White-Handed Gibbon

Listed as Endangered by the IUCN Red List.

Thailand, Malay Peninsula, and Sumatra.

Tropical or lowland rain forests; almost always stays in trees.

Diurnal.

17 – 25 inches (440 – 635 mm); 8 – 18 lbs. (4 – 8 kg) for genus.

In captivity a member of one species lived for 34 years.

Mostly fruit.  Also leaves, buds and insects.

Gibbons are comparatively slim apes with extraordinarily long arms.  Their hands have short thumbs and long, curved fingers that are held together to form hooks as they swing through the canopy.  Seat pads are present, as in Old World monkeys.  Color varies from light buff to black but the hands and feet are always white.  They walk upright on the ground, arms above the head for balance.  Body is very slender.

Gestation: 7 to 7 1/2 months (200-212 days).

Offspring: Usually 1.

Parental Care: The baby clings to the female’s belly for most of the first year but the male is part of the family unit and may carry the infant part of the time as it gets older.  Weaned at about 20 months.  Offspring born every 2 to 2 1/2 years.  Sexual maturity in 8 to 9 years.

Highly territorial.  Average territory size is one hundred acres.  Their loud call is used to keep members of the family unit together and to alert other gibbons to stay out of their territory.  As many as four offspring may live in the family unit, but young begin to spend time away from the parents when about six years old.  Brachiation (swinging by the arms) is the preferred form of locomotion but they can also make impressive leaps from branch to branch.  They can make swinging leaps of almost thirty feet.  Social unit is the nuclear family (female, male and one or two offspring).

Gibbons mark their territories with songs/calls. The calls or songs consist of the adult female doing the “great call” with the adult male singing “back up”. Calls are used due to the fact that they live in very dense foliage. Many zoos participate in breeding programs such as Species Survival Plan (SSP) for this and other gibbons.