Silvery Gibbon

Silvery Gibbon

Moloch, Javan gibbon

Kingdom
Phylum
Subphylum
Class
Order
Suborder
Infraorder
Family
Genus
SPECIES
Hylobates moloch
Population size
below 2,500
Life Span
30-40 yrs
TOP SPEED
56 km/h
WEIGHT
6 kg
LENGTH
45-64 cm

Silvery gibbons are some of the ‘lesser apes’, which differ from great apes (gorillas, chimpanzees, orangutans and humans) by being pair-bonded and smaller, in not building nests, and in some anatomical features where superficially they are closer in appearance to monkeys than great apes. These gibbons have sliver-gray fur which is long and fluffy, and have darker markings on the cap and chest. They have long legs and long arms that have long fingers with reduced thumbs, which are all adaptations for swinging from branch to branch, arm over arm).

Distibution

The Silvery gibbon is native to the western part of Java, Indonesia. It occurs in the upper canopy of the hill and lowland forests. They spend most of their time up in trees, rarely descending to the forest floor.

Silvery Gibbon habitat map

Geography

Continents
Subcontinents
Countries

Climate zones

Habits and Lifestyle

Groups of Silvery gibbons usually consist of a mated pair, their infant and a juvenile, the average group size being four individuals. They are diurnal animals, and are highly territorial, defending their territories with "singing." Each morning, the female will announce to the forest her presence by calling and shrieking, often being heard as far as a kilometer away. Silvery gibbons swing from branch to branch to move around the forest. They can walk on the ground when necessary, walking on two legs with their arms held above their heads for balance.

Lifestyle

Diet and Nutrition

Silvery gibbons are frugivorous, and eat ripe fruits from the upper canopy of tropical rainforests. They also eat leaves and flowers.

Mating Habits

MATING BEHAVIOR
REPRODUCTION SEASON
Year-round
PREGNANCY DURATION
7-8 months
BABY CARRYING
1 infant
INDEPENDENT AGE
8 years
FEMALE NAME
female
MALE NAME
male
BABY NAME
infant

Silvery gibbons are monogamous, mating for life. Breeding occurs at any time during the year. Females produce one baby every 2 to 3 years or so. Gestation lasts 7 to 8 months. The mother keeps her baby close to her for warmth and nurses it for about a year. Offspring live with their family group until they are fully mature at around 8 years old, when they are ready to go and find a mate. Families are usually very tightly bonded and stay close to each other when traveling.

Population

Population threats

The Silvery gibbon is threatened with extinction as a result of forest degradation, the clearing of land for agricultural purposes and the illegal wildlife trade. Infants are taken from their mothers to be sold in the illegal market, the mother often being killed in the process.

Population number

According to the IUCN Red List, the total number of Silvery gibbons is fewer than 2,500 mature individuals. Their population numbers are decreasing today, being classified as endangered (EN) on the list of threatened species.

Fun Facts for Kids

  • A male Silvery gibbon makes a simple ‘hoot’ when it calls, whilst the call of a female is more variable. If threatened while in their territories, the female sings and screams while the male pursues the intruder, usually making a lot of noise while crashing through branches.
  • Unlike other gibbons, Silvery gibbons do not sing ‘duets’. Female are the dominant vocalists, while males sing only occasionally.
  • Silvery gibbons keep away from water because they are not swimmers.
  • Silvery gibbons sleep in trees, in an upright position. Instead of building nests they bed down in forked branches.
  • Gibbons are highly intelligent. They are able to recognize themselves in a mirror.
  • Silvery gibbons spend 36% of their time feeding, 41% in resting, 6% participating in social behavior, 15% traveling, and 2% in aggressive behavior.
  • Gibbons have the longest arms relative to their body size of any of the primates. Their arms being longer than their legs helps them to swing from one tree to another.

References

1. Silvery Gibbon Wikipedia article - https://en.wikipedia.org/wiki/Silvery_gibbon
2. Silvery Gibbon on The IUCN Red List site - http://www.iucnredlist.org/details/10550/0

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