The proboscis monkey (Nasalis larvatus) or long-nosed monkey, known as the bekantan in Indonesia, is a reddish-brown arboreal Old World monkey with an unusually large nose. It is endemic to the southeast Asian island of Borneo

The proboscis monkey is assessed as endangered in the IUCN Red List of Threatened Species and listed in Appendix I of CITES. Its total population has decreased by more than 50% in the past 36–40 years to 2008 due to ongoing habitat loss because of logging and oil palm plantations, and hunting in some areas due to the species being treated as a delicacy, as well as its use in traditional Chinese medicine.[12] The population is fragmented: the largest remaining populations are found in Kalimantan; there are far fewer in Sarawak, Brunei and Sabah.[2] The proboscis monkey is protected by law in all regions of Borneo. In Malaysia, it is protected by a number of laws including the Wildlife Protection Act (federal law), the Wildlife Protection Ordinance 1998 (Chapter 26) and Wildlife Conservation Enactment 1997 (Sabah state law).