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  นิตยสาร สารคดี: ฉบับที่ ๒๒๐ เดือนมิถุนายน ๒๕๔๖ ISSN 0857-1538  

Proboscis Monkeys of Borneo

  Story & Photos: Kriangkrai Suwannapak
 
Click to Bigger     Sukua is a small village located near the mouth of Kinabatangan River, the longest in the Malaysian Sabah state on Borneo Island. With areas along the river designated nature reserve and sanctuary, Sukua is a favorite hangout place for nature lovers and wild animals alike. Among the diverse fauna found here are strange looking proboscis monkeys, unique to Borneo Island.
    Proboscis (meaning tube or trunk) monkey is so named for its long trunk-like nose. This type of monkeys caught biologists' attention when it had been discovered that they could not thrive in human-controlled environments. By the time biologists figured out that the monkeys could take neither sweet fruits-typical food of other monkeys-nor anti-biotics, many lives had been lost.
Click to Bigger      What is different about proboscis monkeys is their unique digestive system which relies on bacteria to do the digesting, a system similar to that of bovine animals. Their main diet consists mainly of young leaves and sometimes fruits or seeds that are not sweet.
    One might wonder how proboscis monkeys eat when their mouth is covered by the trunk-like nose. Luckily their nose is not rigid but rather limp. They can swing the nose left or right depending on which hand they use to put leaves into their mouth.
Click to Bigger     Since it has no function other than being the external air passage, why does the nose have to be this long? The most plausible explanation available is that the long dangling nose, which is found only in adult males, is considered attractive to female proboscis monkeys. Because males with sexy well-hung noses have a better chance of mating this feature becomes dominant in successive generations
    But future survival of the proboscis monkeys might be at stake. The biggest threat to the population is not their natural predators but rather the loss of their habitat to rapidly encroaching palm plantations, mines and shrimp farms. The proboscis monkey is merely one of many species endemic to Borneo that are declining in number...