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Rapid global deforestation has forced many of the world's primates to live in fragmented habitats, making the understanding of their behavioral responses to degraded and fragmented habitats a key challenge for their future protection and management. The black-and-white snub-nosed monkey (Rhinopithecus bieti) is an endangered species endemic to southwest China. The forest habitat ranges from near-continuous to fragmented. In this study, we investigated the activity budget and diet of a R. bieti population that live in an isolated and degraded habitat patch at Mt. Lasha in Yunnan Province, near the current southern limit of the species. We used our data along with data from six other sites in more-continuous habitats across its range to model factors that predict stress, including feeding effort and time feeding on lichens against potential predictive parameters. Models showed feeding effort across all sites increased with increasing altitude and latitude, and with decreasing food species diversity. There was also a strong positive relationship between feeding effort and time feeding lichens. The Mt. Lasha R. bieti population exploited a total of 36 food species, spending 80.2% of feeding time feeding on lichens, Bryoria spp. and Usnea longissima. These figures are more comparable to those living in the north than those living in the mid- and southern part of the species' range. Given the models for feeding effort and time feeding on lichens, the unexpectedly high time spend feeding on lichens and feeding effort relative to latitude and elevation are suggestive of a stressed population at Mt. Lasha.

Seasonal variation in environmental factors is vital to the regulation of seasonal reproduction in primates. Consequently, long-term systematic data is necessary to clarify the birth seasonality and pattern of primates in highly seasonal environments. This study indicated that black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Mt. Lasha exhibited strict birth seasonality with a pulse model. Infants were born with a certain degree of synchronization. Birth distribution showed three birth peaks, and the birth pattern showed a "V" style in even-numbered years and a gradual increase in odd-numbered years. The beginning date, end date and median birth date were earlier in even-numbered years than those in odd-numbered years. The higher latitude of their habitats, earlier birth date, shorter birth period, fewer birth peaks and stronger birth synchrony might be adaptations for strongly seasonal variation in climate and food resources. After the summer solstice when daylight length began to gradually shorten, R. bieti at Mt. Lasha started to breed during the period with the highest environmental temperature and food availability, which implied that photoperiod may be the proximate factor triggering the onset of estrus and mating. It appears that R. bieti coincided conception and mid-lactation with the peak in staple foods, and weaning with the peak in high quality of foods. Thus, food availability was the ultimate factor regulating reproductive seasonality, and photoperiod was the proximate factor fine-turning the coordination between seasonal breeding and food availability.

Different types of dominance hierarchies reflect different social relationships in primates. In this study, we clarified the hierarchy and social relationships in a one-male unit of captive Rhinopithecus bieti observed between August 1998 and March 1999. Mean frequency of agonistic behaviour among adult females was 0.13 interactions per hour. Adult females exhibited a linear hierarchy with a reversal of 10.9%, indicating an unstable relationship; therefore, R. bieti appears to be a relaxed/tolerant species. The lack of a relationship between the agonistic ratio of the adult male towards adult females and their ranks indicated that males did not show increased aggression towards low-ranking females. Differentiated female affiliative relationships were loosely formed in terms of the male, and to some extent influenced by female estrus, implying that relationships between the male and females is influenced by estrus and not rank alone. A positive correlation between the agonistic ratio of adult females and their ranks showed that the degree to which one female negatively impacted others decreased with reduction in rank. Similarly, a positive correlation between the agonistic ratio of females and differences in rank suggests that a female had fewer negative effects on closely ranked individuals than distantly ranked ones. These data indicate that rank may influence relationships between females. A steeper slope of regression between the agonistic ratio and inter-female rank differences indicated that the extent of the power difference in high-ranking females exerting negative effects on low-ranking ones was larger during the mating season than the birth season, suggesting that rank may influence the mating success of females.

Food selection by folivorous primates is thought to relate to macronutrients, micronutrients and plant secondary metabolites. However, few studies explain their effects on food choices. This study was designed to clarify the effect of phytochemical components on Rhinopithecus bieti food choice by analyzing the chemical composition of food samples collected from March to May in 2010 and 2011 at Mt. Lasha in northwest Yunnan, China. Compared with non-foods, there was more phosphorous and crude protein, less total sugar and a lower ratio of calcium to phosphorus in selected foods. However, no differences were found in crude fat, crude ash, calcium and tannin content between foods and non-foods. Phytochemical constituents may influence food choices; the monkeys preferred foods with high phosphorus and low Ca/P, low calcium, low sugar and low tannins. Rhinopithecus bieti foraged high quality foods such as buds and young leaves to meet their nutritional needs after a long winter. Therefore, if tannin content in food did not exceed the enduring threshold of R. bieti, the nutrient intake was prioritized by phosphorus and calcium regulation when the need for macronutrients dominated by protein was satisfied.

