The proboscis monkey (Nasalis larvatus) is an iconic primate species found only on the Island of Borneo. Populations of this species are found in the Malaysian states of Sabah and Sarawak, the Indonesian province of Kalimantan, and Brunei. Throughout its range the proboscis monkey is also known by various local names such as kera belanda, monyet belanda, monyet probosis and orang belanda. In Sabah, proboscis monkey is known as bangkatan.

Proboscis monkeys have reddish-brown fur on the head, face, shoulders and upper back. Their fur on the lower back and stomach are grey, feet are yellowish-white while their throat and neck are white (Sjahfirdi & Noviandini, 2018). The tail is long (55-67 cm) and white or greyish in colour. The body length of adult male is about 56-72 cm with an average weight of 20 kg whereas adult female body length is about 55-62 cm and weight about 10 kg (Britannica, 2020; Sha et al., 2011). Adult males, especially dominant animals, have much larger and longer noses than females. Females have short pointy witch-like noses. Infants are born with small snubby noses and dark blue faces. Their noses gradually will develop into their signature larger noses and the dark blue face slowly turns greyish and then pink, like adults when they reach maturity (Sha et al., 2011).

Proboscis monkeys are threatened by the conversion of riparian and coastal mangrove habitats to plantations which may cause habitat fragmentation and consequently lead to a local extinction.