By Diane Shea & Tammy Buhrmester
Have you ever been to the Wortham World of Primates at the Houston Zoo and heard singing but did not know where it was coming from? Once you find them, do you know what animal they are and why they are singing that song?
Gibbons are full of mysteries!
Gibbons are primates; apes more specifically. Most people are familiar with the great apes (gorilla, chimpanzee, orangutans, and bonobos), however, there are also lesser apes (meaning smaller in size). Gibbons are lesser apes.
Gibbons are small-bodied (about 12-20 pounds) and fast. Gibbons are masters of their primary mode of locomotion called brachiation, or swinging from branch to branch using their arms. They can travel through the canopy of the forest up to 35 miles per hour. You will find gibbons at home in the treetops, seldom coming to the ground. When they are on the ground they will walk bipedally with their arms raised up for balance. They are the fastest and most agile of all tree-dwelling, nonflying mammals. Since they are so high in the trees and travel so quickly, it is very difficult to see them in their native habitat of Asia.
Gibbons are social animals; they are strongly territorial and defend their boundaries with vigorous visual and vocal displays. There are few sounds in nature more evocative than the whooping song of a gibbon. The sound can be heard for a distance of up to half a mile consisting of a duet between a mated pair. Yet the songs, performed by both sexes, are highly complex and their subtleties and nuances are far from fully understood. Males accompany females and create complex duets and the degree of synchronization between the sexes increases with practice, and the quality of the song relates to the length of time they have been together. Each species of gibbon has its own song, and each male and female song differs from one another.
The Houston Zoo is home to a pair of siamang gibbons who have been living together for a couple of years. You will most likely hear their duet early in the morning before they go outside, or later in the afternoon. Male and female siamangs are normally similar in size, but Jambi, our 19 year old female, is quite a bit larger than our 15 year old male, Berani. You will find the pair relaxing together, or grooming each other, and occasionally engaging in play behavior. Jambi is particularly fond of twirling around and around on a large sheet tied to a rope in the exhibit, and Berani will hang from a rope above Jambi and tap her gently to get her to play with him.
The song of the siamangs is often enhanced by the voice of our agile gibbon, Susie. She will frequently start her own song early in the morning and the siamangs will begin theirs in response. Susie is an extraordinary 43 years old, and is one of the Zoo’s longest residents. Despite her advanced age, she is still a feisty lady and makes her preferences for certain foods known by open-mouth threatening keepers if they make the mistake of offering her the least favorite items in her diet first.
Susie is a special, but all too common, case. In her earliest years she was taken from her mother and kept as a pet by a private individual. By the age of three she had grown too dangerous to handle and was donated to the Zoo. Having missed the chance for proper socialization with her own kind, she cannot be placed with another gibbon. Because of this she gets extra attention from her keepers each day. Although Susie was born in captivity, many gibbons continue to be taken from the wild for the pet trade, often with far less pleasant results.
In addition to the pet trade, gibbons are threatened by habitat destruction. One of the main causes of deforestation is the palm oil industry. Palm oil is in many of the common substances and foods that we use. By purchasing products that use certified sustainable palm oil, we can ensure that we are supporting companies that are committed to helping gibbons.
The plight of the gibbon is often overshadowed by their larger ape cousins, but they are considered the most threatened primate; a gibbon will likely be the first ape extinction our generation will witness.
On Saturday, November 28 and Sunday, November 29, the Houston Zoo primate department will be celebrating the Year of the Gibbon, with an event called “Thanksgibbon”. We would like to invite you to come to the zoo and meet these wonderful apes, learn about them, perhaps hear them sing, and help us raise money to support this beautiful species by purchasing palm oil free body products, paintings done by Houston Zoo primates, and assorted conservation products.
Once you have given thanks for your friends and family, filled your belly with Thanksgiving food, taken that after meal nap, and done your Black Friday shopping, please join us to help! And, give Thanks that we have gibbons!