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) inhabit one of the harshest habitats by any nonhuman primate. Reliable predictive cues to initiate reproduction may be particularly critical for R. bieti because they inhabit such seasonally energetically challenging environments. To better understand the seasonal distribution of and predictive cues to reproduction, we collected breeding and birth data in a population of R. bieti at Mt. Lasha in Yunling Nature Reserve, Yunnan, China, from January 2008 to May 2010, using a combination of 10-min instantaneous scans and ad libitum observations. We examined variations in temperature, rainfall, and food availability, as well as photoperiod differences between Mt. Lasha and the more northerly Xiaochangdu to identify environmental influences on the timing of reproductive events. Our data show the area exhibited distinct seasonal fluctuations in rainfall, temperature, and food availability. Mating occurred year-round, but peaked in August, coinciding with the end of the period of highest temperatures and food availability, and during the peak rainfall. Copulation frequency peaked 1 month after corresponding peaks in staple foods, rainfall, and minimum temperatures, and 3-4 months after peaks in high-quality foods. Births were significantly seasonal, with a birth peak from mid-February to early April, and a mean birth date of 14 March. Eleven births occurred in 41 days in 2009, and 16 births occurred in 52 days in 2010. Births occurred during periods of increasing temperatures and food availability. Our findings are suggestive of at least one environmental control of conception timing, and support the notion that food availability during key reproductive stages is an ultimate factor for birth seasonality, but provide no supporting evidence for photoperiod during the conception season as a proximate cue to reproduction in R. bieti.

Copulation patterns are important to understanding male mating strategies and stabilization strategies of social organizations in primates. However, information on copulation patterns of Asian primates is relatively rare. This study was undertaken to collect data on mating behavior and birth seasonality of Black-and-white Snub-nosed monkeys (Rhinopithecus bieti) using all occurrence sampling and Focal animal-scan sampling methods at Mt. Lasha, between January and December, 2011. Our study focused on observing mating frequency and birth rates. Snub-nosed monkeys mate year round, with two observable peaks: one reproductive peak during the mating season, roughly from August to October, and a second non-breeding peak during the birth season. It is unclear what biological significance this non-reproductive mating peak has. During our observation, we noted a lower ratio of mount to ejaculation and rare ejaculatory copulations, which indicated that every mating would not result in ejaculation. This study corroborates the previous view that the Rhinopithecus bieti's copulatory pattern is likely multiple-mount ejaculation (MME) or at the upper part of mating continuum of single-mount ejaculation (SME) toward MME. More ejaculatory copulations initiated by males than females indicate that MME is not only a mating strategy of males, but that males can influence the position of their copulatory pattern on the continuum between SME and MME. The mating frequencies significantly correlated with the birth rates with a delay of 6 to 7 months. Monkeys gave birth within a strict seasonality with a birth peak of March, which confirms the previous view. Infants were born with a certain degree of synchronization, but different populations displayed different modes of synchronizations.

Found in the Trans-Himalayas of north-west Yunnan and south-east Tibet, the black-and-white snub-nosed monkey (Rhinopithecus bieti) is one of the world's most endangered primates. A recent survey indicates that only 15 groups with 2500 individuals remain in the wild. However, the Tibetan Xiaochangdu group may be the only equilibrium group in the field since the last investigation in 1988. To evaluate the effects of traditional culture and socioeconomic activity on biodiversity conservation of R. bieti, we conducted a case study in the Honglaxueshan National Nature Reserve in southeast Tibet from June 2003 to May 2005. Interviews, direct observations, and analysis of socioeconomic data indicated major advantages to the conservation of R. bieti, which included that: 1) traditional culture mainly depended on raising livestock and collecting non-timber products rather than forest planting of Tibetan highland barley; 2) religious beliefs, against to kill any wildlife living on the sacred mountain, were mainly influenced by Tibetan Buddhism; and 3) bigger household numbers were induced by the polyandrous marriage system, which resulted in lower per capita resource consumption than smaller ones.

Data on social organization of two bands of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were collected when the monkeys were crossing an open spot at Nanren and Bamei (northwest of Yunnan, China) using a sampling rule where individuals within one social unit are spatially closer to each other than individuals between social units. The typical pattern of social organization in this sample was multiple adult females (AFs) and their offspring with one adult male (AM) in a one-male unit (OMU), similar to that of many other colobines. In such units, on average one male is associated with 4.0 AFs and 2.5 of their offspring. Moreover, there are multimale/multifemale units and monogamous units besides OMUs. All bisexual units traveled together with at least one all-male unit as a cohesive band. In two bands of monkeys, 87% of AMs in bisexual units were within OMUs, 7.8% within monogamous units and 5.2% within multimale, multifemale units. In the Bamei band, 6.7% of AMs were in the all-male unit. The size of OMUs in the Nanren band was larger than that of the Bamei band, with more AFs and juveniles, which may be related to better conservation in the Nanren band's habitat. For the Nanren band, the average number of AFs in OMUs varied across time, increasing from 4.3 in 1994 to 5.1 in 2001, and then decreasing to 3.8 in 2005. This article suggests three possible explanations for this variation, but more data are needed for these hypotheses to be tested., ((c) 2007 Wiley-Liss, Inc.)

This study, which is based on 10 years of birth records, shows that black-and-white snub-nosed monkeys (Rhinopithecus bieti) in captivity display marked birth seasonality. The birth season starts in December and ends in June, with a peak from March to May, and a median birth date of April 10. More male infants than female ones are born in captivity. More males were born at the Kunming Institute of Zoology (KIZ) than at the Kunming Zoo (KZ). Of 17 interbirth intervals (IBIs), 29% were from females that had lost an infant at <1 year of age or experienced stillbirth, and 71% were from females whose infant survived more than 1 year. The mean IBI for the former group (428+/-SD 87 days) was significantly shorter than that for the latter group (706+/-71 days), in agreement with reports of other Colobine species. Infant mortality was lower in captivity than in the field, which may reflect the relatively stable food availability and climate in captivity compared to the harsh conditions in the wild., (2005 Wiley-Liss, Inc.)