist diets, making them more resilient to anthropogenic change, but also indicate that they are not impervious to human encroachment. Our findings suggest that microbiome analyses are an important tool for langur ecology and conservation, and should be integrated into ongoing studies.     

Mitochondrial and nuclear markers suggest Hanuman langur (Primates: Colobinae) polyphyly: Implications for their species status

Recent molecular studies on langurs of the Indian subcontinent suggest that the widely-distributed and morphologically variable Hanuman langurs (Semnopithecus entellus) are polyphyletic with respect to Nilgiri and purple-faced langurs. To further investigate this scenario, we have analyzed additional sequences of mitochondrial cytochrome b as well as nuclear protamine P1 genes from these species. The results confirm Hanuman langur polyphyly in the mitochondrial tree and the nuclear markers suggest that the Hanuman langurs share protamine P1 alleles with Nilgiri and purple-faced langurs. We recommend provisional splitting of the so-called Hanuman langurs into three species such that the taxonomy is consistent with their evolutionary relationships.     

Molecular phylogeny and biogeography of langurs and leaf monkeys of South Asia (Primates: Colobinae)

The two recently proposed taxonomies of the langurs and leaf monkeys (Subfamily Colobinae) provide different implications to our understanding of the evolution of Nilgiri and purple-faced langurs. Groves (2001) [Groves, C.P., 2001. Primate Taxonomy. Smithsonian Institute Press, Washington], placed Nilgiri and purple-faced langurs in the genus Trachypithecus, thereby suggesting disjunct distribution of the genus Trachypithecus. [Brandon-Jones, D., Eudey, A.A., Geissmann, T., Groves, C.P., Melnick, D.J., Morales, J.C., Shekelle, M., Stewart, C.-B., 2003. Asian primate classification. Int. J. Primatol. 25, 97-162] placed these langurs in the genus Semnopithecus, which suggests convergence of morphological characters in Nilgiri and purple-faced langurs with Trachypithecus. To test these scenarios, we sequenced and analyzed the mitochondrial cytochrome b gene and two nuclear DNA-encoded genes, lysozyme and protamine P1, from a variety of colobine species. All three markers support the clustering of Nilgiri and purple-faced langurs with Hanuman langur (Semnopithecus), while leaf monkeys of Southeast Asian (Trachypithecus) form a distinct clade. The phylogenetic position of capped and golden leaf monkeys is still unresolved. It is likely that this species group might have evolved due to past hybridization between Semnopithecus and Trachypithecus clades.     

Molecular systematics and conservation of the langurs and leaf monkeys of South Asia

Numerous morphology-based classification schemes have been proposed for langurs and leaf monkeys of South Asia but there is very little agreement between them. An incorrect classification scheme when used as a basis for biogeographic studies can support erroneous hypotheses. Further, lack of taxonomic resolution will also confound conservation efforts, given that conservation biologists use traditional morphology-based-classification schemes to prioritize species for conservation. Here, I have revisited recent molecular phylogenetic studies done on langurs and leaf monkeys of South Asia. Results from these studies are in turn used to derive a rational and scientific basis for prioritizing species for conservation. Molecular data support the classification of langurs of the Indian subcontinent—Hanuman, Nilgiri and purple-faced langurs—in the genus Semnopithecus, whereas Phayre’s leaf monkey along with other Southeast Asian leaf monkeys form another distinct clade (Trachypithecus). The phylogenetic position of capped and golden langurs remains unresolved. Molecular data suggest that they are closely related to each other but this group might have evolved through past hybridization between Semnopithecus and Trachypithecus. Additionally, genetic data also support the splitting of the so-called Hanuman langurs into at least three species. The scores for taxonomic uniqueness of langurs and leaf monkeys of South Asia were revised using this molecular phylogeny-based classification. According to the revised scores, Phayres leaf monkey and golden langur are priority species for conservation followed by capped and Nilgiri langurs.     

