Distribution and Population Densities of Diurnal Primates in the Karst Forests of Phong Nha – Ke Bang National Park,Quang Binh Province,Central Vietnam

We studied the status and distribution of the diurnal primates in the Phong Nha – Ke Bang National Park (PNKB NP) from April to August 2007. In the past, researchers reported 9 primate species and subspecies for the karst forests of PNKB NP, which constitutes the most important protected area for the endangered Hatinh langur (Trachypithecus hatinhensis) in Vietnam. All 9 primate taxa are threatened due to hunting pressure and habitat loss. We applied line transect sampling in 4 areas. During a total of 117 transect inspections along 12 different transect routes, we confirmed 5 primate taxa and the analysis of population densities resulted in 2143 (±467) Hatinh langurs, 1316 (±871) red-shanked douc langurs (Pygathrix nemaeus), 930 (±489) stump-tailed macaques (Macaca arctoides), 986 (±883) eastern Assamese macaques (M. a. assamensis), and 18 (±18) southern white-cheeked crested gibbons (Nomascus siki) in the whole PNKB NP, which covers an area of ca. 85,000 ha. We could not detect the 2 nocturnal lorises, Bengal slow lorises (Nycticebus bengalensis) and pygmy slow lorises (N. pygmaeus), as well as rhesus macaques (Macaca mulatta) and northern pig-tail macaques (M. leonina). The distribution of the primates predominantly depended on human impact. We could not recognize a correlation between habitat constitution and abundance of primates. The population density estimates showed a much higher density of the Hatinh langur than previously assumed. Thus the importance of the PNKB NP for the conservation of this endangered langur increased significantly.     

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

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

Comparison of locomotor behaviour between white-headed langurs Trachypithecus leucocephalus and Francois' langurs T.fran(c)oisi in Fusui, China

We studied the locomotor behaviour of white-headed langurs Trachypithecus leucocephalus and Fran(c)ois' langurs T.fran(c)oisi to test two hypotheses: (1) these monkeys have evolved locomotor ability to support their activities on limestone hills,and (2) Fran(c)ois' langurs have evolved more diverse locomotor skills than white-headed langurs. Data were collected from 1996 - 1998 and in 2005 in Fusui Nature Reserve,Guangxi,and showed that the two species had similar locomotor types,but Francois' langurs had more locomotor modes (26) than white-headed langurs (12). Quadrupedal walking and leaping were two major types,and white-headed langurs were more arboreal than Fran(c)ois' langurs. We suggest that,while keeping their ancestral locomotor types,the two species have evolved new types allowing them to live on limestone cliffs. Compared to white-headed langurs,Francois' langurs have more diverse locomotor modes that probably have allowed them to live in more habitat types. As an evolutionary outcome,Fran(c)ois' langurs have a larger distribution range.     

Positional Behavior of Delacour’s Langurs (Trachypithecus delacouri) in Northern Vietnam

Information on positional behavior can help elucidate relationships between a species’ morphology, behavior, and environment. Delacour’s langurs (Trachypithecus delacouri) are similar to other colobines in body mass and intermembral index, yet inhabit a limestone karst environment. From August 2007 to July 2008, we collected 372 h of positional behavior and substrate use data from 8 groups of Trachypithecus delacouri in Van Long Nature Reserve, Vietnam to address questions about how the distinct —and potentially dangerous— features of karst influence colobine positional behavior. Results show that Trachypithecus delacouri is predominantly quadrupedal (66%). However, they exhibit differences that set them apart from many other colobines. Nearly 80% of locomotor and postural behaviors were performed on rocks. Leaping was remarkably infrequent, representing only 6% of overall locomotion. They leapt 3 times more frequently on trees (13%) than on rocks (4%) and more frequently used trees as a landing substrate than rocks (38% vs. 23%), both significant differences. We argue that rock (and cliff) travel is altogether different from terrestrial and arboreal travel and propose using the term petrous to indicate the substrate and incorporate the implications of its precise sharpness and verticality that lead to the complexities and risk of locomotion on rock surfaces. Trachypithecus delacouri does not show specific adaptations for limestone karst. Instead they appear to be a behaviorally flexible species and, owing to the generalized locomotor capabilities that characterize cercopithecids, capable of locomoting through and living in the limestone rock environment to which they have relatively recently been restricted.     

