Species Fact Profile: Siamang (Symphalangus syndactylus)

Siamang

Symphalangus syndactylus (Raffles, 1821)

Range: Southeast Asia, Sumatra
Habitat: Tropical Rainforest
Diet: Fruits, Leaves, Insects, Flowers
Social Grouping: Territorial Pairs or Family Groups
Reproduction: Monogamous, single offspring born every 2-3 years.  Gestation period of 230 days; infant initially clings to mother, at about one year of age spends more time on the father.  Infant may nurse for as long as 24 months. Young siamangs become independent at 6 years of ago, sexually mature at 8-9 years
Lifespan: 35 Years
Conservation Status: IUCN Endangered, CITES Appendix I

• Largest of the gibbon species, standing up to 1 meter tall and weighing up to 14 kilograms; individuals from Sumatra are slightly larger than those from Malaysia
• Both sexes look alike, with shaggy black fur and a gray area around the mouth and chin (infants are entirely black)
• Differ from other gibbons in the partially "webbed" fingers (Latin name Symphalangus translates to "together fingers") and the throat sac on males and females
• Calls (amplified by their throat pouches) can be heard from 2 kilometers away and are used to maintain pair bonds and to establish territories.  Calls may go on for 15 minutes at a time
• Walk on hind legs when on the ground, but spend most of their time in trees, where they move through brachiating (swinging with their arms from one branch to another), sometimes clearing 10 meters with one swing.  Siamangs are slower and more sedentary than other gibbons.
• Populations on Sumatra and mainland Southeast Asia are sometimes considered separate subspecies
• Main threats are loss of habitat and forest fragmentation, as well as capture for the pet trade