Siamang

Siamang

Symphalangus syndactylus

Silhouette: Kai R. Caspar · PhyloPic

LCNTVUENEndangeredCR
Daily sighting probability ~30% · Possible
at Gunung Leuser National Park

In 3 days ~70% in a week ~90%

34 Verified sightings at Gunung Leuser National Park From 2019 to 2026
77 In all 3 parks
January Best month
🌅 Crepuscular When it's spotted

About the Siamang

The siamang (also UK:; Symphalangus syndactylus) is an endangered arboreal, black-furred gibbon native to the tropical rainforests of Indonesia, Malaysia, and Thailand. The largest of the gibbons, the siamang can be twice the size of other gibbons, reaching 1 m (3.3 ft) in height, and weighing up to 14 kg (31 lb). It is the only species in the genus Symphalangus. Fossils of siamangs date back to the Middle Pleistocene.

Two features distinguish the siamang from other gibbons. First, two digits on each foot—the second and third toes—are partially joined by a membrane, hence the specific name syndactylus, from the Ancient Greek σύν, sun-, "with" + δάκτυλος, daktulos, "finger". Second, a large gular sac (throat pouch), found in both males and females of the species, can be inflated to the size of the siamang's head, allowing it to make resonating calls.

Otherwise, the Malaysian individuals are only a population. The siamang occurs sympatrically with other gibbons; its two ranges are entirely within the combined ranges of the agile gibbon and the lar gibbon. The siamang can live to around 40 years in captivity. While the illegal pet trade takes a toll on wild populations, the principal threat to the siamang is habitat loss in both Indonesia and Malaysia. The palm oil production industry is clearing large swaths of forest, reducing the habitat of the siamang, along with those of other species, such as the Sumatran tiger. Wikipedia →

Sounds

Song1:22

Indonesia · 2016

© Frank Lambert · XC1031364 · CC BY-NC-ND 4.0

Song0:55

Malaysia · 2012

© Marc Anderson · XC960738 · CC BY-NC-ND 4.0

Recording0:28

Malaysia · 2011

© dbeadle · iNaturalist · CC BY-NC 4.0

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Kerinci Seblat National Park 🇮🇩 Indonesia
~50%
2 Way Kambas National Park 🇮🇩 Indonesia
~50%
3 Gunung Leuser National Park 🇮🇩 Indonesia
~30%

Zoos & Centres Where Found

# Zoo / Centre Country
1 Disney's Animal Kingdom 🇺🇸 United States In captivity
2 Ragunan Zoo 🇮🇩 Indonesia In captivity
3 Busch Gardens Tampa 🇺🇸 United States In captivity
4 San Diego Zoo 🇺🇸 United States In captivity
5 Pairi Daiza 🇧🇪 Belgium In captivity
6 National Zoological Park 🇺🇸 United States In captivity
7 Denver Zoo 🇺🇸 United States In captivity
8 Dublin Zoo 🇮🇪 Ireland In captivity
9 Lisbon Oceanarium 🇵🇹 Portugal In captivity
10 Tulsa Zoo 🇺🇸 United States In captivity
11 Fota Wildlife Park 🇮🇪 Ireland In captivity
12 Zoologic park de Lille 🇫🇷 France In captivity
13 Taronga Western Plains Zoo 🇦🇺 Australia In captivity
14 Nandankanan Zoological Park 🇮🇳 India In captivity
15 Zoo Miami 🇺🇸 United States In captivity
16 Taipei Zoo 🇹🇼 Taiwan In captivity
17 Columbus Zoo and Aquarium 🇺🇸 United States In captivity
18 Khao Kheow Open Zoo 🇹🇭 Thailand In captivity
19 Baton Rouge Zoo 🇺🇸 United States In captivity
20 Nashville Zoo at Grassmere 🇺🇸 United States In captivity
21 Omaha’s Henry Doorly Zoo and Aquarium 🇺🇸 United States In captivity
22 Milwaukee County Zoo 🇺🇸 United States In captivity
23 Orana Wildlife Park 🇳🇿 New Zealand In captivity
24 Oakland Zoo 🇺🇸 United States In captivity
25 Phoenix Zoo 🇺🇸 United States In captivity
26 Jacksonville Zoo and Gardens 🇺🇸 United States In captivity
27 Cape May County Park & Zoo 🇺🇸 United States In captivity
28 Leofoo Village Theme Park 🇹🇼 Taiwan In captivity
29 Louisville Zoo 🇺🇸 United States In captivity
30 Audubon Zoo 🇺🇸 United States In captivity
31 Dakota Zoo 🇺🇸 United States In captivity
32 Zoológico de San Juan de Aragón 🇲🇽 Mexico In captivity
33 Safari Niagara 🇨🇦 Canada In captivity
34 Woodland Park Zoo 🇺🇸 United States In captivity
35 Edinburgh Zoo 🇬🇧 United Kingdom In captivity
36 Zoológico de Goiânia 🇧🇷 Brazil In captivity
37 Chiba Zoological Park 🇯🇵 Japan In captivity
38 National Zoo of Malaysia 🇲🇾 Malaysia In captivity
39 ZooTampa 🇺🇸 United States In captivity
40 Dickerson Park Zoo 🇺🇸 United States In captivity
41 Gatorland 🇺🇸 United States In captivity
42 Lisbon Zoo 🇵🇹 Portugal In captivity
43 Metro Richmond Zoo 🇺🇸 United States In captivity
44 Montgomery Zoo 🇺🇸 United States In captivity
45 Virginia Zoological Park 🇺🇸 United States In captivity
46 Zoo de La Flèche 🇫🇷 France In captivity
47 Cleland Wildlife Park 🇦🇺 Australia In captivity
48 DierenPark Amersfoort 🇳🇱 Netherlands In captivity
49 Houston Zoo 🇺🇸 United States In captivity
50 Zoo Opole 🇵🇱 Poland In captivity

Before you go

What are the chances of seeing a Siamang in Gunung Leuser National Park?

Possible

About 30% of wildlife watchers report a Siamang sighting in Gunung Leuser National Park on a given day, based on 34 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 7th most-seen of the 19 mammals we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.

When is the best time to see a Siamang in Gunung Leuser National Park?

January and September

In those months about 40% of wildlife watchers report a Siamang in Gunung Leuser National Park on a given day, against under 5% in August, the lowest month.

What time of day is best to see a Siamang?

Between 2 and 5 am

Across all the parks we cover, that three-hour window holds the most Siamang sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is most active around dawn and dusk.

Is Gunung Leuser National Park the best place to see a Siamang?

3rd of 3

Of the 3 parks where we can rate Siamang sightings, Gunung Leuser National Park ranks 3rd at about 30%. The best odds are in Kerinci Seblat National Park (Indonesia, about 50%) and Way Kambas National Park (Indonesia, about 50%).

Where does the Siamang sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Siamang is recorded against all the mammals logged in Gunung Leuser National Park (34 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.

← Back to Gunung Leuser National Park