Purple-faced Langur Research Articles

Utilization of home garden crops by primates and current status of human-primate interface at Galigamuwa Divisional Secretariat Division in Kegalle District, Sri Lanka

Many humans coexist with non-human primates (NHP), and as human populations have increased so have the pressures on natural habitats. For example, deforestation results in habitat loss and food scarcity for NHPs. In response, NHPs sometimes enter human habitats in search of food, which can result in negative interactions between humans and NHPs. This study focused on human-NHP interactions in three Grama Niladhari divisions in Kegalle District, Sri Lanka. We used interviewer-administered structured questionnaires to collect data from 500 randomly selected informants. The majority stated that they could not obtain sufficient harvests from home gardens for their own consumption owing to crop damage and losses caused largely by NHPs and other wild animals. This has led many people to abandon home gardening. Toque Macaques caused the most damage to crops, followed by Wild Boars, porcupines, and Purple-faced Leaf Langurs. Damage was caused to coconuts, vegetables, bananas, and yams. NHPs also caused property damage, with Toque Macaques causing more damage than langurs. People commonly used firecrackers, catapults and air rifles, and wore wooden or plastic face masks, in attempts to control crop damage by NHPs, with little success. People are of the opinion that the NHPs should be relocated to other forested areas or sterilized to control their numbers. In conclusion, to address the issues pertaining to human-primate interactions in terms of conflict due to crop utilization of primates, an integrated management plan should be developed in cooperation with the relevant stakeholders.

A RETROSPECTIVE STUDY OF MORBIDITY AND MORTALITY IDENTIFIED AT POSTMORTEM EXAMINATION OF CAPTIVE LANGURS (TRACHYPITHECUS SPP) FROM SIX UNITED KINGDOM ZOOLOGICAL INSTITUTIONS: A 19-YEAR REVIEW.

Langurs are Asian primates belonging to the Colobinae subfamily. Langur populations are declining, with most species categorized as threatened by the International Union for Conservation of Nature. Investigation into the threats to population viability and sustainability would be beneficial but there is limited literature available on common diseases or causes of death in these species, either in captive or free-ranging settings. This study aimed to evaluate the most common causes of morbidity and mortality in Trachypithecus species submitted for postmortem examination by six United Kingdom zoological institutions between 2001 and 2020, to inform best practice husbandry guidelines. Necropsy and histopathology reports from 88 individuals of Trachypithecus species from six zoological organizations in the United Kingdom were analyzed. Species included Javan langurs (Trachypithecus auratus; n = 35), dusky langurs (Trachypithecus obscurus; n = 28), François' langurs (Trachypithecus francoisi; n = 16), purple-faced langurs (Trachypithecus vetulus; n = 4), silvered langurs (Trachypithecus cristatus; n = 4), and Phayre's langur (Trachypithecus phayrei; n = 1). Morbidities and causes of death were recorded. Gastrointestinal diseases and systemic infections were the leading causes of death (27.4% and 21.0% of cases where cause of death was known, respectively); linear foreign bodies were the most common cause of death. Interstitial pneumonia was frequently observed secondary to systemic infection. Heart abnormalities, anthracosis, and hemosiderosis were common but not directly associated with mortality. Further investigation is necessary to assess the importance of these conditions and whether they predispose to other diseases. This study provides a baseline for future research evaluating captive and free-ranging langur health and highlights husbandry practices that may decrease morbidity in these species.

Assessment of crop and property damage caused by Semnopithecus vetulus nestor (Bennett, 1833) (Mammalia: Primates: Cercopithecidae) in Gampaha District, Sri Lanka

