Animal Info - Tonkin Snub-nosed Monkey

(Other Names: Dollman's Snub-nosed Monkey or Langur, Tonkin Snub-nosed Langur)

Rhinopithecus avunculus (Pygathrix a.)

Status: Critically Endangered

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, Diet, Behavior, Social Organization)
5. References

Profile

Pictures: Tonkin Snub-nosed Monkey #1 (24 Kb JPEG) (Spec. Cons. Found.); Tonkin Snub-nosed Monkey #2 (5 Kb JPEG) (Kids Ecol. Corps)

Tonkin snub-nosed monkeys measured to date have weighed about 8 kg (18 lb) (3 females) and 15 kg (32 lb) (one male). The Tonkin snub-nosed monkey is found mainly in primary subtropical lowland broadleaf forest on steep limestone hills. Its diet consists primarily of leaves (including the leaves of bamboo) and fruits. The Tonkin snub-nosed monkey is exclusively arboreal. The basic social unit is a one-male group comprised of one adult male, several females and young animals. Other males form all-male bachelor groups .

The Tonkin snub-nosed monkey is endemic to a relatively small range in northern Vietnam. In 1947 it was reported to have occurred only in forest near the Song-Koi River. Subsequently it was thought to be possibly extinct until its rediscovery in 1989. In 1993 it was reported to occur only in Tuyen Quang and Bac Thai provinces. Historical records have shown that it once inhabited 5 provinces: Tuyen Quang, Cao Bang, Yen Bai, Bac Thai and Quang Ninh.

The decline of the Tonkin snub-nosed monkey is due mainly to habitat loss from both permanent and shifting cultivation as well as hunting for meat and for use in Oriental medicine. It is also thought to have been affected by military activity in its range. More than 70% of its original habitat had been lost by 1986.

Tidbits

*** The Tonkin snub-nosed monkey is one of the world's rarest mammals.

*** This species lives in remote, mountainous areas. People in these areas are poor, and typically are unaware of the laws protecting endangered animals. (Ren et al. 1997)

*** After being briefed by biologists on threats to the Tonkin snub-nosed monkey, community-based district committees in Vietnam, composed of respected village and community leaders, banned hunting of the species in the vicinity of one of the best sites remaining in its range. (Karesh 1994)

Status and Trends

IUCN Status:

1994: Endangered
1996 - 2002: Critically Endangered (Criteria: C1, E)
2003 - 2004: Critically Endangered (Criteria: B1ab(i,ii,iii,iv,v), C1+2a(i)) (IUCN 2004)

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

2004: Occurs in Vietnam (IUCN 2004).

Population Estimates:

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

WORLD (Vietnam)
- 1992: 290 - 350 (Ratajszczak et al. 1993)
- 1994: 130 (Cao Van Sung & Pham Nhat 1994)
- 1995: 130 - 350 (Ren et al. 1997)
- 2000: About 200 (Cons. Intl. 2000)
- 2004: Less than 300 (IUCN 2004)

History of Distribution:

The Tonkin snub-nosed monkey is endemic to a relatively small range in northern Vietnam. In 1947 it was reported to have occurred only in forest near the Song-Koi River (Tate 1947). Subsequently it was thought to be possibly extinct until its rediscovery in 1989. In 1993 it was reported to occur only in Tuyen Quang and Bac Thai provinces (Ratajszczak et al. 1993). Historical records have shown that it once inhabited 5 provinces: Tuyen Quang, Cao Bang, Yen Bai, Bac Thai and Quang Ninh (Boonratana & Le Xuan Canh 1998a).

Currently, the distribution of the Tonkin snub-nosed monkey is restricted to between longitude 104 deg 54' - 106 deg 03' E and latitude 21 deg 43' - 22 deg 28' N. It may be limited to two isolated groups. (Ren et al. 1997)

Distribution Map (24 Kb JPEG) (Spec. Cons. Found.)

Threats and Reasons for Decline:

Data on Biology and Ecology

Weight:

Three adult female Tonkin snub-nosed monkeys weighed an average of 8.3 kg (18 lb); one male weighed 14.5 kg (32 lb) (Ren et al. 1997).

Habitat:

The Tonkin snub-nosed monkey is found mainly in primary subtropical lowland broadleaf forest on steep limestone hills. Plant species in its habitat include figs, dipterocarps, oaks, magnolias and maples.

The Tonkin snub-nosed monkey is found in both the Indo-Burma Biodiversity Hotspot (Cons. Intl. 2005) and the Northern Indochina Subtropical Moist Forests Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Diet:

The Tonkin snub-nosed monkey's diet consists primarily of leaves (including the leaves of bamboo) and fruits. 60 species of plants are utilized. Food choice varies with the season: young leaves are a primary component of the diet in Spring (February - May), and fruits are a primary component of the diet in Autumn (August - October). (Cao Van Sung & Pham Nhat 1994, Ren et al. 1997)

Behavior:

The Tonkin snub-nosed monkey is exclusively arboreal, usually traveling at canopy level. There are no reports of it being able to swim.

Social Organization:

The basic social unit is a one-male group. Each one-male group is composed of one fully adult male, several females and young animals. The average size of one-male groups was 15.2 individuals in one study. Extra males form all-male bachelor groups. The one-male groups frequently come together at sleeping sites and feeding trees and sometimes travel together. Bachelor groups also associate with these collections of groups. (Boonratana & Le Xuan Canh 1998, Ren et al. 1997)

References

Boonratana & Le Xuan Canh 1998, Boonratana & Le Xuan Canh 1998a, Burton & Pearson 1987, Cao Van Sung & Pham Nhat 1994, Cons. Intl., Cons. Intl. 2000, Davies & Oates 1994, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Karesh 1994, Kids Ecol. Corps, Le Xuan Canh 1997, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Ratajszczak et al. 1993, Ren et al. 1997, Simon & Geroudet 1970, Tate 1947, Spec. Cons. Found.

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Last modified: October 21, 2005;