The Proboscis Monkey or bekantan (Nasalis larvatus) is a long-nosed primate that can only be found in the tropical forests of Borneo. Its unique physical traits make it stand out among other primates, while its role in maintaining the balance of mangrove and swamp ecosystems makes it highly important for the preservation of Kalimantan’s biodiversity.
In addition, the Proboscis Monkey has cultural value that is closely tied to the identity of local communities, making it an iconic species of Borneo known worldwide. Interestingly, there is still much about the bekantan that people do not know, from its social behavior to the threats it faces in the wild.
To understand more about this unique primate, let us begin with a fundamental question: What is the Proboscis Monkey?
What is the Proboscis Monkey?
The Proboscis Monkey is known locally as bekantan in Indonesia. Its scientific name, Nasalis larvatus, refers to its distinctive facial feature—its long nose, especially prominent in adult males. This nose is not just a physical trait but also serves a role in vocal communication and in attracting females.
This primate is endemic to Borneo, meaning it can only be found on this island. They inhabit areas in Kalimantan, Sabah, and Sarawak.
Proboscis Monkeys prefer to live in mangrove forests, swamps, and riverine forests because these habitats provide their main food sources as well as easy access to water.
In addition, they are recognized by their reddish-brown fur with lighter undersides. Their body length can reach 60–75 centimeters, with tails nearly as long as their bodies, which helps them balance when moving through the trees. This unique combination of physical characteristics and specialized habitats makes the bekantan one of the most easily recognizable and fascinating primates to study in Southeast Asia.
Read also: The explanation of 'mystery monkey' found in Sabah, Malaysia
Behavior and Lifestyle of the Proboscis Monkey
The Proboscis Monkey lives in groups with a fairly complex social structure. A typical group consists of a dominant male, several females, and their offspring. There are also bachelor groups made up of young males before they establish their own groups.
Their main diet consists of young leaves, fruits, seeds, and plant shoots. They have a unique digestive system with a large, chambered stomach capable of fermenting fiber. Besides being skilled climbers, Proboscis Monkeys are also excellent swimmers. They often cross rivers using a dog-paddle style or by leaping directly from trees into the water.
Why is the Proboscis Monkey So Special?
The primary uniqueness of the Proboscis Monkey lies in the long nose of adult males, which can grow more than 10 centimeters. This nose amplifies vocal calls, making it easier to attract females or intimidate rival males.
In addition to its nose, the Proboscis Monkey is also known for its distinctive “pot-bellied” appearance caused by its specialized digestive system. Culturally, the bekantan is the official mascot of South Kalimantan Province, symbolizing local identity and pride.
Beyond these features, the Proboscis Monkey is also special due to its adaptation to aquatic environments. Unlike most other primates, it is an excellent swimmer thanks to webbing between its fingers and toes. This allows them to leap from trees into rivers and swim across strong currents, a skill that adds to its reputation as one of the most unique primates in the world.
Read also: Not Just the Amazon: The Role of Borneo and ASEAN’s Rainforests
Threats to the Survival of the Proboscis Monkey
Unfortunately, the Proboscis Monkey faces serious threats today. Habitat loss due to deforestation, conversion of land into palm oil plantations, and infrastructure development has caused their population to decline. They are highly dependent on mangrove and swamp forests, which are shrinking at an alarming rate.
Illegal hunting also poses a threat. Although legally protected, some individuals are still captured for the pet trade or killed due to human-wildlife conflicts. Climate change, which impacts riverine and swamp ecosystems, further worsens their situation.
Why Should We Protect the Proboscis Monkey?
Protecting the Proboscis Monkey also means preserving the mangrove and swamp ecosystems that are vital for many other species. They play a role as seed dispersers and vegetation regulators, helping to maintain forest balance. If they disappear, the ecological chain in Borneo will be disrupted.
Beyond ecological importance, the presence of the Proboscis Monkey contributes to Kalimantan’s ecotourism appeal. Many local and international tourists visit specifically to see this iconic primate. Therefore, protecting the species also supports local economies through sustainable tourism.
Read also: The Bornean Orangutan: Asia’s Endemic Great Ape
Conservation Status of the Proboscis Monkey
According to the IUCN Red List, the Proboscis Monkey is classified as Endangered. Its population is steadily declining, with estimates suggesting only around 100,000 individuals left in the wild. Without serious conservation efforts, this number will continue to fall.
The Indonesian government has granted protected status to the bekantan through legislation. Conservation organizations and local groups are also active in rehabilitation efforts, community education, and campaigns to safeguard mangrove forests, which are their primary habitat.
Preserving the Proboscis Monkey, Protecting the Icon of Borneo
The Proboscis Monkey is not only unique because of its long nose but also because it symbolizes the biodiversity and cultural identity of Borneo. Its existence reflects the immense value of mangrove and swamp ecosystems, which serve as home to countless species. If the bekantan disappears, Borneo will lose one of its most iconic natural treasures.
Through collective support, we can safeguard the Proboscis Monkey. This includes supporting sustainable ecotourism, reducing consumption of products that harm habitats, and advocating for wildlife conservation. Let us join hands in protecting the Proboscis Monkey, because every small step we take will help ensure this long-nosed primate remains part of Borneo’s tropical forests for generations to come.
References
- National Geographic. Proboscis Monkey. https://www.nationalgeographic.com/animals/mammals/facts/proboscis-monkey
- Scheuman, L. J (2024). Why the Proboscis monkey has the largest nose of any primate. https://www.oneearth.org/species-of-the-week-proboscis-monkey/
- Setyawati, Dyah (2023). Bekantan (Nasalis larvatus). https://primata.ipb.ac.id/bekantan-nasalis-larvatus/