Of how much concern are the ‘least concern’ species? Distribution and conservation status of bonnet macaques,rhesus macaques and Hanuman langurs in Karnataka,India

We assessed the distribution and conservation status of bonnet macaques (Macaca radiata), rhesus macaques (Macaca mulatta) and Hanuman langurs (Semnopithecus entellus) in the state of Karnataka, India. Karnataka is situated in southwest India with an area of 191,791 km². A total of 9697 km of vehicular survey was made from November 2001 to July 2004. We also visited 107 temples/tourist spots to determine the presence of primates. Bonnet macaques and Hanuman langurs were widely distributed, whereas rhesus macaques were not found in the state. However, bonnet macaques were absent in a few districts in the northern plains and Hanuman langurs were absent in some districts of the southern plains. A total of 205 groups of bonnet macaques and 139 groups of Hanuman langurs were sighted. The relative encounter rate of both species differed across biogeographic zones. Bonnet macaques were largely encountered in the Western Ghats and the Southern Plateau whereas Hanuman langurs were abundant in the Western Ghats and Northern Plains. We found that bonnet macaques have been eliminated from about 48% temples/tourist spots where they occurred in the recent past. The Hanuman langur population of Dharwar–Haliyal Road was assessed during April 2003, and we found that the present population size was about 38% of a previous survey in 1961. Habitat change, hunting/trapping and translocation were the major factors causing a decline in the langur population.     

中国石山叶猴生态学研究进展

喀斯特石山是一类特殊环境,生存在喀斯特石山的动物形成特殊的行为机制以适应这一特殊的环境.石山叶猴是仅分布于喀斯特石山地区的珍稀濒危灵长类动物,属疣猴亚科乌叶猴属的一个种组,包括黑叶猴(Trachypithecus francoisi)、白头叶猴(T.leucocephalus)、德氏叶猴(T.delacouri)、金头...     

The Emergence of an Endangered Species: Evolution and Phylogeny of the <Emphasis Type="Italic">Trachypithecus geei</Emphasis> of Bhutan

Golden langurs (Trachypithecus geei) are an endangered primate species in Bhutan. We discuss their evolution in terms of phylogeny, ecology, and biogeography. We test the hypothesis that rivers and mountains in Bhutan isolated a population of capped langurs (Trachypithecus pileatus) that later speciated into the morphologically distinct T. geei. Trachypithecus, the genus to which both capped and golden langurs belong, spread north from a paleorefuge in south China, and Semnopithecus (gray langurs) spread east and northward from a refuge in south India. We show that the 2 genera both arrived in Bhutan and were separated from each other by the Sunkosh River and Black Mountains. Likewise, a population of capped langurs isolated from parental populations by rivers speciated into the distinct golden langurs. We conducted field surveys covering the entire range of langurs in Bhutan. The Sunkosh River and Black Mountain range in west Bhutan isolate gray langurs and golden langurs from each other. In the east, the Manas River system (Manas-Mangde) served as a barrier between golden and capped langurs. However, it is an imperfect barrier and a contact zone between the 2 species occurred on the banks of the Mangde River. Second, we reconstructed the evolutionary history of the langurs of Bhutan via molecular phylogenetic tools. We sequenced the cytochrome b region (cyt b) of the mitochondrial DNA (mtDNA) to model a phylogeny. It revealed the distinct evolutionary paths of the golden, capped, and gray langurs. As predicted, golden and capped langurs are closely related to each other and to other species in Trachypithecus from Southeast Asia. The gray langur of Bhutan grouped into a distinct clade with conspecifics in Semnopithecus from India and Nepal. The south Indian clade of gray langurs is more ancient, with the Bhutan and Nepal gray langurs having diverged later, which fits with the glacial models of ice sheet retreats and colonization of South Asia by gray langurs from south India north toward the Himalayas. Likewise, the golden and capped langur clade are the most derived and divergent from the older groups of Trachypithecus in Southeast Asia, which also fits with paleorefuge models of recolonization by Trachypithecus into the rest of Southeast Asia and north toward the Himalayas from paleorefuges in Southeast Asia. As predicted, golden and capped langurs are closely related to each other and gray langurs are only distantly related to them. The divergence between capped and golden langurs is more recent, while the split between Trachypithecus and Semnopithecus is more ancient and took place before the Pliocene.     

