Swing into World Gibbon Day with an animal that knows a thing or two about swinging: siamangs! With hook-like hands for grasping branches, long arms for reaching and specialized shoulder joints for brachiating — there’s no doubt these apes have some amazing adaptations! Learn more about siamangs in this Q+A with primate keeper Carly Hornberger.
Where in the world do siamangs live?
Siamangs are native to Sumatra, Malaysia, and a small area of Thailand. They are found in rainforests, monsoon forests, and in mountains.
What special adaptations do they have?
Siamangs have long arms, slender bodies, and lightweight bones all of which help them navigate the treetops by brachiating. When moving slowly, they swing much like a pendulum as they grab one branch and release it before grabbing the next, so that the body is freely projected through the air. Flights of 25 to 32 feet (8 to 10 meters) have been witnessed.
In addition to long arms, siamang thumbs have evolved to be shorter and lower on their hands so it doesn’t get in the way while brachiating – this adaptation is also seen in other gibbon species and orangutans.
How do the Zoo’s siamangs use their natural behaviors?
Keepers hang enrichment up high to encourage our siamangs to stay up off the ground. Our exhibits are extremely tall and allow our siamangs to relax up high like they would in the wild. Keepers also give our siamangs lots of enrichment to keep their minds sharp and encourage foraging behaviors.
What role do siamangs play in their native habitat?
Siamangs’ main role in the wild is seed dispersal. When they ingest fruit, they also consume the seeds. Siamangs pass the seeds in their feces throughout their territory. This creates a healthier and diverse tree population.
How do gibbons spend their day in the wild?
Siamangs are diurnal – meaning they wake up at dawn and go to bed in the early evening. First thing in the morning, most gibbon species will break out into song – these songs announce their presence within the treetops and claim their territory.
These songs also act as a bonding tool between paired siamangs. Most of their day is spent foraging for food with an equal amount spent resting. When not foraging or resting, siamangs are either traveling or grooming.
How do they spend their day at the Zoo?
Our siamangs—Adi, Guntur, Bradley and Ronnie—spend most of their day working on enrichment! After morning wellness checks and enclosure cleaning, we spread their diet out throughout the day in various types of enrichment. We keep a monthly enrichment calendar to make sure we spread items out and keep variety in their day.
Keepers also make time for positive reinforcement training with all our siamangs, which allows our siamangs to voluntarily participate in their own healthcare.
You can follow a day in the life of our siamangs, Adi and Guntur, in this blog! And, get to know our older siamangs, Bradley and Ronnie, in this update.
What do siamangs eat?
In the wild, siamangs mainly eat fruit and leaves. They will occasionally eat eggs, insects, or small vertebrates.
Here at the zoo, they are fed a mixture of kale, romaine lettuce, carrots, beets, celery, sweet potato, apples, bananas, oranges, and primate chow multiple times a day. Amounts depend on the make-up and ages of each group. Each animal receives a hardboiled egg once a week. Special novel items are saved for training – like pasta!
What do you enjoy most about working with siamangs?
Siamangs (and other gibbons) are the only primates considered small apes, which make them super unique! I love their daily songs and think our four siamangs have fun, huge personalities in small bodies. They are super smart and learn new behaviors and how to conquer new enrichment items quickly.
I hope visitors fall in love with siamangs, just like I have. I also hope they take away the urgency in protecting their habitats from deforestation and protecting siamangs from the pet trade.
What threats do siamangs face in the wild?
Siamangs are considered endangered by the International Union for Conservation of Nature. Unfortunately, their numbers are in decline mainly due to habitat loss and the illegal pet trade.
The largest reason for their habitat loss is the palm oil trade. Over 85% of the world’s palm oil is produced in Indonesia and Malaysia. Siamang habitats are burnt down to make way for palm tree plantations. Adult siamangs are killed so their young can be sold into the illegal pet trade, even with laws in place protecting siamangs.
The Association of Zoos and Aquariums' Ape Taxon Advisory Group (AZA Ape TAG) has supported conservation initiatives such as anti-poaching patrols and law enforcement, additional research and support from zoos, improved management of protected areas and support of sanctuaries, and increased community involvement to help protect apes.
I want to help siamangs in the wild and at the Zoo! What can I do?
Reduce, reuse, and recycle! Recycling is one of the best ways to help many endangered species. Cut back on single-use goods, find creative ways to use products at the end of their life cycle, and recycle paper, glass, plastic, and electronics whenever possible.
Try to purchase items with sustainable palm oil. Research shows that when palm oil is produced sustainably, with zero deforestation, the plantations can be a positive element in the local agroecological system, even attracting wildlife.
Planning a vacation? Then this tip is for you! Practice ecotourism and refrain from purchasing products made with or from animal parts. Avoid taking photos with primates.
The IUCN recently published guidelines for interacting with primates stating, “Images of primates with people in popular media decrease appropriate public perceptions of primates, increase the potential for cross–cultural misunderstandings, increase inappropriate interactions with primates that can decrease welfare and rehabilitation efforts, and decreases primate conservation efforts in all contexts. The negative effects of publishing such images may therefore outweigh the positive effects, and we must apply the precautionary principle, given the extent of the extinction crisis.”
Last, share some of the fun facts you’ve learned here about gibbons with others. Simply raising awareness about these animals can encourage others to appreciate and want to conserve them, too.
Swing into the Smithsonian’s National Zoo and Conservation Biology Institute and visit siamangs Bradley, Ronnie, Adi and Guntur at Gibbon Ridge! Want to learn more fun facts about gibbons? Check out How Long Are A Gibbon’s Arms? And More Gibbon Facts.