干扰生境下黑叶猴(Trachypithecus francoisi francoisi)日活动时间的分配

1999年至2000年,采用瞬间采样法对贵州省麻阳河国家级自然保护区干扰生境中的野生成年黑叶猴的日活动规律进行了研究。结果表明：干扰生境中野生成年黑叶猴在全年的行为时间分配中表现为休息和摄食所占比例最多,分别为35．41％和31．67％;其次是游走、拥坐和嬉戏,分别为14．44％、9．61％和8．54％;仅将很少时间用于理毛行为,为0．33％。与未干扰生境相比,干扰生境下黑叶猴全年中除用于休息的时间下降外,用于其余活动类型的时间均有所提高。研究还表明野生成年黑叶猴的活动规律在不同季节存在一定差异性。休息和摄食行为在各季节日活动规律中都存在显著高峰期,但高峰期持续时间和强度不同。游走、嬉戏和拥坐行为在各季节的日活动规律所占比例均较低。理毛行为存在季节有或无的现象。     

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...     

笼养黑叶猴拟母亲行为的观察

2002 年3～12 月, 采用焦点动物观察法和全事件行为记录法对南宁动物园人工饲养的5 群黑叶猴的拟母亲行为进行了观察。5 群黑叶猴中, 有幼体9 只, 成年个体19 只。观察发现非母雌性黑叶猴的拟母亲行为有怀抱、携带、接近、理毛、吻婴5 种类型; 各种行为类型发生的频次从高到低分别为接近(46.19 %) 、怀抱和携带(24.14 %) 、吻婴(20.36 %) 和理毛(9.31 %) 。通过比较还发现: 1) 幼体出生几个月内(4～8 月龄) , 黑叶猴拟母亲行为经常发生。2) 拟母亲行为的强度与幼体的年龄具有较大的关联性, 与非母雌性的育婴经验有关, 育婴经验缺乏的非母雌性对幼体表现出比有育婴经验的个体更强烈的兴趣。3) 拟母亲行为发生受幼猴母亲的默认程度的影响, 有些母亲不允许其它雌猴接触幼体。4) 拟母亲行为有助于缓解群内雌性个体间的冲突, 调节群内个体间的关系。     

Food availability,temperature, and day length drive seasonal variations in the positional behavior of white‐headed langurs in the limestone forests of Southwest Guangxi,China

Information on positional behavior contributes to the understanding of the ecological adaptation mechanisms in animals. We collected data on the positional behavior of white‐headed langurs (Trachypithecus leucocephalus) at the Guangxi Chongzuo White‐Headed Langur National Nature Reserve from September 2016 to August 2017 via instantaneous scan sampling method. This study aimed to examine the importance of positional behavior flexibility in limestone forests characterized by seasonal variations in climate and food resources. Our results indicated that langurs adopted leaping (47.92% ± 5.50%) and vertical climbing (40.13% ± 6.20%) as their predominant locomotor modes and sitting (83.08% ± 4.70%) as their predominant posture. Their positional behavior exhibited marked seasonal variations. More specifically, langurs used quadrupedal walking more frequently during the dry season than during the rainy months. In the stationary state, they sat more frequently during the dry season, whereas they laid and suspended more often during the rainy season. Their positional behavior was affected by fruit availability, day length, and temperature. Quadrupedal walking increased with the decrease in fruit availability, whereas leaping was positively correlated with fruit availability. Moreover, sitting was positively correlated with average temperature but negatively correlated with day length. Lying was also negatively correlated with temperature but positively correlated with day length. We conclude that white‐headed langurs adapt to limestone forests with positional behavior flexibility in response to seasonality. Our research provides evidence of the effects of food availability, ambient temperature, and day length on the positional behavior of white‐headed langurs, highlighting the need to understand their behavioral ecology and the influence of ecological factors on behavioral adaptation.     

Population census of the white-headed langur (Trachypithecus leucocephalus) at Longrui Karst Hills, Guangxi, China

A population census of white-headed langurs (Trachypithecus leucocephalus) was conducted using sleeping-site counts and the line-transect method from July to August 2002 at the Longrui Karst Hills, Guangxi, China. This area had been the largest habitat of the langurs across their range before the 1990s. While our survey revealed 146 old sleeping-sites, no white-headed langurs or fresh sleeping-sites were found in this area. Our study indicated that there had previously been a large population of langurs at Longrui Karst Hills, but now the langurs are possibly locally extinct in this area. If langurs still exist within the area, the population density must be very low. Interviews with local people confirmed that the number of white-headed langurs has been decreasing since the 1980s. Poaching was very common in the past and continues to be a problem at present, and it is likely that this has caused the decrease in the white-headed langur population at Longrui Karst Hills.     