Variation of hamstrings lengths and velocities with walking speed

Crouch gait, one of the most prevalent movement abnormalities among children with cerebral palsy, is frequently treated with surgical lengthening of the hamstrings. To assist in surgical planning many clinical centers use musculoskeletal modeling to help determine if a patient’s hamstrings are shorter or lengthen more slowly than during unimpaired gait. However, some subjects with crouch gait walk slowly, and gait speed may affect peak hamstring lengths and lengthening velocities. The purpose of this study was to evaluate the effects of walking speed on hamstrings lengths and velocities in a group of unimpaired subjects over a large range of speeds and to determine if evaluating subjects with crouch gait using speed matched controls alters subjects’ characterization as having “short” or “slow” hamstrings. We examined 39 unimpaired subjects who walked at five different speeds. These subjects served as speed-matched controls for comparison to 74 subjects with cerebral palsy who walked in crouch gait. Our analysis revealed that peak hamstrings length and peak lengthening velocity in unimpaired subjects increased significantly with increasing walking speed. Fewer subjects with cerebral palsy were categorized as having hamstrings that were “short” (31/74) or “slow” (38/74) using a speed-matched control protocol compared to a non-speed-matched protocol (35/74 “short”, 47/74 “slow”). Evaluation of patients with cerebral palsy using speed-matched controls alters and may improve selection of patients for hamstrings lengthening procedures.     

How does the white-headed langur (Trachypithecus leucocephalus) adapt locomotor behavior to its unique limestone hill habitat?

Limestone hill habitats pose unique challenges to langurs. One of the characteristics of this habitat is its cliffs, which account for about 10–20% of the total area. We have never observed langurs falling from the cliffs during our 10-year field study. Five patterns of locomotion were exhibited by the white-headed langur: (1) arboreal ascent and descent, (2) arboreal quadupedalism, (3) terrestrial quadrupadelism, (4) moving on cliffs and (5) leaping on cliffs. Locomotor patterns varied according to the substrate, but terrestrial quadrupedalism accounted for more than 50% of locomotion time. Moving on cliffs and leaping on cliffs may be modes of locomotion unique to the white-headed langur, at least in terms of frequency. White-headed langurs have an intermembral index of 76 and, compared to langurs with a similar intermembral index, are more terrestrial. Further analysis indicates that greater terrestrialism may be the result of adaptation to their limestone habitat. Interestingly, white-headed langurs select caves on the cliff as their sleeping sites, and they exhibit special behaviors for exiting and entering the cave very early in the morning and late in the evening.     

Gaits of Japanese macaques (Macaca fuscata) on a horizontal ladder and arboreal stability

Most primates use diagonal sequence (DS), diagonal couplets (DC) gaits when they walk or run quadrupedally, and it has been suggested that DSDC gaits contribute to stability in their natural arboreal habitats compared to other symmetrical gaits. However, this postulate is based solely on studies of primate gaits using continuous terrestrial and arboreal substrates. A particular species may select suitable gaits according to the substrate properties. Here, we analyzed the gaits of Japanese macaques moving on a horizontal ladder with rung intervals ranging from 0.40 to 0.80 m to elucidate the relative advantages of each observed form of gait. The rung arrangement forced our macaques to choose either diagonal coupling or DS gaits. One macaque consistently used diagonal coupling (i.e., DSDC and LSDC gaits) across narrow and intermediate rung intervals, whereas the other macaque used DS gaits (i.e., DSDC and DSLC gaits). At wider rung intervals, both macaques shifted to a two‐one sequence (TOS), which is characterized by two nearly simultaneous touchdowns of both forelimbs and one touchdown of each hind limb in a stride. The transition to the TOS sequence increased the duration of support on multiple limbs, but always included periods of a whole‐body aerial phase. These results suggest that Japanese macaques prefer DSDC gaits, because the diagonal coupling and DS contribute separately to stability on complex supports compared to the lateral coupling and lateral sequence. We also postulate that stability triggers the transition from symmetrical gaits to the TOS sequence. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.     

Food diversity and choice of white-headed langur in fragmented limestone hill habitat in Guangxi,China

We studied the diet and food choice of three groups of white-headed langurs (Trachypithecus leucocephalus) from July 2002 to June 2003 at Fusui Rare Animal Reserve, Guangxi, China. Data were collected from via focus group sampling, with continuous recording. A total of 109 plant species (including 19 unidentified species) were used as food by the white-headed langur. They spent 91.6% of total feeding time feeding on leaves, 4.2% on fruits and 3.3% on stems. Flowers and other food items accounted for only 0.3% and 0.6% of total feeding time, respectively. There were significant seasonal variations in the langurs’ diets with changes in the total number of species and the diversity of food species consumed. The langurs used significantly more plant species as food in the rainy season than in the dry season (36 species vs. 26.5 species). Dietary diversity was also significantly higher in the rainy season than in the dry season (2.6 vs. 2.4). No significant seasonal variation was found in the percentage of various plant parts in their monthly diets. Though the white-headed langur fed on many plant species, 11 species made up 84.9% of their diet. There were no significant correlations between the percentage of feeding time for main food plant species and their corresponding abundance in the habitat, content of water, crude protein, crude fiber and the ratio of crude protein to crude fiber. These results suggest that food choice of the white-headed langur is not influenced by their abundance and nutritional content.     

