Proboscis Monkey Report Text by Chelin Kusuma Aprida

(Adopted from: https://goo.gl/6ky7Yl)

PROBOSCIS MONKEY
By Chelin KusumaAprida
The proboscis monkey or Nasalis larvatus, known as Bekantan in Indonesia, is a type of long-nosed monkey with bulging stomach. This animal is a native of Borneo that is often found in riverside, mangroves, wetlands and coastal lowland forests in Brunei, Kalimantan (Indonesia), Sabah and Sarawak (Malaysia).
Proboscis monkey adult has reddish-brown fur around the head and shoulders, and gray fur around the arms, legs, and tail. Their tails have the same length as their body size. Proboscis monkey's face is red and they have brown eyes, and small ears. Physically, male's body is larger than female with a height of 75.5 cm and weight of 23 kg, while female with a height of 62 cm and weight of 11 kg.
The main characteristic of proboscis monkey is their large nose that hang beyond their mouth. Male has large nose like proboscis expands that make them so-called proboscis, while female's nose is not. Male uses their large nose to attract female. Female prefers male with larger nose as a partner. Their nose will swell and turn red when they are happy or angry. Proboscis monkey also has a call that sounds like the car horn. Their calls sound very loud as a warning when they sense danger. Their nose serves as a resonator when they call.
The other characteristic of proboscis monkey is their bulging stomach. Their stomach has bacteria that help to digest the leaves they eat and help to neutralize toxins in certain leaves. It has a weight of one-quarter of their body weight and it makes them look like pregnant. Proboscis monkey is diurnal or active during the day. They search for food in the morning, rest during the day, and search for food again before evening. Proboscis monkey is frugivorous and folivorous. They consume unripe fruits, seeds, leaves and sometimes insects. 95 percent of the food they eat is mangrove tree leaves. They prefer to eat the ripe leaves.
This species spends most of their time in trees by jumping from branch to branch. They live in a group of between 10 to 32 monkeys and led by a strongest male. Their group consists of an adult male, several females and their offspring. Young male of proboscis monkey will leave the group where they were born at the age of 18 months. They will join a group with all male. Proboscis monkey is not a territorial animal so that they can live together in one place with another group of proboscis monkey.
Proboscis monkey can swim well like a dog because they have a membrane on the sidelines of their toes. They are sometimes seen swimming across the river and from one island to another. Proboscis monkey lives depend on the habitat that borders the river and they usually do not move farther than 600 m from the river or waterway. Proboscis monkey avoids open areas and human settlements. They sleep in trees with thick branches that are above the water to protect themselves from predators.
Female of proboscis monkey's gestation period is about 166 days or 5-6 months and only gives birth to one child in one season. They usually give birth at night. Young proboscis has bluish face and black feather, and the color will change around 3-4 months to show that they have grown. Female protects and feeds her child after birth. Young proboscis will be with their mother until the age of 4-5 years. They live up to 20 years.
Proboscis monkey's life protected by mangrove habitat that is not habitable for humans. Due to illegal logging and the technology in cutting down the mangrove trees is increasingly advanced, now their habitat disappeared. Their population is declining day by day. In 1987, there were about 260,000 of them on Borneo Island, but in 2008, the number dropped dramatically, and there are only about 25,000 of them. It caused by illegal logging, forest fires and oil palm plantations. By IUCN Red List, proboscis monkey puts in a category of "Endangered" animal (Threatened Extinction) since 2000. They are also listed on CITES as Appendix I (should not be traded internationally). Their main predators are humans, leopards and pythons.
Proboscis monkey is used as a mascot by South Kalimantan province and Dunia Fantasi Ancol (Ancol Fantasy World) because of their uniqueness. But it is ironic to know that they are already endangered and we can't do anything to save them.







References
Meijaard, E., Nijman, V. & Supriatna, J. 2008. Nasalis larvatus. The IUCN Red List of Threatened Species 2008: e.T14352A4434312. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T14352A4434312.en. Downloaded on 30 April 2016.
Gron KJ. 2009 February 25. Primate Factsheets: Proboscis monkey (Nasalis larvatus) Taxonomy, Morphology, & Ecology . http://pin.primate.wisc.edu/factsheets/entry/proboscis_monkey/taxon . Accessed 2016 June 21.
Dunia Fauna. (nd). Bekantan (Nasalis Larvatus). http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T14352A4434312.en. Accessed 2016 June 21.