On the Brink: Extinction Risks for the Tonkin Snub-Nosed Monkey

Figure 1: Four Tonkin Snub-Nosed Monkeys (Photo by Lekhac Quyet)

This blog has previously addressed the importance of nonhuman primate conservation.  This point has been highlighted by a series of endangered primate profiles written by the blog author and guest authors comprised of her students (a sample exists here, here, and here).  Today’s blog post continues with this vein of inquiry by addressing a critically endangered primate species that was previously believed to have been extinct until its rediscover a few decades ago.  This rediscovery has earned it the label of a “Lazarus” species, but this is a misnomer because it remains on the brink of extinction presently.  This blog post will discuss the Tonkin Snub-Nosed Monkey (Figure 1) and the difficulties in preserving this particularly nonhuman primate species.

 

The Tonkin Snub-Nosed Monkey is the only snub-nosed species located in Vietnam. The other three types of snub-nosed species exist in nearby China.  As of 2019 it is estimated that there are no more than 130 individuals left in the wild, which are dispersed into very small groups throughout isolated conservation areas.  This presents a serious problem in encouraging population growth due to limited mate options among the troops. 

 

Tonkin Snub-Nosed Monkies are arboreal, diurnal (active during the day) primates.  They are characterized as being slender, large bodied, and sexually dimorphic species.  The males are doubled the size of females.  Both are characterized by black and white bodies with small patches of brown fur on the back of their heads and orange fur on their throats.  Their faces have bald patches characterized by blue skin around their eyes and blue-black skin around their mouths. 

 

The Tonkin Snub-Nosed Monkeys are consumers of a variety of hard plants that various other forest dwelling species do not consume, in large part due to the difficulties in chewing and digesting the plants and the poisonous nature of their consumption.  This means that the Tonkin-Snub Nosed Monkeys have minimal competition in the consumption of the leaves, stems, fruits, and seeds they consume, which is a positive aspect of their existence.  It also means that they cannot be easily removed from their home environments due to their specialized diets. 

 

Tonkin Snub-Nosed Monkeys have been observed existing in primate social organizations defined by either one male or multimale groupings.  It is unclear if this is a natural grouping or if this is one that has developed out of a lack of options (due to small troop sizes).  What is also troubling is the lack of survivor behaviors among these primates.  Typically, species that are heavily hunted by humans develop an aversion to them, but this is not the case with Tonkin Snub-Nosed Monkeys.  They show little to no fear of humans, demonstrated by them not running away when they encounter humans.  This leads to them being easily hunted.  Villagers have admitted to hunting the Tonkin Snub-Nosed Monkey, although it is unclear why.  As hunting contributes to the decline in their populations this behavioral pattern is concerning, but it is not one that humans can change.

 

The human endangered factor that is proving to be the biggest factor in reducing the Tonkin Snub-Nosed Monkeys’ ability to survive and grow its populations is forest fragmentation and deforestation.  The forests these primates exist in are being cut down to make room for agricultural activities, largely activities used to produce crop exports (e.g., cardamon, potatoes, and bananas).  As the Tonkin Snub-Nosed Monkey is a largely arboreal primate, the forest fragmentation disables their ability to travel, limiting their opportunities to acquire new mates and produce more offspring.  Several attempts to restore the forested regions have been made, but they have largely been unsuccessful.  Also, the attempts to conserve the forests where the Tonkin Snub-Nosed Monkey reside have failed because the populations disappear, rendering the conservation of that area mute. 

 

Despite these challenges scholars and conservationists continue their efforts to document and preserve this species.  Due to their small size there is very little precisely known about them, but it is clear based on the extinction of other species across the world that the extinction of the Tonkin Snub-Nosed Monkey will probably have a negative impact on its habitat.  This is just one reason why these conservation efforts continue despite the challenges previously and currently faced.

 

References

James, N. (2017). Movement and Socioecology of the Tonkin Snub-nosed Monkey and recommendations for future conservation. Oxford Brookes University.

 

Le, X.C. and R. Boonratana. 2006. A conservation action plan for the

Tonkin snub-nosed monkey in Viet Nam. Hanoi/New York: IEBR/PCI.

 

Nguyen, N. (2000). A survey of Tonkin snub-nosed monkeys (Rhinopithecus avunculus) in Northern Vietnam. Folia Primatologica, 157-160.

Quyet, L. K., Nguyen, A. D., Tai, V. A., Wright, B., & Covert, H. H. (2007). Diet of the Tonkin snub-nosed monkey (Rhinopithecus avunculus)in the Khau Ca area, Ha Giang Province, Northeastern Vietnam. Vietnamese Journal of Primatology, 75-83.

Schwitzer, C., Mittermeier, R. A., Rylands, A. B., Chiozza, F., Williamson, E. A., Byler, D., . . . McCabe, G. (2019). PRIMATES IN PERIL: The world’s 25 most endangered primates 2018-2020. Washington, D.C.: IUCN SSC Primate Specialist Group, International Primatological Society, Global Wildlife Conservation, and Bristol Zoological Society.