In earlier times, human-monkey interactions were not a severe problem in Sri Lanka, but has recently intensified as a result of habitat fragmentation and urbanization. Due to these changes, Semnopithecus vetulus nestor has been listed among the 25 most Endangered primates. The objective of our study was to evaluate the intensity of human-S.v. nestor negative interaction by identifying the crop and property damages in villages bordering Danawkanda Forest (7.001N & 80.049E), Gampaha, Sri Lanka. We collected data using structured questionnaires interviewing households (N= 80) bordering the Danawkanda Forest from August 2014 to January 2015. Households were most affected by damage to fruits, leaves, and buds of commercially important trees (93%), followed by damage to roof tiles (76%), and frightful confrontations with the monkeys (43%). Average monthly loss per household from crop and property damage was estimated at between (Sri Lankan Rupees) LKR 2,700 and LKR 1,500. Lighting firecrackers was the most common method used by the residents (99%) to deter monkeys, where as electrified barriers were rarely used (4%). Households in close proximity to Danawkanda Forest experienced a considerable loss to their monthly income due to crop and property damage, compared to households further away. As an alternative, residents now grow ornamental plants and short trees, eliminating the structures that attract and facilitate damage by S.v. nestor. Awareness and active participation of residents, authorized government, and non-governmental organizations are needed to manage unplanned construction and agriculture plot extensions into the forest. These two factors trigger the human-wildlife negative interactions in general and are not limited just to monkeys.

Gastrointestinal parasites of endemic and endangered free-ranging purple-faced leaf monkey (Semnopithecus vetulus) in Sri Lanka: effect of host group size and habitat type.

Similar infectious agents may be shared among human and nonhuman primates due to their close proximity. Gastrointestinal parasitism is one of the main diseases which can be transmitted between human and nonhuman primates. It is vital to understand the potential transmissions of gastrointestinal parasites (GIP) and monitor their prevalence in free-ranging populations. This study was carried out to determine the prevalence and diversity of the GIP of Semnopithecus vetulus in Sri Lanka from December 2017 to April 2019. Fresh fecal samples (N = 78) were collected and analyzed using fecal floatation technique and direct iodine mounts. Of these, 55% contained at least one species of GIP (helminths: N = 18 protozoans: N = 30). Multiple infections were recorded in 12% of the samples testing positive for parasites. The most prevalent helminth was Trichuris trichiura (15%). A significant relationship was found between the prevalence of T. trichiura and troop size. There were also significant differences in the prevalence of T. trichiura and Ascaris lumbricoides with habitat type. Compared to the forest dwelling populations sampled, those dwelling in urban and suburban habitats receive higher solar radiation, daytime temperatures and disturbance from humans. These conditions can be expected to influence GIP infection rates. S. vetulus living in continuously degrading habitats face a significant threat from GIP infections. Continuous and improved parasitological surveillance is needed to help monitor the conservation status of wildlife and to secure human health.

Mixed-species associations and attempted mating suggest hybridization between purple-faced and tufted gray langurs of Sri Lanka.

Hybridization is increasingly recognized as an important mechanism of evolutionary change in the order Primates. Here, we present the first observational data supporting natural hybridization between the critically endangered purple-faced langur (Semnopithecus vetulus philbricki) and the threatened tufted gray langur (Semnopithecus priam thersites) in Kaludiyapokuna Forest Reserve in Sri Lanka. In one case study, we observed a long-term (> 1 year) mixed-species group consisting of one adult tufted gray langur male coexisting with seven adult purple-faced females. Although copulations were not observed, two infants were conceived during the male’s tenure, and the coat color of one of these infants transitioned into that intermediate between those of the two langur species. The tufted gray langur male was also aggressive toward extra-group males of both species, as well as towards purple-faced juveniles within his group. However, we never witnessed the male exhibiting aggression towards the infants conceived during his tenure. In a second case study, a female purple-faced langur visited and sexually solicited a tufted gray langur male in a known study group of this species over the course of 2 days, in what resembled a sexual consortship. Taken together, the observed mixed-species association and attempted interspecific mating suggest that hybridization is very likely in these sympatric species. Genetic data are needed to confirm and determine the extent of hybridization in the dry zone of Sri Lanka where purple-faced langurs live in sympatry with tufted gray langurs.

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

AbstractUnderstanding 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.