A video-aided study of the diet of wild white-headed Langurs (Trachypithecus leucocephalus)

Asian leaf-eating monkeys have flexible, environmentally adaptable feeding strategies. The diet and food choices of white-headed langurs (Trachypithecus leucocephalus) have, however, not yet been studied in the Nongguan Karst Hills in China, where one of the two main surviving populations of this endangered species lives. From 2000 to 2002 inclusive, we adopted an innovative video playback analysis method to identify the food species used by the langurs and to calculate the corresponding feeding frequency for each species. The video-aided methodology was shown to be efficient. It provided high-quality images, and the plant species could be identified in 98.3% of the feeding records. Based on this analysis, we found that the langurs in Nongguan fed on 70 species of plants, among which 24 were identified as their staple food species. The cumulative curve for the staple food species reached a plateau at 255 (43.7%) feeding records. This result indicated that most of the langurs' staple food species had been identified by the analysis.     

Standardized descriptions of primate locomotor and postural modes

As quantitative studies on primate positional behavior accumulate the lack of a standard positional mode terminology is becoming an increasingly serious deficiency. Inconsistent use of traditional terms and inappropriate conflation of mode categories hamper interspecific and interobserver comparisons. Some workers use common terms without definition, allowing at least the possibility of misunderstanding. Other researchers coin neologisms tailored to their study species and not clearly enough defined to allow application to other species. Such neologisms may overlap, may completely encompass, or may conflate previously defined labels. The result is, at best, the proliferation of synonyms and, at worst, the creation of confusion where clarity had existed. Historical precedents have sometimes resulted in “catch-all” terms that conflate any number of kinematically different behaviors (e.g. “brachiation,” “climbing,” and “quadrumanous climbing”). We recognize three areas where distinction of positional modes has some current importance: (1) Modes that require humeral abduction should be distinguished from adducted behaviors; (2) locomotor modes that involve ascent or descent should be distinguished from horizontal locomotor modes; and (3) suspensory modes should be distinguished from supported modes. We recommend a nomenclature that is not dedicated to or derived from any one taxonomic subset of the primates. Here we define 32 primate positional modes, divided more finely into 52 postural sub-modes and 74 locomotor sub-modes.     

Seasonal Variation in the Activity and Dietary Budgets of Cat Ba Langurs (<Emphasis Type="Italic">Trachypithecus poliocephalus</Emphasis>)

Primate activity budgets are dictated by food availability and distribution; thus primates living in seasonal environments must adapt their behaviors to accommodate fluctuations in resources. Cat Ba langurs (Trachypithecus poliocephalus), a Critically Endangered Asian colobine and a member of the limestone langur group (francoisi superspecies group within genus Trachypithecus), live only in fragmented and disturbed habitats on Cat Ba Island, northeastern Vietnam. This study aimed to assess the behaviors and diet of Cat Ba langurs by group, age, sex, and season. We predicted they would have high rates of inactivity and foraging, low rates of social behaviors, with seasonal variation that reflects an energy-maximizing strategy. We conducted behavioral observations through scan sampling over an 11-month period and found that Cat Ba langurs spent a significant portion of their day inactive (57 %) followed by foraging (18 %), socializing (13 %), locomoting (10 %), and engaging in “other” behaviors (2 %). Their diet was made up primarily of leaves (83 %) followed by flowers (8 %), fruit (6 %), and stems (3 %). We found groups to differ in diet and activity, which is likely owing to differences in demographics and home range between groups. Seasonally, the animals ate more leaves and spent more time foraging in the dry season than the wet season, suggesting that they are energy maximizers. Cat Ba langurs have activity and dietary budgets similar to those of other limestone langurs, and respond to a presumed seasonal fluctuation in food availability similarly.     

