Silvery Gibbon

Silvery Gibbon Fact File

Hylobates moloch

Credit: Copyright. The Animal Facts.

Weight

5.5kg

(12lbs)

Length

45-64cm

(18-25in)

Lifespan

Wild 35 years

Captive 50 years

Diet

Omnivore

Fruit, Insects, Leaves

Conservation Status

IUCN

Endangered

The silvery gibbon is named for the coat of dense silver fur which covers most of their body and gives them a fluffy look.

An alternative name for this species is the Javan gibbon, a reference to their range with the species found exclusively on the island of Java.

These animals will live in a family unit made up of the adult pair which are monogamous and remain together for life. Young remain with their parents for the first few years of their life learning the skills they need to survive.

Unfortunately they are increasingly threatened by habitat loss and fragmentation along with collection for the pet trade.

Read on to learn more about these magnificent mammals.

Appearance

What does the silvery gibbon look like?

The name of the silvery gibbon is taken from the fur across its body which is mostly silver grey in color. On the head they have a cap of dark blue-grey fur. Their is pale fur on the eyebrows, cheeks and beard.

These animals appear fluffy as a result of their long, dense fur.

To assist with brachiating these animals have long forearms and limbs.

Their eyes are colored brown with a small, round, black pupil.

They are considered to be a lesser ape and as a result do not have a tail.

An average silvery gibbon will reach a length of 45-64cm (18-25in) long with a weight of 5.5kg (12lbs). Males and females have a similar appearance.

Diet

What does the silvery gibbon eat?

The silvery gibbon is an omnivore. They feed on fruit, leaves, nuts, nectar and insects such as grubs. Over 125 plants have been recorded as part of their diet.

As much as 60% of their time is spent foraging.

Credit: Under License from JumpStory

Range

Where can you find the silvery gibbon?

Asia is the native home of these primates. The silvery gibbon is restricted to the island of Java in Indonesia. Most of their range is in the west but some occur in the center of the island.

They are the only species of gibbon which occurs on the island of Java.

Habitat

What kind of environment does the silvery gibbon live in?

They make their home in tropical rainforests.

These animals are considered to be strictly arboreal and it is rare to see them on the ground.

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Reproduction

How does the silvery gibbon produce its young?

There is no defined breeding season and females may enter estrus at anytime of the year.

Pairs of silvery gibbons are monogamous and remain together for life.

A single offspring is born after the 210 day gestation period. At birth the young have almost no hair and are colored pink.

Young remain in their birth group for an extended period of time to learn the skills they will require to care for their young. They also learn how to forage, socialize and survive generally.

Sexual maturity is reached between 5 and 7 years old.

Females have a 2-3 year gap between births.

Behavior

What does the silvery gibbon do with its day?

Silvery gibbons live in a family unit made up of a monogamous, adult pair and their young. Groups may total up to six members.

The group will maintain a territory which they prevent other non-related gibbons from entering. Some gibbons do not hold a territory and are referred to as floaters.

To defend the territory against threats the family will produce a call to defend it. Unlike other gibbon species the male and female will not make their dueting call. Females are more dominant vocalists while the males only join in occasionally.

Silvery gibbons will move through the trees using a unique form of locomotion known as brachiation which is used only by gibbons. During this they swing their arms from branch to branch.

They are active by day when they will forage. These animals do not stop feeding during the heat of the day instead they just move to lower levels of the forest.

Silvery (Javan) Gibbon (Hylobates moloch)

Credit: Copyright. The Animal Facts.

Predators and Threats

What is impacting the survival of the silvery gibbon?

Natural predators of the silvery gibbon include birds of prey.

Numbers of this species are declining in the wild. They are under significant threat as a result of habitat loss and fragmentation. The total population is thought to be less than 4,000 and no individual sub-population has more than 100 members.

They are the subject of hunting to supply the pet trade. Some are also taken for food.

A number of sub-populations are believed to have been removed.

Conservation efforts exist in Java which are seeking to return former captive gibbons to the wild.

Quick facts

The silvery gibbon is also known as the Javan gibbon or Moloch gibbon. Locally they are known as owa jawa.

The 'Hylobates' portion of their scientific name means 'dweller in the trees.'

References

Burnie, D., 2011. Animal. 3rd ed. London: DK

Jackson, T. and Chinery, M., 2012. The illustrated encyclopedia of animals of the world. London: Southwater.

Mogo Wildlife Park - NOW OPEN 9AM-4PM DAILY. 2021. Silvery Gibbon — Mogo Wildlife Park - NOW OPEN 9AM-4PM DAILY. [online] Available at: <https://mogowildlifepark.com.au/silvery-gibbon> [Accessed 27 November 2021].

The Aspinall Foundation. 2021. Conservation of the Javan silvery gibbon. [online] Available at: <https://www.aspinallfoundation.org/the-aspinall-foundation/conservation-of-the-javan-silvery-gibbon/> [Accessed 27 November 2021].

Abrams, S., 2021. Silvery Gibbon. [online] New England Primate Conservancy. Available at: <https://www.neprimateconservancy.org/silvery-gibbon.html> [Accessed 27 November 2021].

Biomes, B., 2021. Blue Planet Biomes - Silvery Gibbon. [online] Blueplanetbiomes.org. Available at: <https://www.blueplanetbiomes.org/silvery_gibbon.php> [Accessed 27 November 2021].

Silvery.org.au. 2021. About Silvery Gibbons – The Silvery Gibbon Project. [online] Available at: <https://silvery.org.au/about/about-silverys/> [Accessed 27 November 2021].

PerthZooWebsite. 2021. Javan Gibbon. [online] Available at: <https://perthzoo.wa.gov.au/animal/javan-gibbon> [Accessed 27 November 2021].