Study on Home Range Size and Pattern Among Three Diurnal Non-Human Primates in Mihintale Wildlife Sanctuary in Sri Lanka

The size and pattern of a primate home range depends basically on the availability of distribution of food, the density of the group, free-ranging species and geographical factors. When considering about Sri Lankan primates; Sri Lanka is home to five primate species. Three species belongs to catarrhines, the toque monkey (Macaca sinica), the purple-faced langur (S. vetulus), the grey langur (S. priam thersites) and two or more species of the slender loris (Loris spp.). This study was conducted in Mihinthale wildlife sanctuary and focused on the home range of the toque monkey (Macaca sinica sinica), the purple-faced leaf langur (S. vetulus philbrick), and the grey langur (S. priam thersites). Preliminary observations were started from January 2015 to May of 2015. Intensive data collection was started from May 2015 to September, 2016. Behavioural observations were conducted for 136 days. Three groups were selected randomly to represent all three species for this long term study. Home range data was collected by observations of daily path range of the three species. To determine the actual home range of the three species GPS points and hard copies of maps of the site were used. GIS maps were created to illustrate the area used by each species. The results of the home range sizes of each species indicated that the purple-faced –leaf langur’s home range is the largest among the three species. All macaque groups have a minimum home range when compare with the other two langur species. Macaques mainly depend on human-supplied food and hardly depend on the food from the forest, hence recording the smallest home range among the three primate species. The study concludes that purple - faced leaf langur’s home range is the largest home range than gray langur and toque macaque. Gray langur’s home range is larger than toque macaques and smaller than purple-faced leaf langur. Toque macaque has the smallest home range. The identified two main factors for this difference are the availability of food and the density of groups in the given area. KEYWORDS: food availability, group size, Diurnal, Primate, Home Range

Retention marker excretion suggests incomplete digesta mixing across the order primates

The digestive tract of animals, and the patterns how passage markers are excreted from them, have been fruitfully compared to chemical reactor models from engineering science. An important characteristic of idealized reactor models is the smoothness of the curves plotting marker concentrations in outflow (i.e., faeces) over time, which is the result of the assumed complete mixing of the marker with the reactor contents. Published excretion patterns from passage experiments in non-primate mammals appear to indicate a high degree of digesta mixing. In order to assess whether marker excretion graphs from primates differ from ideal outflow graphs, we performed passage experiments in eight individuals of three foregut-fermenting species (Pygathrix nemaeus, Trachypithecus auratus and Semnopithecus vetulus), and added them to available marker excretion curves from the literature. In the resulting collection, 23 out of a total of 25 patterns in foregut fermenters (21 individuals of 10 species from 7 studies), and 13 out of 15 in hindgut fermenters (9 individuals of 2 species from 2 studies), showed an irregular, ‘spiky’ pattern. We consider this proportion to be too high to be explained by experimental errors, and suggest that this may indicate a taxon-wide characteristic of particularly incomplete digesta mixing, acknowledging that further data from less related primate species are required for corroboration. Our hypothesis is in accordance with previous findings of a comparatively low degree of ‘digesta washing’ (differential retention of particulate and fluid digesta) in primates. Together with literature findings that suggest a low chewing efficiency in primates compared to other mammals, these observations indicate that in contrast to other herbivores, the success of the primate order is not derived from particularly elaborate adaptations of their ingestive and digestive physiology.

A potential habitat corridor for Western Purple-faced Langur between Forest Reserves in Sri Lanka: GIS as a tool in connectivity modelling

Endemic Western purple-faced langur (Semnophithecus vetulus nestor) of Sri Lanka, is an exclusively arboreal, critically endangered primate whose habitats are severely fragmented with the human population expansion. Labugama-Kalatuwawa Forest Reserve (LKFR) which is identified as the last strongholds for maintaining viable populations of the species over the long-run and Indikada Mukalana Forest Reserve (IMFR) which is located in a closer proximity to LKFR have no connection with each other at the current status. As there is no assertion of regional habitat connectivity at a metapopulation context, the study aimed to identify a potential habitat corridor for S. v. nestor between LKFR and IMFR by using GIS as a tool in connectivity modelling. Study area was first divided into 0.04 km2 grids using ‘fishnet’ tool. Five main resistance criteria for S. v. nestor movement were selected namely; land use, road density, canopy cover, human tolerance and Feeding Plant Species Richness and Density (FPSRD). Each grid was assigned with resistance values for above criteria ranging from 1 to 6. Overall resistance layer for S. v. nestor movement was created using ‘weighted overlay’ in GIS environment. The best potential habitat corridor was identified via least-cost modelling. The resultant corridor falls within an area which mainly comprises of forest and rubber (Hevea brasiliensis) monoculture. It further accounts for the highest human tolerance, canopy continuity, FPSRD and least road density. Resultant corridor can be improved by bridging existing gaps and enriching the corridor habitats which would play an important role in conservation of S. v. nestor by minimizing the isolation of local populations, ensuring the gene flow and maintaining the minimum viable metapopulation in the long run. This study further demonstrates that GIS can be used as an effective tool for least-cost modelling which helps to identify potential wildlife movement corridors at minimum cost.

