Rhinopithecus bieti, A. Milne-Edwards, 1897

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 550-755 : 727-728

126.

Yunnan Snub-nosed Monkey

Rhinopithecus bieti

French: Rhinopitheque du Yunnan / German: Schwarze Stumpfnase / Spanish: Rinopiteco de Yunnan

Other common names: Black Snub-nosed Monkey

Taxonomy. Rhinopithecus bieti Milne-Edwards, 1897 ,

China, Yunnan, left bank of upper Mekong, Kiape, a day’s journey south of Atuntze (28° 25’ N, 98° 55’ E).

This species is monotypic.

Distribution. SW China, in SE Xizang Autonomous Region (= Tibet) and NW Yunnan Province (fragmented populations in the Yun Ling Mts), W of the Yangtze River and E of the Mekong River.

Descriptive notes. Head-body ¢.83 cm (males) and 74-83 cm (females), tail 52-75 cm; weight 15-17 kg (males) and 9-2— 12 kg (females). Adult Yunnan Snub-nosed Monkeys are blackish-gray above with contrastingly white underparts, white extending high up on flanks, backs of thighs, and sides of neck to form a ring around face. Tail is black, with a cow-like tuft at the end, and hairs on backs of thighs are very long and wavy, especially in adult males. Brow is black, and there is a thin, high, forward-drooping crest on crown. Facial skin is bright pink or red on muzzle, with traces of pale yellowish or greenish around eyes; fur wedges separating these zones are not as striking as in the Golden Snub-nosed Monkey ( R. roxellana ). Female Yunnan Snub-nosed Monkeys have shorter fur than males, and pelage is much more contrastingly colored in adult males; white backs of thighs particularly stand out in the field.

Habitat. Temperate montane evergreen, broadleaf deciduous, and conifer forest, preferring fir-larch or cypress forests, also areas of bamboo. The Yunnan Snub-nosed Monkeylives at higher elevations (3000-4700 m) than any other non-human primate, where temperatures average below freezing for several months of the year and snow can accumulate to over a meter in depth. The region itself is snow-covered for at least half the year. Yunnan Snub-nosed Monkeys use lower elevations in winter than summer. It is sympatric with the Rhesus Macaque ( Macaca mulatta ).

Food and Feeding. The Yunnan Snub-nosed Monkey is mainly folivorous and eats leaves and lichens, along with fruits, bark, berries, grasses, nuts, moss, seeds, shoots, and acorns. Lichens are important food items, making up ¢.67% of the diet. In Jinsichang, bamboo leaves form a large part of the diet. They will eat bird nestlings and also clay (geophagy). Diet varies largely by season.

Breeding. Mating of the Yunnan Snub-nosed Monkey peaks in August-September, and most births occur in March—-May. A single young is born after a gestation of 189-198 days. In captivity, the birth interval is c.2 years. Groups have a relatively high ratio of adult females to infants, indicating a low birth rate or low infant survival. Infant mortality in theirfirst harsh winter is 55-60%. Newborns are completely white, except for a blue face and pink fingers and toes. Their fur turns to light yellow as juveniles and then to gray. In subadults (age 4-8 years), back, sides, and ends of limbs first turn to light brown and then eventually black. Sexual maturity occurs at 5-6 years for males and 4-5 years for females.

Activity patterns. The Yunnan Snub-nosed Monkey is diurnal, arboreal, and terrestrial. Most of the day is dedicated to feeding (39%). It rests for c¢.35% of the day, indulges in social activities for 16%, and travels for c.10%. Yunnan Snub-nosed Monkeys sleep in dark conifer forest far from valley bottoms and often use the same sleeping site on consecutive nights.

Movements, Home range and Social organization. The Yunnan Snub-nosed Monkey lives in multimale-multifemale bands, comprised of unimale-multifemale and allmale groups. One band had 15-18 all-male groups. Large all-male groups may have as many as 14-16 individuals. Band sizes are ¢.24-370 individuals, and they have home ranges of 1000-4000 ha, with overlap with neighboring groups of ¢.30%. Mean daily travel distance is ¢.1300 m, and it is shorter in winter than summer. Indicating a matrilineal society, females tend to groom each other more than they groom males. It is probable that males rather than females disperse from their natal groups. Males often stand (or sit) guard over groups of up to eight playing infants and juveniles, while females forage and feed elsewhere. In captive groups, adult males can be protective of infants and young juveniles by intervening when older juveniles threaten or bully younger ones. Fission into smaller groupsis rare and usually only lasts for a day. Groups will split off from the band occasionally to drink in ponds, especially in the dry season. Males in all-male groups sometimes show aggression to other all-male groups at valued sleeping trees and waterholes and sometimes in feeding trees.

