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All Creatures,

Episode 113: Gibbons, Their Songs are Fading Fast

September 03, 2019

Not many are aware that Gibbons are a lesser ape, and one of our closest relatives’ outsides the great apes. These awe-inspiring primates live-in Southeast Asia and every single species is now under threat of extinction. Not only do they have some radical physiology, their behavior, especially the singing of their songs, will win your heart. In this episode we talk about the critically endangered Northern White Cheeked Gibbon, and cover much about their other gibbon relatives.

Gibbon History

The Gibbon family is quite unique of many animals we have covered to date. First, they are classified as a “lesser ape” and they differ from the much larger great apes. The great apes consists of humans, chimpanzee, bonobo, orangutan, and gorilla.  The lesser apes are the gibbons and siamangs. All differ from monkeys, in that they do not have a tail, have flatter noses, and tend to have more advanced animal behaviors.

What makes Gibbons so unique is that while they belong to the Hylobatidae family, they spread out into four separate genera. Each genus has their own total chromosome count. Overall, there is believed to be 20 sperate species of gibbons spread out among these four genera.

The four genera are:

  • Hylobates (9 species) with 44 chromosomes
  • Hoolock (3 species) with 38 chromosomes
  • Nomascus (7 species) with 52 chromosomes
  • Symphalangus (1 species: Siamang) with 50 chromosomes

The Northern White Cheeked Gibbon belongs to the Genus Nomascus and has the scientific name of Nomascus leucogenys.

Gibbons evolved from a common ancestor with the orangutan nearly 20 million years ago. A primate ancestor migrated to Asia millions of years ago and this diverged into the gibbons and orangs.

Gibbon Physiology

Some of the most endearing information to come from this episode is not only the Gibbon song, which is critical in forming and maintaining social bonds, but also their family group dynamics. Typically, gibbons are monogamous, though they are known to stray and may even “divorce.” They have complex social structures, living in family groups, and are both excellent parents and care takers.

Gibbons are also one of the world’s most impressive brachiators. Meaning, they live high in the tropical rain forest canopy and swing from branch to branch. It has been recorded that gibbons can reach speeds of up to 35 mph (55 kph) while swinging through the treetops. They also have been seen to leap as far as 25 feet (8 m) between branches. Their forelimbs are specially built, allowing them great flexibility when hanging from a tree, but also have powerful shoulders and other special adaptations that allow them to fly in the trees with ease.

Gibbon diets are primarily fruits and other seeds. This makes them a critical piece in the food web of any tropical rain forest. Their ability to spread seeds through their feces helps maintain a healthy population of trees and other plants in this incredibly diverse ecosystem. So many species also depend on the gibbon and the maintenance of healthy biome in this region of the world.

Gibbon Conservation

The plain and ugly news is, every species of gibbon is now under the threat of extinction. The rapid deforestation happening in Southeast Asia, mainly for the development of palm oil plantations has pushed many of these animals to the brink.

The Northern White Cheeked Gibbon is listed as critically endangered, with a population of less than 1000 animals left in the world.

Other endangered gibbons include the:

The story is every similar for the remaining 15 species, all are in trouble and heading towards extinction.

YOU can help. We have to be aware of the products we purchase and where they source their palm oil. Please consider downloading the Cheyenne Mountain Zoo Palm Oil app HERE

Organizations to Support

Gibbon Conservation Center

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