Perceptions and Attitudes among Venders towards Non-human Primates in Mihintale Wildlife Sanctuary in Sri Lanka

A number of studies have revealed that age, gender, ethnicity, level of education, political attitude, landholding size, period of residency and religion all influence attitudes towards wildlife. Attitudes also exhibit regional differences. However, religious beliefs of Sri Lankans and cultural practices play an important role when deciding the perceptions and attitudes toward primates. An important feature of this country is the presence of monkeys at Buddhist temples and archeological sites. Social and environmental conditions are deeply and inextricably linked, an important component of conservation, and the management of human-wildlife conflict, is therefore the examination of people’s behaviour and perceptions regarding wildlife and the factors that influence these perceptions. This study was carried out in Mihintale wildlife Sanctuary in Anuradhapura district. To understand the nature of human attitude towards primates at the Mihintale wildlife sanctuary, the mixed methods approach was used for data collection. Interviews were conducted from April 2016 to September 2016. Direct interviews were conducted opportunistically with 57 venders in Sinhalese language to learn about macaques and langurs and their interactions with humans. The relationship with the venders and primates is complicated and filled with ambiguity. Venders are happy to see primates and other mammals in the wild, however, primates are not welcome near their business places. High population numbers and the inability to control monkeys are major concerns for venders. The nature of attitude onward each primate species depended on the level of interaction between humans and primate species. The attitude was negative toward the gray langurs and toque macaques, due to stealing of displayed toys, food items and the damage cause to the roofs of small shops, threatening venders and pilgrims when taking food by force. However, no negative attitude towards purple-faced leaf langurs. This study is important for conservation and for understanding the human perspective and attitude towards primates, when entwined with scientific evidence, offers a holistic understanding to one of the major problems in Sri Lanka, the human primate conflict. KEYWORDS: R eligious beliefs, Human-wildlife conflict, Primates, Perspective, Conservation

A GIS-Based Effort to Identify a Potential Movement Corridor for Western Purple-Faced Langur (Semnophithecus vetulusnestor), between Labugama-Kalatuwawa and Indikada Forest Reserves in Colombo District of Sri Lanka

The contribution of Labugama-Kalatuwawa Forest Reserve (LKFR) and Indikada Forest Reserve (IFR) in Colombo District of Sri Lanka, for maintaining viable populations of Western purple-faced langur (Semnophithecus vetulus nestor), have long been recognised. In between these two forests, a mosaic of unprotected land uses i.e., home gardens, rubber (Hevea brasiliensis) and rambutan (Nephelium lappaceum) monoculture, Seetawaka wet zone Botanical Garden and forest patches are scattered, isolating the two protected areas from each other. As the safe traversing of langurs between these two forests is not ensured at present, this study aimed to identify a potential linkage through developing a movement corridor for S. v. nestor between LKFR and IFR. The study was conducted in a 5.36 km2 strip of an unprotected landscape, located between LKFR and IFR which includes another small forest which is called Gatemawara Forest Reserve (GFR). The area was divided into 4ha grids and data were collected to prepare the five input layers: land-use type, road density, % canopy cover, human tolerance and feeding plant species richness and density (FPSD). It was assumed that the occurrence and abundance of S. v. nestor at a particular location, directly depends on the aforementioned factors. Using weighted overlay functions of ArcGIS 10.2.2, the layers were overlaid and an analysis of least-cost path was carried out to identify the best potential corridor. The resultant corridor passes mainly through forest and rubber land-uses, especially including GFR. In addition, the corridor grids account for the highest tolerance of langurs, canopy continuity and FPSD and least road density, all supporting to a successful transit. However, the corridor passes through Puwakpitiya-Thummodara main road, bisecting the landscape between LKFR and IFR which acts as a permanent barrier for langur movement. Still, this can be off-set by establishing proper crossing structures such as rope bridges. The current assessment indicates that there is considerable habitat connectivity for S. v. nestor, between LKFR and IFR. Further habitat enrichment across the corridor is recommended, which might allow S. v. nestor to be selective of those grids. In conclusion, when the existing gaps are bridged and the corridor habitats are enriched, the identified corridor would play an important role in conservation of S. v. nestor, minimizing the isolation of local populations, ensuring the gene flow and maintaining the minimum viable meta-population in the long run.Keywords: Wildlife corridors, Western purple-faced langur, Least-cost path analysis, Labugama-Kalatuwawa forest reserve, Indikada forest reserve

