Gibbons have a thick coat that ranges in color from black to silvery gray to ash blond. They have a slender body and no tail. The bare face is framed in white fur or other markings. The extremely long arms, with hooklike fingers, are used for brachiating (BRAKE-ee-ate-ing), or swinging from branch to branch. Scientists consider gibbons as the only true brachiators, having powerful shoulder joints for reaching overhead and a wrist that can be rotated 180 degrees for switching position without tiring the arms and upper body. Gibbons are the only apes with skin pads on their buttocks that allow them to sleep comfortably sitting up.
Gibbons are found in Southeast Asia, including China, India, Bangladesh, Myanmar, Thailand, Cambodia, Laos, Vietnam, Malaysia, and Indonesia.
Gibbons prefer the upper forest canopy, where fruits are abundant and spreading branches allow for continuous travel. They also thrive in surviving areas of forests that have been logged.
Ripe fruits are gibbons’ main diet. Figs are their favorite. They also feed on leaves, flowers, buds, shoots, bird eggs, young birds, and insects.
BEHAVIOR AND REPRODUCTION
Gibbons are predominantly arboreal (treedwelling), defending their territory by chasing intruders and shaking branches. They sing to advertise ownership. Gibbons brachiate by grasping one branch after another or by propelling themselves through the air, loosening their grasp. They walk upright on wide branches or on the ground, arms held overhead to avoid tripping. They are diurnal (active during the day), but go to sleep before dark, sleeping in a sitting position.
The family consists of the parents and one to four juveniles. Females have single births every two or three years. The mother carries the infant around her waist for the first two months. When a juvenile reaches the age of five, the parent of the same sex may start chasing it off. Offspring who refuse to leave home stay in the vicinity of the family, but keep a distance when feeding and sleeping. Most leave home when they become sexually mature, or able to reproduce, at age seven or eight.
GIBBONS AND PEOPLE
Gibbons are popular zoo animals. The Ibans, the native people of Borneo, believe gibbons are human reincarnation, or the reappearance of a loved one’s soul in the animal’s body. Infants are captured for the pet trade.
The IUCN lists the Moloch gibbon and the eastern black gibbon as Critically Endangered, facing an extremely high risk of extinction in the wild, due to hunting, as well as habitat loss and degradation from logging and human settlement. The hoolock gibbon and the black crested gibbon are listed as Endangered, facing a very high risk of extinction, due to habitat loss and degradation from human activities. The pileated gibbon, the Kloss gibbon, and the golden-cheeked gibbon are classified as Vulnerable, facing a high risk of extinction, due to habitat loss and degradation from human activities.