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.     

仰鼻猴属(RHINOPITHECUS)的系统分类地位

自Milne-Edwards(1868-1974)将四川宝兴标本另立新属--仰鼻猴属(Rhinopithecus,1872=Semnopithecus,1870)以来,其属名一直被分类学家、形态学家和灵长类学家等所承认和采用(Elliot,1913; Hill,1936; Allen,1938;Simpson、1945;Buettner-Janusch,1963;Napier等,1967,等)。     

Distribution and Conservation Status of the Red-Shanked Douc (Pygathrix nemaeus) in Lao PDR: An Update

The endangered red‐shanked douc (Pygathrix nemaeus), endemic to Lao PDR, Vietnam, and perhaps Cambodia, remains little known. The Lao population is highly threatened. To improve conservation prospects of the species there, we here update a status review from 1999. Subsequent literature (mostly not readily available to the outside scientific community) was reviewed critically. Doucs and their habitat in Lao PDR faced continuous, increasing threats in the past 10 years through large development projects and heavy hunting. Many locations with records from the 1990s were not surveyed in the last decade, so douc persistence remains uncertain in them. Given the poor status of the species in Vietnam and Cambodia, the Lao population is surely the world's largest and the best hope for the species’ global conservation. Resources for conserving species are very limited in the country, urging prioritization of populations, so available resources have maximum effect. Nakai–Nam Theun and Hin Namno National Protected Areas hold the largest populations of P. nemaeus, but face great threats from hunting. Management of these areas (and secondary priority areas) should focus on control of this illegal activity. Am. J. Primatol. 74:874‐889, 2012. © 2012 Wiley Periodicals, Inc.     

Sleeping Site Use by <Emphasis Type="Italic">Trachypithecus francoisi</Emphasis> at Nonggang Nature Reserve,China

We collected data on sleeping site use of the François’ langur (Trachypithecus francoisi) between August 2003 and July 2004 at Nonggang Nature Reserve, China. We tested hypotheses regarding possible ultimate causes of sleeping site selection in light of our results. Langurs selected the ledges and caves on cliffs as sleeping sites. Of 23 identified sleeping sites, 7 were more frequently used than the others (≥9 times each, accounting for 64% of total observed nights). Langurs used most sleeping sites repeatedly, and reused some of them on consecutive nights; 4 consecutive nights were the longest run. We suggest that langurs choose sleeping sites to make approach and attack difficult by predators, and to increase familiarity so as to improve chances for escape. Langurs’ cryptic behaviors before entering sleeping sites and the rapid movement toward sleeping sites (4 min on average) with an increased level of vigilance may help to decrease the possibility of detection by predators. Access to food appears to have a profound influence on sleeping site selection in François’ langurs, as demonstrated by the langurs’ tendency to select sleeping sites close to their current main feeding sites. The position of sleeping site relative to the last feeding site of the day and the first feeding site of the subsequent morning indicated a strategy closer to that of a multiple central place forager than of a central place forager. Our results do not support the influences of other factors, e.g., avoidance of parasites, seeking comfort, and range or resource defense, on sleeping site selection.     

Adult male replacement and social change in two troops of hanuman langurs (Presbytis entellus) at Jodhpur,India

I studied the process of adult male replacement and social change in two one- male troops (B20 and B21) of hanuman langurs (Presbytis entellus)at Jodhpur, India. Male-male competition lasted for about 6 months before the successful takeover of one troop (B20). During that period, five adult males from three neighboring bands (AMB7, AMB9, and AMB10) and a resident male of a neighboring troop (B21) were involved in taking over the troop. The latter male also copulated with six females during his interim residency, which suggests that he may have opportunistically maximized his mating chances with females of a neighboring group. During an intertroop interaction, a 14-month-old female infant of the other troop (B21) was fatally attacked by an adult female of the first troop and the infant eventually died. The attacker may have taken advantage of the disorganization created by male-male competition, perhaps to eliminate a future food competitor. In addition, the first troop gained an additional feeding area from the other troop’s range; it included a sleeping site and a waterhole, indicating that territorial fights during social instability may have led to the expansion of the winner’s resource area.     

白河自然保护区川金丝猴及其保护管理建议

在野外调查的基础上对白河自然保护区的川金丝猴野外生态学进行阐述,对其种群发展的主要影响因素提出了评价。结合生态学和受迫因素提出了该保护区川金丝猴资源的保护管理建议。     

Epizootic fatal amebiasis in an outdoor group of Old World monkeys

Background Entamoeba (E.) histolytica is an obligate parasite of humans and non‐human primates. Methods This report describes the pathomorphological, immunohistological, and microbiological findings of fatal E. histolytica infection in two mantled guerezas (Colobus guereza) and one Hanuman langur (Semnopithecus entellus) from an epizootic outbreak of amebiasis in an open‐range recreation park. Results Pathomorphological examination revealed multifocal necrotizing and granulomatous hepatitis with intralesional protozoan trophozoites in all three cases. In addition, necrotizing and ulcerative gastritis was detected in both mantled guerezas. Furthermore, oligofocal acute pulmonary embolization was detected in one of these cases. No extra‐hepatic lesions were observed in the Hanuman langur. Immunohistological examination confirmed the etiologic diagnosis of E. histolytica‐induced lesions. Conclusions Although E. histolytica is a rarely diagnosed pathogen in Western European countries, veterinarians and animal keepers involved in handling and care taking of non‐human primates should be aware of the potential threat caused by this zoonotic parasite.     

Possible audience effect in Thomas langurs (Primates; Presbytis thomasi): an experimental study on male loud calls in response to a tiger model

Recent research indicates that animal vocalizations can refer to objects in the outside world, and that call production may be controlled by the sender depending on the type of audience involved. Our research on wild male Thomas langurs (Primates: Presbytis thomasi) shows that these males call as a response to a tiger model when they are in a group, but do not call when they are solitary. This is the first experimental study on wild primates to demonstrate that the presence or absence of an audience influences calling behavior. Our results indicate that males in mixed-sex groups give more loud calls than solitary males when exposed to a predator model. This suggests that giving loud calls in response to predators is not purely a reflex and may be controlled in some way by the sender.     

Status and distribution of golden langurs (Trachypithecus geei) in Assam, India

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.     

Attacks on adult females with infants by non-resident males in the François langur

Infanticide by males is a common phenomenon in mammals, especially primates, as lactation lasts much longer than gestation in many species. Usually, infanticidal episodes occur soon after group takeovers, and are traditionally considered a male reproductive strategy (i.e., support the sexual selection hypothesis, Hrdy, 1974). To verify the validity of this conception, we observed one group of François’ langurs in the Nonggang Nature Reserve, China, between August 2003 and July 2004. During the study period, a François’ langur female with the youngest infant in the group was attacked three times by immigrating males, and later disappeared by the third day after the final attack. We suggest that these attacks on the female-infant dyad represent infanticide attempts by males, and may be the cause of the adult female and her infant’s disappearance. Presumably, that female dispersed with her infant to avoid infanticide and was not killed. Though these observations do not completely verify the sexual selection hypothesis, they are not inconsistent with it.