Animal Info - Yunnan Snub-nosed Monkey

(Other Names: Biet's or Black Snub-nosed Monkey, Black or Yunnan Golden Monkey, Yunnan Snub-nosed Langur)

Rhinopithecus bieti (Pygathrix bieti, P. roxellana bieti, )

Status: Endangered


Contents

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Weight, Habitat, Age to Maturity, Gestation Period, Birth Season, Birth Rate, Diet, Behavior, Social Organization, Age and Gender Distribution, Density and Range)
5. References


Profile

Pictures: Yunnan Snub-nosed Monkey #1 (14 Kb JPEG) and Yunnan Snub-nosed Monkey #2 (16 Kb JPEG) (Sci. Museums China)

The Yunnan snub-nosed monkey averages 9 kg (20 lb) (females) to 15 kg (33 lb) (males). It lives in high-altitude evergreen forests between 3000 - 4500 m (9800 - 14,800'), where temperatures average below 0 deg C (32 deg F) for several months of the year and snow can accumulate to over 1 m (3.3') in depth. The primary food of the Yunnan snub-nosed monkey appears to be lichens growing on tree bark. Unlike other arboreal primates, the Yunnan snub-nosed monkey forms groups that can number more than 200.

In the 1890's, French scientists first reported the existence of the Yunnan snub-nosed monkey.  For decades after this, however, zoologists could not determine whether it still survived, and some suggested that it was extinct.  In 1962 its existence was confirmed. Currently, it is found in the Yunling Mountains in southwestern China.   Recent surveys suggest there are 13 isolated sub-populations located in five counties in Yunnan Province and Tibet Autonomous Region.

The Yunnan snub-nosed monkey has suffered from loss of habitat and intensive hunting and trapping. It is also caught in snares set for other animals, such as musk deer. Its population is fragmented, and geographic features make it improbable that there is exchange of individuals between the 13 sub-populations.


Tidbits

*** "According to local people ... in the 1960's ... no one hunted [the Yunnan snub-nosed monkey] because there was plenty of wildlife and, in addition, local people regarded them as being closely related to humans.  Later this tradition broke down and young people began to poach them." (Yang 1988)

*** "Five hunters were encountered during the October survey; all knew of regulations against hunting snub-nosed monkeys, but none appeared concerned about enforcement." (Zhong et al. 1998).

*** The Yunnan snub-nosed monkey lives at a higher altitude than any other non-human primate.


Status and Trends

IUCN Status:

Countries Where the Yunnan Snub-nosed Monkey Is Currently Found:

2004: Occurs in China (IUCN 2004).

Population Estimates:

[Note: Figures given are for wild populations only.]

History of Distribution:

In the 1890's, French scientists first reported the existence of the Yunnan snub-nosed monkey.  For decades after this, however, zoologists could not determine whether it still survived, and some suggested that it was extinct.  In 1962 its existence was confirmed. (Su & Shi 1995) In the late 1960's, it was reported to occur in northwest Yunnan close to the frontier with Burma, along  the high narrow ridge separating the Mekong and the Yangtze (Simon & Geroudet 1970)

Currently, it is found between longitude 98 deg 37' to 99 deg 41' E, and latitude 26 deg 14' to 29 deg 20' N in the Yunling Mountains in southwestern China.  Recent surveys suggest that there are 13 isolated sub-populations located in five counties in Yunnan Province and Tibet Autonomous Region (Ren et al. 1997) between the Jinsha River and Lantsang River (CAS 2003).

Threats and Reasons for Decline:

The Yunnan snub-nosed monkey has suffered from loss of habitat and intensive hunting and trapping. It is also caught in snares set for other animals, such as musk deer. Its population is fragmented, and geographic features make it improbable that there is exchange of individuals between the 13 sub-populations (Ren et al. 1997).


Data on Biology and Ecology

Weight:

Females: 9.1 kg (20 lb) (average; n = 7); males: 15.3 kg (33.7 lb) (average; n = 5) (Ren et al. 1997)

Habitat:

The Yunnan snub-nosed monkey lives in high-altitude evergreen forests, with the canopy composed mainly of fir, spruce, evergreen oak and rhododendron species between 3000 - 4500 m (9800 - 14,800').   Temperatures average below 0 deg C (32 deg F) for several months of the year and snow can accumulate to over 1 m (3.3') in depth. (Ren et al. 1997)

The Yunnan snub-nosed monkey is found in the Mountains of Southwest China Biodiversity Hotspot (Cons. Intl. 2005)

Age to Maturity:

In the genus Rhinopithecus, males reach sexual maturity at 7 years, females at 4 - 5 years (Nowak 1999).

Gestation Period:

Reported to be about 200 days for the genus Rhinopithecus (Nowak 1999).

Birth Season:

July and August.

Birth Rate:

In the genus Rhinopithecus, one young is usually born, occasionally two. (Nowak 1999)

Diet:

The primary food of the Yunnan snub-nosed monkey appears to be lichens growing on tree bark, supplemented by leaves (e.g. from plants in the rose family and the grass family) and, at certain times of the year, fruits, acorns and/or seeds.  Studies have indicated that lichens compose over 80% of the diet (Ren et al. 1997, Zhong et al. 1998).

Behavior:

The Yunnan snub-nosed monkey is most active in the early morning and afternoon and rests around midday. Adults have been reported to spend 20 - 90% of the time on the ground.

Social Organization:

Unlike other arboreal primates, the Yunnan snub-nosed monkey forms groups that can number more than 200 (Zhong et al. 1998). In fact, group size varies considerably, having been reported at numbers ranging from 23 - 269 (Davies & Oates 1994, Yang 1988).

Age and Gender Distribution:

In two groups studied, the ratio of adult males to adult females was 1.0:3.0 and 1.0:3.7, and the ratio of infants to females was 1.0:2.8 and 1.0:3.4 respectively (Zhong et al. 1998).

One study reported that the average family size was 7, including 1 adult male, 3 adult females, 1 juvenile, 1 yearling and 1 infant (Camb. Univ. Exp. Soc. 2000).

Density and Range:

Density:

  • 1.3 monkeys/sq km (3.4 monkeys/sq mi) (Bamei group); 5.0 monkeys/sq km (13 monkeys/sq mi) (Shalin group)
  • 1.1 - 2.5 monkeys/sq km (2.9 - 6.5 monkeys/sq mi) (6 Baima groups)
  • 7.0 monkeys/sq km (18 monkeys/sq mi) (Wuyapiya/Nanren group)

(Zhong et al. 1998)

Differences in population density estimates may result from differences in the time-scale for estimates of home range size.  Groups cover large areas, apparently because lichens, their primary food, require a decade or more to replenish themselves. Thus an observation period of less than a decade may only document a group in part of its range. (Zhong et al. 1998)

Home Range:

  • 46 sq km (18 sq mi) (Bamei group - 50 - 60 members)
  • 4 sq km (1.5 sq mi) (Shalin group - at least 20 members)

(Zhong et al. 1998)


References

Arkive, Camb. Univ. Exp. Soc. 2000, CAS 2003, Cons. Intl. 2005, Davies & Oates 1994, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Nowak 1999, Ren et al. 1997, Sci. Museums China, Simon & Geroudet 1970, Su & Shi 1995, Tan 1997, Yang 1988, Zhang 1998, Zhong et al. 1998


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Last modified: March 17, 2005;

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