Diet Versus Phylogeny: a Comparison of Gut Microbiota in Captive Colobine Monkey Species

Both diet and host phylogeny shape the gut microbial community, and separating out the effects of these variables can be challenging. In this study, high-throughput sequencing was used to evaluate the impact of diet and phylogeny on the gut microbiota of nine colobine monkey species (N=64 individuals). Colobines are leaf-eating monkeys that fare poorly in captivity-often exhibiting gastrointestinal (GI) problems. This study included eight Asian colobines (Rhinopithecus brelichi, Rhinopithecus roxellana, Rhinopithecus bieti, Pygathrix nemaeus, Nasalis larvatus, Trachypithecus francoisi, Trachypithecus auratus, and Trachypithecus vetulus) and one African colobine (Colobus guereza). Monkeys were housed at five different captive institutes: Panxi Wildlife Rescue Center (Guizhou, China), Beijing Zoo, Beijing Zoo Breeding Center, Singapore Zoo, and Singapore Zoo Primate Conservation Breeding Center. Captive diets varied widely between institutions, but within an institution, all colobine monkey species were fed nearly identical or identical diets. In addition, four monkey species were present at multiple captive institutes. This allowed us to parse the effects of diet and phylogeny in these captive colobines. Gut microbial communities clustered weakly by host species and strongly by diet, and overall, colobine phylogenetic relationships were not reflected in gut microbiota analyses. Core microbiota analyses also identified several key taxa-including microbes within the Ruminococcaceae and Lachnospiraceae families-that were shared by over 90% of the monkeys in this study. Microbial species within these families include many butyrate producers that are important for GI health. These results highlight the importance of diet in captive colobines.

Stable carbon, oxygen, and nitrogen, isotope analysis of plants from a South Asian tropical forest: Implications for primatology.

Stable isotope analysis of primate tissues in tropical forest contexts is an increasingly popular means of obtaining information about niche distinctions among sympatric species, including preferences in feeding height, forest canopy density, plant parts, and trophism. However, issues of equifinality mean that feeding height, canopy density, as well as the plant parts and plant species consumed, may produce similar or confounding effects. With a few exceptions, researchers have so far relied largely on general principles and/or limited plant data from the study area as references for deducing the predominant drivers of primate isotope variation. Here, we explore variation in the stable carbon (δ13 C), nitrogen (δ15 N), and oxygen (δ18 O) isotope ratios of 288 plant samples identified as important to the three primate species from the Polonnaruwa Nature Sanctuary, Sri Lanka, relative to plant part, season, and canopy height. Our results show that plant part and height have the greatest effect on the δ13 C and δ18 O measurements of plants of immediate relevance to the primates, Macaca sinica, Semnopithecus priam thersites, and Trachypithecus vetulus, living in this monsoonal tropical forest. We find no influence of plant part, height or season on the δ15 N of measured plants. While the plant part effect is particularly pronounced in δ13 C between fruits and leaves, differential feeding height, and plant taxonomy influence plant δ13 C and δ18 O differences in addition to plant organ. Given that species composition in different regions and forest types will differ, the results urge caution in extrapolating general isotopic trends without substantial local baselines studies.

