Tonkin Snub-Nosed Monkey

Rhinopithecus avunculus
Dollman’s snub-nosed langur, Dollman’s snub-nosed monkey, Tonkin snub-nosed langur
The Tonkin snub-nosed monkeys are easily recognizable primates, exhibiting a rather unusual appearance. Their eyes are surrounded by faint, blue colored stripes. The ears are tufted, while the nose is flat and turned upward. They have a wide and flattened face with thick, pink lips. There is no information on life expectancy of this species. However, other colobine monkeys are known to live around 29 years in captivity and 20 years in the wild. The Tonkin snub-nosed monkeys are the largest primates, found in Vietnam. Meanwhile, this species is presently among the most endangered primates around the globe, which was thought to have gone extinct until 1989, when it was found again.
250

population size

20-29 yrs

Life span

8-14 kg

Weight

51-65 cm

Length

Disrtibution

Tonkin snub-nosed monkeys are native to Vietnam, occupying the northern parts of the country. The original range of this species covered the area east of the Red River. During the last decades, these animals have lost a significant part of their range. Currently, they are found in tiny, scattered areas in the provinces of Tuyen Quang, Bac Kan, Ha Giang and Thai Nguyen. Tonkin snub-nosed monkeys are most commonly found in primary forests. Overall, these primates prefer subtropical evergreen forests with karst limestone hills and mountains.

Habits and lifestyle

Tonkin snub-nosed monkeys display strong social habits, forming groups that consists of a single adult male and numerous females with their young, which socialize, feed, sleep, and travel together. These groups occasionally divide into smaller sub-groups as well as unite to in bigger super-groups. Additionally, males are known to gather into all-male units. Tonkin snub-nosed monkeys are diurnal creatures, sleeping at night and being active by day. They sleep on lower tree branches near mountain slopes, which serve as barriers against cold winds. Their habit of splitting into smaller groups and mixing with other groups suggests that these animals are non-territorial. When travelling among trees, they walk, leap and climb, using all of their four legs. Adult individuals of this species spend their time hung from tree branches, leaping from tree to tree as well as arm swinging.

group name

troop, barrel, cartload, tribe, wilderness

Diet and nutrition

Tonkin snub-nosed monkeys are herbivores (folivores and frugivores), they generally consume leaves, fruits, flowers and seeds.

Mating habits

Tonkin snub-nosed monkeys are polygynous, which means that one male mates with multiple females. The mating behavior and habits of this species is insufficiently explored due to small overall population and lack of observations in the wild. However, gestation period is known to last for 200 days, yielding 1 - 2 infants. Females produce young during the spring and summer months. Duration of nursing period is unknown. The age of reproductive maturity is 7 years old in males and 4 years old in females.

Mating behavior

Pregnancy duration

200 days
female

female name

male

male name

infant

baby name

1-2 infants

baby carrying

Population

Population Trend

Population status

ne
dd
lc
nt
vu
en
cr
ew
ex

Population threats

This species has lost a significant part of its original range due to large-scale deforestation and continuous hunting. As a result, Tonkin snub-nosed monkeys are now found only in 5 isolated populations. Currently, these monkeys still suffer from destruction, degradation and fragmentation of their habitat. Throughout their range, they face massive deforestation for agricultural land, development, road construction, both legal and illegal tree felling, gold mining as well as production, using non-timber materials. Nevertheless, the primary threat to the population of this critically endangered species is hunting, although its meat is known to be bad-testing. However, this monkey is often killed when seen in the wild, being used in food and traditional medicine.

Population number

According to the IUCN Red List, the total population of Tonkin snub-nosed monkeys’ is approximately 250 animals, inhabiting their known range (the total range of this species is thought to be unknown). Overall, the species’ numbers are decreasing today, and the animal is classified as Critically Endangered (CR) on the IUCN Red List.

Ecological niche

These primates are known to maintain herbivorous diet, thus controlling plant communities of the local ecosystem. In addition, this diet allows them to act as important seed dispersers of the plants they use.

Fun facts for kids

  1. Tonkin snub-nosed monkeys communicate with each other through a system of vocalizations. The most commonly used call in this species is the "hiccup" or “huu-chhhk” sound, which is used in everyday communication as well as serves as an alarm call, helping warn group members of potential threats. They also use vocalizations when travelling or detecting a resource.
  2. This monkey is among the rarest mammals around the globe.
  3. Monkeys are known to spend a significant amount of their active time mutual grooming, during which they usually picking out coats of one another to find and remove bugs.
  4. Aggression is displayed through a wide variety of ways such as yawning, head bobbing, grinning or pulling a lip.
  5. Monkeys are known to be very smart mammals. Moreover, the IQ of these highly intelligent primates is as high as 174.
  6. Monkeys differ from apes by having tails.
  7. Tonkin snub-nosed monkeys belong to the group of Old World monkeys, members of which exhibit 32 teeth, while New World monkeys usually possess 36 teeth.