Myanmar Snub-Nosed Monkey, Rhinopithecus strykeri
MYANMAR SNUB-NOSED MONKEY
Rhinopithecus strykeri
Geographic Distribution and Habitat
The Myanmar snub-nosed monkey was only discovered in 2010 in the northeastern state of Kachin in Myanmar. Since then, smaller populations of these primates have been found in China (along the Gaoligongshan mountains), close to the Myanmar border. The species is contained geographically by the N’mai Hka River in the east and the Salween River in the west.
These snub-nosed monkeys prefer semi‐moist evergreen broadleaf forests and temperate‐cool coniferous forests, especially in the range of 8,530–10,171 feet (2,600–3,100 m) above sea level. During the winter, they move lower in elevation to avoid the snowy mountain tops.
These monkeys also tend to stay in old-growth forests unchanged by deforestation. Some researchers have noted that in China, the Myanmar snub-nosed monkey actively avoids secondary-growth forests. The habitat for the entire species is only about 1,380 square miles (3575 sq. km)—about one-third the size of Yellowstone National Park!
Their habitat can be harsh and difficult to reach, so currently there is little known about the behaviors of the ecology and behaviors of wild populations. They are also known as the Burmese snub-nosed monkey.
The Myanmar snub-nosed monkey was added as the fifth stand-alone species of the Rhinopithecus genus. The genus name comes from their unique upturned nose shape (in Greek, “Rhin” means “nose” and “pithecus” means ape). Their scientific species name, strykeri, was chosen in honor of Jon Stryker, a philanthropist who helped fund the expedition that first “discovered” the Myanmar snub-nosed monkey.
Size, Weight, and Lifespan
Males, on average, measure 22 inches (55.5 cm) in height and weigh 37.4 pounds (17 kg). Females measure 21 inches (53 cm) tall and between 20 and 26 pounds (9–11.6 kg). Their long tails measure between 25.5 and 31 inches (64.5–78 cm) long.
Their lifespan is estimated to be as long as similar species with an average lifespan of 23 years.
Appearance
Myanmar snub-nosed monkeys have the characteristic snub-nosed monkey features of an upturned nose with flared nostrils. Their pale faces are dark almond-shaped eyes and each nostril consists of two lobes, which give them their characteristic impish looks.
In Myanmar, these monkeys are called “myuk na tok the” or “Mey nwoah,” which translates to “monkey with an upturned nose.”
The bottom part of their face is dominated by a wide mouth with pale pink lips that have a splattering of black hairs.
They are covered in long bushy fur and, unlike other snub-nosed monkeys, the Myanmar species are almost completely black except for tufts of white fur on their ears, on their chin, and under their tail (the perineal area).
Their long tail is almost one and a half times the length of their body!
Males are visibly larger than females. This difference in size is an example of sexual dimorphism.
Diet
Myanmar snub-nosed monkeys are herbivorous monkeys that feed on leaves, lichen, fruits, bark, and flowers. Lichen (a symbiotic life-form made of algae and fungi) usually grow on tree bark and have similar texture. Most lichen species contain toxins that prevent other animals from eating them. However, they are an important food source for these snub-nosed monkeys, especially during the winter when other food sources are hard to find.
Like all snub-nosed monkeys, they have a multichambered stomach with microbes that digest the complex carbohydrates found in leaves and bark. Compared to other snub-nosed monkey species, the Myanmar species have higher amounts of gut enzymes that digest pectin and glucose. This is probably because they eat more fruits than other members of the genus.
Behavior and Lifestyle
Myanmar snub-nose monkeys travel by clambering, walking quadrupedally (on all four limbs), and mostly leaping or dropping from one tree-branch to another. They are exceptional climbers and leapers because they spend most of their time in trees (they are arboreal). They stick to the upper and middle canopy of the forest.
When they have to travel across large forest gaps, they leap with outstretched arms and legs to catch the branches as they fall. Sometimes they (especially males) walk bipedally (on two legs) which can make them seem taller than normal. Males will descend to the ground from time to time, while females rarely leave the canopy.
Local legend suggests that, during rainstorms, when Myanmar snub-nosed monkeys get water in their upturned noses, they sneeze the water out. This behavior is insisted on by locals who encounter the monkeys, but it has not, as yet, been documented by the scientific community.
