The proboscis monkey (Nasalis larvatus) is classed as Endangered on the IUCN Red List, assessed in 2020. The reason is tied to where it lives: the flat, water-rich lowland forests of Borneo that are also the easiest land for people to clear and convert.
Why are proboscis monkeys endangered?
This species depends on mangroves, peat-swamp forest and riverbank vegetation, and it cannot survive away from them. That habitat has been lost on a large scale to oil-palm plantations, logging, shrimp farming and coastal development. The IUCN estimates the population has fallen by more than 50% over roughly the last 40 years, about three generations, leaving fewer than an estimated 7,000 mature individuals across a fragmented range. It is also listed on CITES Appendix I, the strictest level of trade protection.
Fragmentation makes things worse
As forests are cut, surviving groups end up isolated along single stretches of river, cut off from one another. Small, separated populations are far more vulnerable to disturbance, hunting and snaring, and have fewer chances to mix and stay genetically healthy.
What is being done to protect them?
Because the problem is habitat, so is the solution. Effective conservation focuses on safeguarding river corridors, restoring degraded mangroves, slowing forest conversion and keeping patches of forest connected so isolated groups can move between them. On the ground, that work includes monitoring populations, reducing hunting and snaring, managing wildlife tourism so it does not stress the animals, and rehabilitating individuals orphaned or displaced when land is cleared.
Why local teams matter most
This is slow, place-based work that depends on people who know the rivers: local rangers, community-run reserves and sanctuary teams who can respond quickly when a group is cut off or an animal is displaced. The long-term task of habitat protection sits largely with established field organisations and government reserves, which local partners support rather than replace.
The hopeful part
Where mangroves and river corridors are protected, proboscis monkeys can persist, because intact forest is something we can defend and restore. You can learn more in the proboscis monkey species guide. A gift toward habitat protection helps WARN fund the in-country rescue and ranger teams in Indonesia and Malaysia keeping Borneo's riverside forests, and the monkeys in them, standing.
Read the full Proboscis monkey wildlife guide for the facts, IUCN status and conservation context — or donate to WARN to help fund the local partners protecting this species.