First Report on the White Morph Western Purple-Faced Leaf Langur (Trachypithecus vetulus nestor) in Sri Lanka

First Report on the White Morph Western Purple-Faced Leaf Langur (Trachypithecus vetulus nestor) in Sri Lanka

Additional Information Concerning ‘Erratum to: Western Purple-Faced Langurs (Semnopithecus vetulus nestor) Feed on Ripe and Ripening Fruit in Human-Modified Environments in Sri Lanka’

Additional Information Concerning ‘Erratum to: Western Purple-Faced Langurs (Semnopithecus vetulus nestor) Feed on Ripe and Ripening Fruit in Human-Modified Environments in Sri Lanka’

Preliminary survey of the distribution of four potentially zoonotic parasite species among primates in Sri Lanka

The occurrence of four parasitic species of zoonotic potential, Entamoeba coli , Entamoeba histolytica / dispar , Trichuris sp. and hookworm was investigated in the toque macaque, grey langur and the purple-faced langur at 32 sites across Sri Lanka. The study was carried out during the rainy season months of February - March in both 2007 and in 2009 and in December of 2010. 93 faecal samples were collected from 49 monkey troops at representative locations in altitudinal /climatic zones across the country where toque macaques (58 samples), grey langurs (21 samples) and purple-faced langurs (14 samples) naturally occur. Overall, the most common parasitic species found in all three primates were Trichuris sp. (28 %) and E. coli (25 %). Notably, hookworms were present in 23 % of the grey langur samples and 33 % of the toque macaque samples but absent in the purple-faced langur samples collected. Statistically significant variability in the prevalence levels across altitudinal/climatic zones was noted for toque macaques. Overall, group prevalence values in toque macaques decreased with increasing altitude; the highest values were found in the intermediate to arid lowland zones, and were lowest in the upland wet zone. Only Trichuris sp. and hookworm were found (13 %, 7 %, respectively) in the highland/ wet zone. Molecular analysis will be necessary to genetically type the parasite species before drawing firm conclusions about the status of zoonotic transmission between humans and non-human primates in the country. However this study highlights the need to systematically survey the human parasite population in areas where primates are commonly found to harbour these parasite species. J.Natn.Sci.Foundation Sri Lanka 2013 41 (4):319-326 DOI: http://dx.doi.org/10.4038/jnsfsr.v41i4.6246

Food Habits and Habitat use Patterns of Sri Lanka's Western Purple-Faced Langur

Sri Lanka's western purple-faced langur (Semnopithecus vetulus nestor) is Critically Endangered, mainly because of habitat loss due to deforestation. Reforestation to expand the langur's natural habitat became feasible when the present government mandated the use of native plants to increase the country's forest cover. For reforestation to benefit langur populations, however, the re-created habitat needs to be similar to the natural forest that provides food and space for their survival. This monkey's diet and the manner in which it uses its natural habitat are, therefore, being investigated as the first step. The diet and habitat use patterns of two groups, Tikira and Appu, were studied for 13 and 14 months respectively (n = 1695 hours). Scan sampling (with ten-minute sample periods) was used to record all activities observed in the groups and the trees on which these activities were performed. The plant parts eaten were also noted. Our results showed that Tikira used more species than Appu to perform all of its daily activities. Additionally, while the Tikira group used Dipterocarpus zeylanicus most frequently during most months, the Appu group had six species occupying the top rank during different months. Of the ten most frequently used species, only five were common to both groups, and the frequency of use of these plants was sometimes quite variable as well. With respect to diet, Appu used at least 27 species while Tikira fed on more than 41. The top-ranking food plants of the two groups were different, and among the top ten only four were the same. The top fifteen food plants of both groups constituted over 85% of their feeding records. Nineteen species eaten by Appu and 29 eaten by Tikira were exploited for less than two months, and the two groups ate no more than five species for more than seven months of the study. Although the two groups relied on different plants for much of their nutrition, nearly 86% and 74% of feeding observations of Appu (n = 422) and Tikira (n = 685), respectively, were of them feeding on leaves. Blossoms, fruits and petioles made up the remainder of the groups' diets. While these items contributed variable amounts to the monthly diet of both groups, none was exploited more frequently than leaves. The above results are compared to information from other non-human primates, and discussed with respect to reforestation. Two points are emphasized. One is that the langur living in its natural habitat is a typical folivore, unlike those living around home gardens. The other is that while field research is essential to reforest degraded habitats it must be conducted in conjunction with conservation education and other initiatives that are designed to dissuade people from destroying restored and intact natural habitats.

An ethnoprimatological approach to assessing levels of tolerance between human and commensal non-human primates in Sri Lanka.