- Myanmar snub-nosed monkeys are the only snub-nosed monkey species where adults are completely black-brown or black in color.
- In winter, they eat lichen, which can be toxic for other animals.
- Males can live alone solitarily, in bachelor groups, or as dominant males in a family.
- They have a polygynous mating system where one male will mate with many females.
- Newborns have pale blue faces and white fur.
In an environment where winters can be extremely cold, these herbivores consume as many fruits and leaves as possible to survive.
The dominant male in the troop is usually preoccupied with protecting the family. Adult males will fight to overthrow dominant males for mating rights with females, so dominant males in families must be vigilant.
The social network of snub-nosed monkeys is interesting because they have different levels of social bonding (solitary males, bachelor groups, family units) and individuals seem to frequently move between these groups. A study using satellite technology and collared golden snub-nosed monkeys (Rhinopithecus roxellana) showed that these groups come together to form relatively peaceful bands of more than 50 individuals at times. Neighboring bands rarely come in contact with each other.
The communication between Myanmar snub-nosed monkeys has not been extensively studied. Snub-nosed monkeys tend to be vocal, which is a common trait among larger primates that live in dense forests where visibility is poor. We can apply some of what we know from other snub-nosed monkey species to the Myanmar species. They use a wide range of vocal calls. These calls include soft “coos” and “whines” that they use when they are resting or foraging, loud “shrills” to greet each other, and grunts and growls when they encounter potential opponents. These calls are probably specific to males and females because it was found that females vocalize more in social settings while males vocalize louder to warn off intruders and protect the troop. Sometimes females “fight” each other from neighboring troops and make explosive grunting noises at each other. These fights are mostly ritualistic and do not result in physical contact; instead, the chorus of grunts from the larger group of females is enough to ward off intruding troops.
These snub-nosed monkeys tend to give birth around February to newborns that have pale blue faces and white fur all over their bodies. Young ones cling to their mother’s belly for at least the first year of their life. By the time the young monkeys become 2 years old, their fur changes to the black-brown of the adults. Most of the parental care is done by the females in the family.
Females become sexually mature at the age of 5 and stay with their natal family. Sexually mature males will leave the group to forage on their own or join an all-male unit (also called a bachelor group).
Snub-nosed monkeys form a multilevel society (MLS) with different social groups that come together to form breeding bands. One level is an all-male unit (AMU) that can consist of solitary males or groups of sub-adult and adult males. Another social level is groups that are dominated by one male who mates with multiple females (up to 10 individuals). These groupings are referred to as “one male, multi-female units” or OMU.
Sometimes multiple families join to form troops and multiple troops join to form a band. This most likely happens when food is abundant and there is no need to fight each other for resources. Recent studies have also suggested that bands of a large number of snub-nosed monkeys form to stay safe from predators.
Myanmar snub-nosed monkeys are capable of thriving in a harsh habitat where fruiting seasons are short, and winters can get bitterly cold. In the summer, snub-nosed monkeys play a potential role in pollinating flowers and dispersing seeds from the fruits they eat. They are among few primate species that eat lichen that are hard, are low in moisture and nutrition, and contain toxins. As they eat the lichen, they also disperse bits of the it near other trees or rocks, where new spores can form new lichen. In this manner, Myanmar snub-nosed monkeys form an integral part of this ecosystem that helps the regrowth of plant species and lichen.
Snub-nosed monkeys are potential prey for raptors like goshawks.
The International Union for Conservation of Nature lists the Myanmar snub-nosed monkey as Critically Endangered (IUCN, 2015), appearing on the IUCN Red List of Threatened Species.
Wildlife Biologists estimate that there are only 490–620 Myanmar snub-nosed monkeys left in the wild!
Despite the government’s prohibition on hunting, scientists have encountered hunters who have shot or trapped Myanmar snub-nosed monkeys. In Myanmar and China, hunting primates has a long history, with the bones and skulls being used in traditional medicines and rituals. Local trading of primate meat and body parts is also profitable for hunters. The demand for exotic animals, such as rare snub-nosed monkeys, increases as economic development improves and more people can afford them. Unfortunately, with the economic growth, hunters also have access to automatic firearms that can increase their hunting success. These factors can have devastating effects on the pockets of Myanmar snub-nosed monkeys that live close to villages.
