White-handed gibbon

If an old individual of the common gibbon unable to forage for food itself lives in a group, other family members care for it and bring it food.
The family of white-handed gibbons sings a complex melody that begins with the note "mi," moves into a full octave, and then into trills.
The singing of one family of the common gibbon is joined by neighboring groups, echoing through the surroundings.
The common gibbon has white hands and feet that strongly contrast with the very dark rest of its limbs. Its face is outlined by a white stripe.
The lifespan of the common gibbon in captivity reaches 40 years.
They are true brachiators: their arms are much longer than their legs and they travel by swinging on their arms.
The white-handed (lar) gibbon gets its name from its white hands and feet.
The shoulder and wrist joints are very flexible, which aids brachiation.
Males and females perform loud duets that serve to mark territory.
The species has Endangered status, and its call can be heard up to a kilometre away.

Age

The common gibbon has a typical lifespan of from 25 to 40 years, with a maximum recorded lifespan of 56 years and a theoretical lifespan ranging from 22 years and 6 months to 55 years and 1 month. The species reaches sexual maturity between 5 and 8 years of age, and the young are born with their eyes open. During the embryonic stage, the embryo develops inside the mother, receiving nourishment from her and growing until it is ready for birth. Following birth, the infant clings to the mother’s fur, drinks milk, and gradually learns to hold onto branches for a period lasting from 1 day to 2 years. The subsequent rapid growth phase sees the young gibbon no longer drinking milk but still not fully adult, learning to find food and emit loud calls, lasting from 2 to 7 years. The adult stage begins after this, with the species living in pairs, defending their territory with loud songs, and able to reproduce for a duration of from 7 to 40 years.

Phenotype

The common gibbon has dense, dark fur as an infant and clings tightly to its mother; adult individuals possess short, dense fur and a light patch of fur on their face. The species’ forelimbs are exceptionally long and strong, enabling it to swing through branches and move rapidly through the forest. A pouch under the throat allows the animal to produce very loud, far-reaching calls.

Physiology

The common gibbon exhibits a body height ranging from 17.8 centimeters to 4.5 meters, with a body length varying from 45 to 60 centimeters and a mass between 4.65 and 6.54 kilograms; the embryo stage is characterized by a body mass of 1 to 80 grams, while the infant stage shows a body mass ranging from 300 grams to 1.8 kilograms and a body length from 15 to 30 centimeters. During the rapid growth phase, the young have a body mass between 1.8 and 4.5 kilograms and a body length from 30 to 45 centimeters; the adult stage presents a body mass of 4.8 to 7.2 kilograms and a body length from 45 to 60 centimeters.

Habitat

The common gibbon inhabits elevations up to 1.5 kilometers above sea level and lives in tropical dry forests with a hot climate and a dry season, as well as tropical moist forests that are always hot and humid. The species’ habitat includes terrestrial landscapes such as ground forests and shrubs. The climate varies; winters have little precipitation, summers have more, and the entire year can be very hot with frequent rains but occasional dryness, or consistently hot and wet with almost daily rain. The common gibbons occupy areas with little winter precipitation and summer rainfall, or environments that are always hot and humid with nearly daily rain, or places that are always very wet.

Shelter

The common gibbon inhabits the upper canopy of forests and does not have a permanent or long-term shelter; therefore, the species lacks a specific place to hide. The purpose of any temporary location is protection from predators and rest. The species does not use a fixed shelter.

Geography

The white-handed gibbon is found in the Indomalaya biogeographical region, specifically inhabiting the semi-evergreen rainforests of the Tenasserim and southern Thailand. The species occupies semi-evergreen rainforests.

Feeding

The white-handed gibbon primarily consumes ripe fruits and also eats young leaves, flowers, and occasionally insects or small vertebrates; the species obtains food by gathering it with its hands from trees. Its diet includes fruits, leaves, flowers, insects, and nectar, and the search for and acquisition of food constitutes its feeding strategy. The daily food requirement ranges from 250 grams to 450 grams. The infant lar gibbon receives nourishment from milk. The species’ prey includes net-winged insects, beetles, butterflies, flies, Hymenoptera, bedbugs, Orthoptera, dragonflies, and stoneflies.

Reproduction

The common gibbon inhabits terrestrial environments and gives birth to live young on land, not hatching from eggs or spawn. Gestation lasts 7 months and 1 week, resulting in a litter of 1 infant that the female carries with her. Common gibbons live in pairs, and the female produces one offspring, which both parents protect and raise. The species reaches sexual maturity between 5 years 6 months and 8 years. Reproduction always occurs through fertilization without generational change, exhibiting homogamy. The interval between births is from 2 to 3 years.