Status and Conservation. CITES Appendix I. Classified as Endangered on The IUCN Red List. Illegal hunting and trapping of the Yunnan Snub-nosed Monkey is the major threat; they are often caught in snares set for other animals (e.g. chevrotains, Moschus). Habitat loss, mainly from logging, but also clearing for summer grazing and agricultural land,is also a concern. Pesticide spraying was the cause of extinction of one entire subpopulation of ¢.50 individuals. In 2006, the total world population was estimated at less than 2000 individuals, with less than 1000 mature individuals in 15 subpopulations. Three subpopulations have been extirpated since 1994, but it is possible that still others await discovery. Eleven subpopulations occur in protected areas and four groups occur in unprotected forest fragments. The Yunnan Snub-nosed Monkey occurs in Hongla Snow Mountain National Nature Reserve, Baima Snow Mountain National Nature Reserve, and Laojun Mountain National Nature Reserve in China. Additional survey work is needed to find other subpopulations in non-surveyed regions. There is a major focus in China on captive breeding of the Yunnan Snub-nosed Monkey, with breeding pairs at the Kunming Zoo and Kunming Institute of Zoology. Most of these individuals were captured in the wild, and so far the program has achieved little success in being sustainable. The Yunnan Snub-nosed Monkey haslikely declined by well over 20% in the last two generations (c.25 years). A preliminary population viability analysis found that the five smallest subpopulations are at risk of declines and extinction in the next 100 years from effects of inbreeding and poaching, while the five largest subpopulations are apparently more secure. Since 1999, when a ban stopped most commercial logging in the region, habitat loss has slowed, butit could still be a major threat in the future. Clearing offorest land for summer grazing pasture reduced suitable habitat by 31% between 1958 and 1997. Fires set for agriculture are a threat in some areas, particularly in the Tibetan Autonomous Region.

Bibliography. Bleisch & Richardson (2008), Cui Liangwei (2003), Cui Liangwei & Xiao Wen (2004), Ding Wei & Zhao Qikun (2004), Groves (2001), Grueter (2004), Grueter & Zinner (2004), Grueter, Li Dayong, Ren Baoping, Wei Fuwen & van Schaik (2009), Grueter, Li Jinhua et al. (2010), Kirkpatrick (1996), Kirkpatrick & Long Yongcheng (1994), Kirkpatrick et al. (1998), Li Dayong et al. (2010), Li, Z. et al. (1980), Liedigk et al. (2012), Liu Zehua & Zhao Qikun (2004), Long Yongcheng et al. (1994), Quan Ruichang et al. (2011), Su Bing & Shi Liming (1995), Wu Baogi (1993), Wu Baogi & Xian Rulun (1994), Xiang Zuofu & Grueter (2007), Xiang Zuofu et al. (2007), Xiao Wen, Ding Wei et al. (2003), Xiao Wen, Huo Sheng etal. (2005), Yang Dehua (1988), Yang Shijian (2003), Yang Shijian & Zhao Qikun (2001), Zhao Qikun et al. (1988), Zhong Tai et al. (1998).

Figures

122. Red-shanked Douc (Pygathrix nemaeus), 123. Gray-shanked Douc (Pygathrix cinerea), 124. Black-shanked Douc (Pygathrix nigripes), 125. Tonkin Snub-nosed Monkey (Rhinopithecus avunculus), 126. Yunnan Snub-nosed Monkey (Rhinopithecus bet), 127. Guizhou Snub-nosed Monkey (Rhinopithecus brelichi), 128. Golden Snub-nosed Monkey (Rhinopithecus roxellana), 129. Stryker’s Snub-nosed Monkey (Rhinopithecus strykeri), 130. Pig-tailed Langur (Simaas concolor), 131. Proboscis Monkey (Nasalis larvatus)

Distribution. SW China, in SE Xizang Autonomous Region (= Tibet) and NW Yunnan Province (fragmented populations in the Yun Ling Mts), W of the Yangtze River and E of the Mekong River.