Forest logging and charcoal production pose serious threats to wildlife along the China-Myanmar border, where removing trees can lead to landslides and soil erosion. Not only does the deforestation here eliminate primate habitat, but makes it impossible for the ecosystem to recover. The building of roads to access logging sites adds to the habitat destruction and fragmentation of the forest.
Researchers are also concerned about growing air pollution, which is a threat to sensitive lichen, which is an important winter food for snub-nosed monkeys.
The 2021 Myanmar military coop has unsettled national conservation policies and foreign organizational support as foreign scientists and workers were forced to leave the country. This disruption in conservation work and funding puts the survival of the already endangered snub-nosed monkey at greater risk.
The Myanmar snub-nosed monkey is listed in Appendix I of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
They are given the highest level of protection against international trade. Hunting snub-nosed monkeys is illegal in China and Myanmar. Enforcing the laws in remote areas that are difficult to patrol has led to illegal hunting activities. As a protection measure, the governments have increased the number of forest rangers in the area to put pressure on hunters. China, at least, has continued funding and research on Myanmar snub-nosed monkeys for a decade.
The Myanmar government has worked with Fauna Flora International (FFI) and local communities to mark out a protected area to conserve biodiversity with the goal of saving the snub-nosed monkeys from extinction.
- Chi, M., Zhi-Pang, H., Xiao-Fei, Z., Li-Xiang, Z., Wen-Mo, S., Scott, M.B., Xing-Wen, W., Liang-Wei, C. and Wen, X., 2014. Distribution and conservation status of Rhinopithecus strykeri in China. Primates, 55, pp.377-382.
- Geissmann, T., Momberg, F. & Whitten, T. 2020. Rhinopithecus strykeri. The IUCN Red List of Threatened Species 2020: e.T13508501A17943490. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T13508501A17943490.en. Accessed on 24 November 2023.
- Geissmann, T., Lwin, N., Aung, S.S., Aung, T.N., Aung, Z.M., Hla, T.H., Grindley, M. and Momberg, F. (2011), A new species of snub-nosed monkey, genus Rhinopithecus Milne-Edwards, 1872 (Primates, Colobinae), from northern Kachin state, northeastern Myanmar. Am. J. Primatol., 73: 96-107. https://doi.org/10.1002/ajp.20894
- PBS blog. https://www.pbs.org/wnet/nature/blog/featured-creature-black-snub-nosed-monkey/
- Meyer D, Momberg F, Matauschek C, Oswald P, Lwin N, Aung SS, Yang Y, Xiao W, Long Y-C, Grueter CC, Roos C. (2017): Conservation Status of the Myanmar or Black Snub-nosed Monkey Rhinopithecus strykeri. Fauna & Flora International, Yangon, Myanmar; Institute of Eastern-Himalaya Biodiversity Research, Dali University, Dali, China; and German Primate Center, Göttingen, Germany
- Qi, X.-G., Garber, P.A., Ji, W., Huang, Z.-P., Huang, K., Zhang, P., Guo, S.-T., Wang, X.-W., He, G., Zhang, P., Li, B.-G., 2014. Satellite telemetry and social modeling offer new insights into the origin of primate multilevel societies. Nature Communications 5, 5296.. https://doi.org/10.1038/ncomms6296
- Xi, L., Han, J., Wen, X., Zhao, L., Qin, X., Luo, S., Lv, D., Song, S., 2023. Species variations in the gut microbiota of captive snub-nosed monkeys. Frontiers in Endocrinology 14.. https://doi.org/10.3389/fendo.2023.1250865
- Yang, Y., Groves, C., Garber, P., Wang, X., Li, H., Long, Y., Li, G., Tian, Y., Dong, S., Yang, S. and Behie, A., 2019. First insights into the feeding habits of the Critically Endangered black snub-nosed monkey, Rhinopithecus strykeri (Colobinae, Primates). Primates, 60, pp.143-153.
- Yang, Y., Youlatos, D., Behie, A.M., Belbeisi, R.A., Huang, Z., Tian, Y., Wang, B., Zhou, L., Xiao, W., 2021. Positional behavior and canopy use of black snub-nosed monkeys Rhinopithecus strykeri in the Gaoligong Mountains, Yunnan, China. Current Zoology.. https://doi.org/10.1093/cz/zoab071
Written by Acima Cherian, November 2023