(Symphalangus syndactylus)

Habitat and Distribution: Found in treetops of tropical rain forests and monsoon forests on the island of Sumatra and the Malay Peninsula.

Size: 30-35 inches tall; 17-35 pounds

Wild Diet:
Leaves, fruit, flowers, bird eggs, and insects

Humans and leopards

Reproduction: Siamangs are ready to mate between 5-7 years of age. Females give birth to a single offspring every 2-3 years after a gestation period of about 7 months. The infant clings to its mother’s belly for the first 3-4 months. The father takes over the daily care of the baby when it is about one year old.

Behavior: Siamangs are monogamous and highly territorial, living in family units consisting of one mated pair and up to four offspring. Family units are active during the day, waking at sunrise and setting out in search of food for about 8-10 hours before returning to their sleeping place. Unlike the great apes (e.g. chimpanzees, gorillas, and orangutans), which build sleeping nests or platforms, siamangs sleep sitting upright high in the trees, with arms folded and head between their knees.


IUCN Status: Endangered

Siamangs are at risk due to habitat destruction for logging and agriculture. Currently, less than 5 percent of their remaining habitat is protected.

The siamang has a Species Survival Plan (SSP).

Did you know?

  • Siamangs’ arms are longer than their legs, spanning up to five feet in a large adult.
  • Mated pairs use vocalizations to bond and to defend their territory. Each pair creates a unique duet that includes booms, barks and hoots.