Positional behavior of free-ranging Japanese macaques (<Emphasis Type="Italic">Macaca fuscata</Emphasis>)

Positional behavior was quantitatively studied in identified free-ranging Japanese macaques (Macaca fuscata). Five male and 11 female adults were observed in a forested mountain habitat. Data were analyzed for proportion of bout distance, number and time of each locomotion and postural type. Japanese macaques are semiterrestrial, and mainly walk and run quadrupedally. This supports the notion that Macaca are generally quadrupeds. Sex differences in positional behavior were found in the preference of substrate and types of positional behavior. Males and females tend to be terrestrial and arboreal, respectively. Males leap more frequently and longer in distance than do females when they are feeding in trees. These sex differences are considered to be related to differences in morphology, food choice, social activity, and the nursing of infants. Frequencies of leaping and the distance covered by leaping in Japanese macaques are more than those of long-tailed macaques which are arboreal quadrupeds. However, Japanese macaques leap shorter distances at a time than do long-tailed macaques, which indicates that body size may be related to leaping distance more than the frequency of leaping and the distance covered by leaping. Japanese macaques are not as specialized for terrestrial locomotion as pig-tailed macaques. They use both terrestrial and arboreal supports, and are considered to be semi-terrestrial quadrupeds, somewhere between the arboreal long-tailed macaque and the terrestrial pig-tailed macaque. Electronic Publication     

Infanticide as an alternative male reproductive strategy in langurs: A mathematical model

This paper makes explicit some of the assumptions underlying the view that infanticide is one of two (or more) alternative reproductive strategies utilized by adult male langur monkeys (genus Presbytis). A mathematical model has been developed from these assumptions, and formulae derived which give the equilibrium proportion of infanticidal males expected in langur populations under any given set of reproductive and demographic conditions. Together with estimates of adult male reproductive success obtained from a previous analysis of langur infanticide, these formulae were then used to calculate the precise proportion of infanticidal males expected in natural populations of langurs characterized by specific average male tenures. Further, the number of generations required for such populations to reach their predicted equilibrium was estimated using a simple computer model of langur population dynamics. The present work has thus produced several quantitative predictions which are directly falsifiable with observational data obtainable from wild populations of langur monkeys. With only slight modification, the present model may also be applied to the numerous other primate and non-primate species whose mating systems include many of the same general features as that of langurs.     

The morphological basis of the underbite trait in langurs (P. melalophus and T. cristatus) with an analysis of adaptive and evolutionary implications

Underbites or mandibular incisor protrusions are widely prevalent among Coloboid monkeys. The morphological basis of the trait is explored in two langur species differing with respect to its incidence. P. melalophus, characterized by a high occurrence of underbites, has mandibular incisors which are significantly wider than those of T. cristatus, the more “normative” occlusal group. No other statistically significant incisor metric differences are noted. Comparisons of convexgent traits in the Colobinae, Alouattinae, and Ruminantia support the contention that underbites are a herbivorous adaptation. The zoogeographic distribution of the trait in langurs is discussed in the context of evolutionary dynamics.     

Measuring fruit patch size for three sympatric indonesian primate species

Food availability is one of the basic factors affecting primate density and socioecology, but food availability is difficult to assess. Two different ways to obtain accurate estimates of food availability have been proposed: using phenology data or using the behaviour of animals. Phenology data can be refined by only including trees that are large enough to be used; including (potential) tree species in which by the concerned primate species forage; or including (fruiting) trees of these species that actually produce fruit. Alternatively, the sizes of the actually visited trees (foraging trees) give an estimate of fruit availability. These measures are compared for three sympatric primate species at the Ketambe Research Station, Sumatra, Indonesia: the Thomas langur, the long-tailed macaque and the orangutan. The sizes of fruiting trees and the foraging trees are larger than the potential trees. The sizes of the potential trees and of the fruiting trees are similar for the three primate species. This, however, is not reflected in the use of trees: the langurs forage on average in trees of similar size to those producing fruit, whereas the macaques and orangutans forage in trees larger than those producing fruit. The use of trees does not necessitate a different cut off point of included dbhs for the three compared primate species. The use of trees of different sizes, however, may be regulated by food competition. This indicates that sympatric primates make different foraging decisions and that behavioural measures of food availability will be less reliable.     

