Siamang

Hylobates syndactylus

Status in the Wild: Endangered

Range: Malaya and Sumatra, which are in southeast Asia.

Habitat: The upper canopy of the forest.

Vocalization: Siamangs have throat sac directly under their chins, which they inflate with air. This sac serves to amplify their vocal chords, similar to the hollow body of a guitar as it amplifies the sound of the strings. This sound is of incredible volume and may be heard for a good distance through the jungle if a group of siamangs is hooting in unison.

They use their high pitched sounds to establish their territory, making sure that other groups of siamangs do not trespass on their home ground. These sounds are also used for inter-group communication and for the location of a mate for breeding purposes.

At dawn and sundown, they make the forest resound with their prolonged hoots.

Primate: A siamang is not a monkey, but an ape. It is the largest of the southeast Asian gibbons and is in the same family as the chimpanzee, gorilla, and orangutan.

Description: Siamangs have no tail and have arms much longer than their legs. They hold their arms above the ground as they walk in order to balance themselves and prevent these long limbs from getting in the way. They are clumsy on the ground, but extremely graceful when moving through trees.

Transportation: Siamangs move through trees by a method called brachiation, or arm-over-arm swing. This is done by forming a hook with their elongated hands and fingers and pivoting around the branches as they swing from limb to limb. The branches are never actually gripped by the siamang. Their hands simply roll off of one branch and on to another. They have thumbs that are small and sit well back on the hand.

Gestation: The gestation period is believed to be about seven months.

Lifespan: Twenty years

Wild Status: Due to serious destruction of their rainforest habitat, all species of gibbon are on the US endangered species list.