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Flora & Fauna
Mammals - Primates

The rainforests of Borneo are home to two species of ape and eight species of monkey. (In case you are wondering what the difference is, apes do not have tails.) Collectively, they are all known as primates. Five which can be seen in Sarawak's national parks and wildlife santuaries are:

  • Proboscis Monkey (Nasalis lavartus) - The big nose and pot-belly of these big monkeys gave rise to their local name, "Dutchman", after the first white people they saw.
  • Orang-utan (Pongo pygmaeus) - The great red ape itself, only found in Borneo and a small area in Sumatra.
  • Silver Langur - Gentle and shy small leaf-eating monkeys.
  • Long-Tailed Macaque (Macaca fascicularis) Macaques are found across Southeast Asia, and adapt quite well to cohabiting with humans - and will get up to all sorts of monkey business with your bags if you have food in them.
  • Bornean Gibbon (Hylobates mulleri) - The joyous whoop-whooping chorus of gibbons singing out in the morning is one of the classic Borneo jungle sounds.
Flora & Fauna
> Fores Types
> Primates
Trek Locations
> Bako NP
> Gunung Gading NP
> Kubah NP & Matang
> Lambir Hills NP
> Mulu NP
> Niah NP
> Santubong
> Tanjung Datu NP
Proboscis Monkey

Scientific name: Nasalis larvatus

Local names: orang belanda (Malay)

Legal status: Totally Protected

Description

After the orang-utan, the proboscis monkey is the best known primate of Sarawak. It is easy to understand why: the huge nose (which their English and Latin names refer to) and large bellies of the males make them instantly recognisable, and give them a somewhat comical appearance. (The Malay name "orang belanda" literally means "Dutchman" - not entirely complimentary to the Dutch!) Proboscis monkeys are also the largest of the monkey species in Sarawak, with males weighing about 20kg. The females are about half this size, and have tiny little noses. It's not certain what purpose the large male nose serves, but it is thought that it may be attractive to the females (just like people - or maybe not!).

Proboscis monkeys live near the water, mainly in mangrove and coastal riverine forests. These forest types only occur in very small and isolated patches, hence the rarity of the monkeys. Although they live mainly in the trees, proboscis monkeys are excellent swimmers, and even have slightly webbed hind feet!

Proboscis monkeys eat mainly seeds, non-sweet fruit and young leaves. This diet explains the large stomachs, which are compartmentalised like cow's stomachs, allowing bacteria to break down the tough foods. The poor quality of the food also means that proboscis monkeys have to move around quite a lot to find food. During the wet season, when there is less fruit in riverine forest, they are more likely to come down into the mangroves to look for food.

Proboscis monkeys live in loose social groups of 8 to 10 individuals. They are found in two types of group: an adult male with a harem of females and children; and all-male groups. But different groups meet at different times, and individuals move between them.

Best places to see

Unlike the orang-utan, which also occur in northern Sumatra (Indonesia), proboscis monkeys are only found in a few scattered locations, all in Borneo. And the best of these locations to see them is Bako National Park, in the area around the park headquarters, in the early morning and at dusk. Check with the staff about where the most recent sightings have been - if you're lucky, you may not have to walk more than 50m from your cabin door!

You'll usually hear proboscis monkeys before you see them - crashing around in the canopy and issuing loud honking ("Ngonk!") and grunting sounds. The males, being larger and more brightly coloured, are easier to spot - particularly their red backs and long white tails, which hang straight down.

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