笼养雌性黑叶猴尿中性腺激素水平变化与性行为、等级序位的关系

2003年10月30日至2004年11月21日,采集了3只笼养雌性黑叶猴妊娠期和1 只笼养雌性黑叶猴发情期的晨尿,并用放射免疫分析法检测尿液中孕酮和雌二醇浓度,同时用全事件观察法观察黑叶猴的行为,分析雌性黑叶猴的行为与其尿中的性腺激素的关系。研究结果发现:1)进入妊娠期,雌性黑叶猴尿中的雌二醇浓度逐渐上升,中后期达高峰;而尿中孕酮浓度在妊娠初期仍维持在放免法的灵敏度以下,妊娠约1 个月后才升高至灵敏度以上(13.39 ng/ mgCr);2)在妊娠中期,雌性黑叶猴仍维持着较高频率的邀配行为,但与雌激素的变化无明显的相关关;3)发情期,雌猴尿中的雌二醇浓度与其邀配行为呈正相关;4)雌性黑叶猴的性激素高低与其等级序位无关,但序位高的雌猴繁殖较早。     

Time budget of daily activity of Francois' langur (Trachypithecus francoisi francoisi) in disturbance habitat

The daily activity pattern of wild Francois' langurs (Trachypithecus francoisi francisi) was observed in disturbed habitat at Mayanghe National Nature Reserve of Guizhou Province, China, between 1999 and 2000. The behaviors of wild adult Francois' langurs were recorded at a 5-min interval using an instantaneous sampling method. The results indicate that resting, foraging, traveling, huddling, playing and grooming activities account for 35.41%, 31.67%, 14.44%, 9.61%, 8.54% and 0.33%, respectively, in the daily time budget of these adult Francois' langurs during the study period. In comparison with the results in undisturbed habitat, the decreased food availability in disturbed habitat changes the foraging behavior of langurs, and also changes time budgets of other behaviors, such as the increase of the proportion of traveling and the decrease of the proportion of resting. At the same time, the higher frequency of human activity in the disturbed habitat influences the time budget of daily social behavior of the langurs including playing, huddling and grooming. The patterns of activity rhythms of wild adult Francois' langurs in the disturbed habitat show some seasonal differences which are also discussed.     

Factors Affecting the Ranging Behavior of White-headed Langurs (<Emphasis Type="Italic">Trachypithecus leucocephalus</Emphasis>)

Ranging behavior is an important aspect of animal behavior that researchers use to investigate ecological influences on individual behavior. We studied the influence of diet, water resources, and sleeping sites on the ranging behavior of 2 groups of white-headed langurs (Trachypithecus leucocephalus) in a limestone habitat at Fusui Nature Reserve, China, between August 2007 and July 2008. During the study period, the total home range sizes for the 2 focal groups were 23.8 ha and 33.8 ha, the mean daily path lengths were 491 m and 512 m, and leaves accounted for 83.4% and 91.0% of the diet, which are well within the range of variation reported for other Trachypithecus. One focal group traveled significantly longer distances in the rainy season months than in the dry season months. This variation may be related to the seasonal difference in food availability and diet. The langurs did not use their home ranges uniformly, and 50% of their activities occurred within 11% (group 1) and 20% (group 2) of their home ranges. The most heavily used quadrats in the home ranges were located near the most frequently used sleeping sites. Moreover, the core areas (>70% of location records) of both groups’ home ranges included ≥1 permanent water pool. The langurs ventured to these pools for drinking when surface water became scarce in the dry season. These results suggest that sleeping sites and water scarcity may be significant influences on the ranging behavior of white-headed langurs in limestone habitat.     

Diet of the Delacour's langur (Trachypithecus delacouri) in Van Long Nature Reserve,Vietnam

The six limestone langur taxa of Southeast Asia inhabit the rugged limestone karst mountains, although the reason for their current restriction to this habitat is unclear. From August 2007 to July 2008, I collected data on the diet and feeding behavior of the critically endangered Delacour's langur (Trachypithecus delacouri) in Van Long Nature Reserve, Vietnam. I used these data to evaluate the hypothesis that limestone langurs are found on karst habitat because they depend on endemic limestone plants. Feeding accounted for 29% of the langurs' activity budget. Young leaves dominated the diet monthly, seasonally, and annually. The annual diet consists of nearly 79% foliage with almost 60% young leaves. Despite a distinct wet and dry season, over the study period, seasonal variation in plant part consumption was slight. Fruit and seeds were a small contribution to the diet. Delacour's langurs ate 42 of 145 available species, and they concentrated on a subset of this number. Five plant species comprised more than 60% of the diet and 16 species comprised more than 93%. More than half of the diet came from climbers. Delacour's langurs are among the most highly folivorous of studied colobines and, along with the closely related T. leucocephalus of southern China, the most folivorous of the Asian langurs. Whether high folivory is owing to a lack of available fruits and seeds in limestone habitats is unknown. What is certain, however, is that the plant species most important in the Delacour's langurs' diet at VLNR, throughout the study, were not plants endemic to limestone. Feeding dependence alone, therefore, cannot explain the current distribution of limestone langurs on karst habitat. Am. J. Primatol. 72:317–324, 2010. © 2009 Wiley‐Liss, Inc.     

