Habitat

Silvery Gibbons inhabit the isolated pockets of primary rainforests on the western side of Java.

Natural behavior

Silvery Gibbons live in monogamous family groups consisting of the parents and up to 4 immature offspring. They are strictly arboreal and rarely descend to the forest floor. Adaptions to their wrists and shoulders support them when brachiating through the forest canopy. The female’s loud call and song early in the morning acts to defend their territory.

Description

Body hair is grey all over with a dark hairless face with light grey eyebrows. Arms and fingers are long with reduced thumbs.

Distribution

Fragmented populations in the western half of Java

Diet

Mainly frugivorous, they also eat leaves, flowers, nuts and insects.

Reproduction

A single offspring is born after a gestation period of 210 days. Birth interval is 2-3 years. Sexual maturity is reached between 5-7years. Average lifespan in the wild is 35 years. Gibbons in captivity can live up to 50 years.

Social structure

Social, living in family units of up to 6 individuals. Groups consist of a dominant male and female breeding pair and their immature offspring.

Threats

The biggest threat to the survival of Silvery Gibbons is habitat loss and human encroachment. Less than 4% of their original habitat exists and is still on the decline. The illegal pet trade and poaching is another ongoing threat.