These primates belong to a group of monkeys named odd-nosed colobines. They are considered one of the largest colobines in the world. Their body and head fur are mostly a bright orange/reddish brown colour, with grey arms, legs and belly. The large nose where the monkey gets its name, is only seen on males, however the female does have an above average nose for a primate. They are also known for their potbellies.
They inhabit waterside forests, and can only be found on the island of Borneo. Along with the orangutan these primates are favoured by eco-tourists, where many intrigued travelers watch these monkeys from riverboats and canoes.
Their diet consists of leaves, seeds, fruits, and occasionally small insects. A typical group would contain one male and 2-3 females. However, groups sizes can range from 2- 25 and bachelor groups are occasionally formed. They can rest up to 75% of the day and can live up to 14 years.
Females have a gestation period of 5 months. They will compete with each other to mate with males that have the largest noses. There are theories that the females prefer the vocalisations from males with larger noses as they can be louder and resonate further — and the bulbous nose of a proboscis has been sexually selected by the females.
To cross rivers they sway from branches to build up momentum to hurl themselves across to the other side. Although, if the river is too wide, they will dive from treetops into the water but usually ending in a belly-flop. Proboscis monkeys are proficient swimmers having partially webbed feet and hands and can swim underwater for up to 20 meters.
This species is considered endangered, with palm-oil plantations being a major threat through forest clearance and fragmentation. In the last 40 years proboscis populations have dropped by nearly 50%. The species is also threatened by hunting and is used in traditional Chinese medicine. The proboscis monkey is protected throughout Borneo by law such as the Wildlife Protection Act. Large portions of its remaining habitat are also protected.
Eco-tourism is playing a major part in driving the protection of these monkeys and their habitat, as it creates income for the locals and boost the economy giving an incentive to conserve this species. World Land Trust (WLT) also have projects within Borneo purchasing land to create important wildlife corridors to connect fragmented forests. World Land Trust is an “international conservation charity that protects the world’s most biologically significant and threatened habitats acre by acre.” WLT funds the creation of reserves and provides protection for wildlife. Partnerships are developed with local organisations engaging and supporting the local community.
Written by Emily Elmer – Wildlife Conservation Today Contributor