Status of Trachypithecus geei in a Rubber Plantation in Western Assam, India

Golden langurs (Trachypithecus geei) are an endangered species in a limited area of Northeast India and Bhutan. They are confined to a forest belt in western Assam between the Manas River in the east, Sankosh in the west and Brahmaputra in the south along the Indo-Bhutan border. Due to habitat destruction, their populations are restricted to fragmented forest pockets, especially in India. We compared data on an isolated population of golden langurs in the rubber plantation of Nayakgaon in the Kokrajhar district of Assam, May 2002 with an earlier census in 1997. We counted a total of 52 individuals in 3 troops in 2002. The average troop size is 17.3 (r = 7–26). The ratio of adult male to adult females is 1:3.16. Of the total population 9.6% were adult males, 21.1% were adult females, 17.3% subadult males, 7.7% subadult females, 19.2% juveniles and 25% infants. In 1997 Srivastava et. al., recorded 38 individuals in 5 troops with an average troop size of only 7.6 . Apparently troop fusion has occurred. The increased population is encouraging.     

Variations in diet composition of sympatric Trachypithecus francoisi and Macaca assamensis in the limestone habitats of Nonggang,China

Comparative studies of sympatric species are essential for understanding behavioral and ecological adaptation as well as the mechanisms that can reduce resource competition to allow coexistence.Fran?ois' langurs(Trachypithecus francoisi) and Assamese macaques(Macaca assamensis) are sympatric primate species found in the limestone seasonal rainforests of Nonggang Nature Reserve,southwestern Guangxi, China. To explore their different adaptation strategies, we collected data on diet using scan sampling at 15-min intervals. Our results revealed that Fran?ois' langurs showed a more flexible diet composition than Assamese macaques.Fran?ois' langurs increased dietary diversity and mature leaf consumption in response to seasonal scarcity of preferred young leaves and fruits, whereas Assamese macaques relied heavily on young bamboo leaves(Indocalamus calcicolus) in most months.These variations reflect the differences in digestive physiology, morphology, and the temporal and spatial distribution of food resources.     

云南无量山印支灰叶猴社会结构初步研究

乌叶猴属物种主要以一雄多雌的小群活动,其群体大小一般不超过20只。泰国东北部的印支灰叶猴生活在一雄多雌或多雄多雌群的小群中,而云南无量山的印支灰叶猴却生活在多雄多雌的大群中,有些群大小超过100只,但是对无量山印支灰叶猴的社会结构缺乏研究。2012年9月至2015年7月,在云南无量山国家级自然保护区大寨子片区开展一群习惯化印支灰叶猴的社会结构研究。采用10min间隔的焦点动物瞬时记录法,记录焦点成年雄性5 m范围内不同性别年龄个体的数量。观察期间共有594次准确识别焦点雄性5 m范围内其它个体年龄性别的有效数据 (至少有1只其他个体)。其中,焦点雄性周围出现其它成年雄性的几率为44.2%,数量为(0.62 ± 0.85)只;同时出现成年雄性和成年雌性的几率是32.5%。取食时焦点雄性周围出现其它雄性的比例 (60.0%) 和数量 (平均0.93只) 都大于休息和移动时,数量最多为5只成年雄性。结果表明该群灰叶猴的社会结构不是由多个OMU和AMU组成的重层社会,而是多雄多雌的社会结构。无量山印支灰叶猴群内成年雄性间相互容忍度较高,个体的空间分布在取食时尤其密集,说明无量山印支灰叶猴的食物丰富 (至少在某些季节),这也部分解释了为什么无量山印支灰叶猴能够生活在大群中。本文为进一步研究亚洲疣猴社会结构的多样性和进化提供了重要的基础资料。