Do highly trained monkeys walk like humans? A kinematic study of bipedal locomotion in bipedally trained Japanese macaques

In this study, we examined the kinematics of bipedal walking in macaque monkeys that have been highly trained to stand and walk bipedally, and compared them to the kinematics of bipedal walking in ordinary macaques. The results revealed that the trained macaques walked with longer and less frequent strides than ordinary subjects. In addition, they appear to have used inverted pendulum mechanics during bipedal walking, which resulted in an efficient exchange of potential and kinetic energy. These gait characteristics resulted from the relatively more extended hindlimb joints of the trained macaques. By contrast, the body of the ordinary macaques translated downward during the single-limb stance phase due to more flexed hindlimb joints. This resulted in almost in-phase fluctuations of potential and kinetic energy, which indicated that energy transformation was less efficient in the ordinary macaques. The findings provide two insights into the early stage of the evolution of human bipedalism. First, the finding that training considerably improved bipedal walking a posteriori may explain why the very first bipeds that might not yet have been morphologically adapted to bipedal walking continued to walk bipedally. The evolutionary transition from quadrupedalism to bipedalism might not be as difficult as has been envisioned. In addition, the finding that macaques, which are phylogenetically distant from humans and in which bipedal walking is unlike human walking, could develop humanlike gait characteristics with training, provides strong support for the commonly held but unproven idea that the characteristics of the human gait are advantageous to human bipedalism.     

白头叶猴与黑叶猴觅食行为的比较

开展近缘物种觅食行为比较对理解动物的行为可塑性及适应性具有重要意义。白头叶猴(Trachypithecus leucocephalus)和黑叶猴(T.francoisi)是近缘物种,体形大小相近,社会结构和栖息环境相似,是广西崇左白头叶猴国家级自然保护区喀斯特季节性雨林中邻域分布的灵长类。为了探索两个物种在喀斯特生境中是否有相似的觅食策略,我们于2012年1—12月采用瞬时扫描取样法对两种叶猴的觅食行为进行研究。结果表明,白头叶猴与黑叶猴在不同时段均为叶食性,树叶是两种叶猴各个时段主要食物,其中白头叶猴日均取食树叶77.0%±4.4%,黑叶猴日均取食68.9%±8.3%,两者对树叶的采食比例均没有显著的日时段差异(白头叶猴:χ²=6.602,df=11,P=0.830;黑叶猴:χ²=11.393,df=11,P=0.411)。两种叶猴的觅食行为都在猴群清晨离开夜宿石洞后和进入过夜山洞前的时段中频繁发生。白头叶猴在09:00—10:59和16:00—17:59出现觅食高峰,时间占比分别为41.7%和46.3%;黑叶猴同样在09:00—10:59...     

Factors Influencing Interannual and Intersite Variability in the Diet of <Emphasis Type="Italic">Trachypithecus francoisi</Emphasis>

Comparative studies of the diet of the same species in different habitats, and over the long term, are essential to understanding a species’ behavioral and ecological plasticity. Moreover, such studies can help researchers and managers evaluate a species’ capacity to cope with changes in habitat quality resulting from natural processes or human disturbance, which is important for developing conservation strategies. We compared dietary data for François’ langur (Trachypithecus francoisi) collected at Nonggang and Fusui Nature Reserves, Guangxi Province, China, over 2 separate study periods to evaluate interannual and intersite variation in diet. Young leaves were the preferred staple foods for langurs, whereas mature leaves and seeds served as fallback foods in response to seasonal shortage in the abundance of young leaves. Species composition of the diets and the percentage of feeding records for plant species varied between the 2 study periods. The langurs at both study sites fed selectively, and they did not base their diet simply on the abundance of plant species in the habitat. However, the plant species eaten by langur groups inhabiting the 2 different reserves were markedly different, and the top 10 food species eaten by the Fusui group showed no overlap with those eaten by the Nonggang group. The variation may be related to differences in forest composition resulting from different level of human disturbance. In summary, our results indicate that François’ langurs exhibit a comparable dietary pattern both temporally and geographically, but there is marked interannual and intersite difference in species composition of the langur diet.