Numbers of proboscis monkeys in Borneo have fallen dramatically in the last 40 years primarily as a result of habitat loss (4). Vast areas of the native rainforest have been cleared for timber and for the construction of oil-palm plantations, which now constitute one of Malaysia's top exports (4). Proboscis monkeys do not adapt to degraded habitat and recent technical advances have meant that even mangrove swamps may now be logged (4). Hunting is also a threat to the survival of this species; their propensity to gather in large groups on the river's edge makes these monkeys easy targets (4).
The proboscis monkey is protected by law (4), and is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), banning international trade (3). This species is found in at least a dozen protected areas (2). Recently, a vital area of wetland in Sabah has been designated as a sanctuary for a wide range of endangered species such as Asian elephants (Elephas maximus) and orang-utans (Pongo pygmaeus) as well as proboscis monkeys; this area is the Kinabatangan Wildlife Sanctuary (4). However, even this corridor is currently fragmented by plantations, which proboscis monkeys cannot cross (4). The protection of remaining tracts of contiguous habitat is therefore vital for the survival of this unusual looking monkey.