Human and non-human primates increasingly are forced to live commensally, and understanding the human-nonhuman interconnections are paramount in understanding tolerance and conflict. In our study area, the heavily deforested parts of southern Sri Lanka humans and primates live side by side and prevalent religious tenets encourage a peaceful co-existence. We quantify the attitudes of rural communities towards three resident primate species (red slender loris, purple-faced langur, toque macaque) and wildlife conservation through semi-structured interviews with 301 people. Presence of the three primates on people' s land or farms was not related to the distance to the nearest forest but for langurs the incidence of crop-raiding was negatively related to distance to the forest. Despite Buddhist' s beliefs about 10% of interviewees indicated having killed primates (in the past) but levels of killing was not related to awareness of protective status of the primates. Overall however positive attitudes towards primates prevailed, without noticeable influence of sex, education or employment type. There was overwhelming support for forest protection measures - not because of the primates but mainly for water preservation and for ensuring a steady timber supply. We found that despite high levels of deforestation, and an increase of encroachment of humans into primate habitats, attitudes has led only to a limited increased level of tension between humans and primates.

A New Color Morph of the Southern Purple-faced Langur (Semnopithecus vetulus vetulus) from the Rainforests of Southwestern Sri Lanka

The southern purple-faced langur (Semnopithecus vetulus vetulus) is endemic to Sri Lanka and is listed as Endangered on the IUCN Red List. Following several decades of widespread deforestation in the country, viable habitat has been severely reduced for these arboreal, folivorous primates. Living close to densely populated human settlements has lead to further conservation difficulties. They have adapted to exploiting cultivated fruits in home gardens resulting in human-primate conflict, besides confronting electrocution hazards when crossing roads using power lines. The opening of the Colombo-Matara Expressway has also posed a threat, with the possibility of troops from either side becoming genetically isolated. Twenty-six troops were studied from 2007 to 2011 in the southwestern districts of Galle and Matara; of these, 14 contained one or more individuals with an atypical pelage coloration, which we call here a white color morph Two white alpha males were documented, along with adults, juveniles, and young of both sexes, totaling 30 individuals. The troops around Deniyaya and Getabarawa villages contained members that showed a distinct pelage, and all of the members of these troops had dissimilar cranial features and body size compared to other S. v. vetulus. Molecular analysis is now required to discover the genetic basis for this variation and any possible competitive advantages associated with its spread, with the possibility that this may originate a new subspecies. The discovery of a new color morph may provide an additional opportunity to promote primate conservation; greater national support is urgently needed considering the perilous future facing S. vetulus. Further research prospects and conservation recommendations are discussed in this paper.

Dietary Diversity and Food Selection in Hanuman Langurs (Semnopithecus entellus) and Purple-Faced Langurs (Trachypithecus vetulus) in the Kaludiyapokuna Forest Reserve in the Dry Zone of Sri Lanka

Understanding how ecological differences between sympatric species lead to coexistence is a fundamental question in primatology. Evidence for intraspecific dietary variation in colobines suggests that findings from a single study site may not be generalizable to other sites. Previous comparative studies of Semnopithecus entellus and Trachypithecus vetulus showed that S. entellus used seasonal plant parts more frequently than did T. vetulus. We examined whether these different food selection strategies can be generalized to explain the species' coexistence at a novel study locality. We collected dietary data for two groups of Semnopithecus entellus and one group of Trachypithecus vetulus between July 2008 and June 2009. We examined the monthly percentage of time devoted to feeding on specific dietary items in relation to their availability, compared the dietary niche breadth of the two species, and quantified the distribution and abundance of resources to examine the potential for intragroup and interspecific competition. Seasonal plant parts accounted for >90 % of the diets of both species and there were no significant differences in monthly dietary breadth or in the monthly proportions of time allocated to feeding on fruits, immature leaves, or mature leaves between the two species. Both species fed on fruits and flowers according to their availability, and most plants preferred by both primate species were relatively rare and clumped in distribution. Such resource distributions are suggested to promote both intragroup and interspecific competition. The food selection strategies of these two primate species are more similar at our study site than at previous study sites, and suggest that these species employ different strategies to facilitate coexistence at different sites.