Eric Baccega / Siamang Gibbon (Hylobates syndactylus) vocalising, vocal pouch inflated, captive, native to forests of Malaysia, Sumatra and Thailand

Anup Shah / Siamang gibbon male calling, pouch inflated

Robin Chittenden / Siamang Gibbon (Symphalangus syndactylus) Thrigby Hall zoo, Norfolk, England, UK, November.

Andrew Walmsley / Male Siamang gibbon (hylobates / Symphalangus syndactylus) vocalising, with throat pouch extended, Captive, New Zealand, Endangered species

Andrew Walmsley / Male Siamang gibbon (hylobates / Symphalangus syndactylus) vocalising, with throat pouch extended, Captive, New Zealand, Endangered species

Andrew Walmsley / Pair of Siamang gibbon (Hylobates / Symphalangus syndactylus) vocalising together, note the male's extended throat pouch, Captive, New Zealand, endangered species

Eric Baccega / Two Siamang Gibbons (Hylobates / Symphalangus syndactylus) calling, vocal pouches inflated, Endangered, captive, from SE Asia

Eric Baccega / Siamang gibbons (Hylobates syndactylus) in tree, captive, IUCN red list of endangered species

Eric Baccega / Siamang gibbon (Hylobates syndactylus) hanging in tree, captive, IUCN red list of endangered species

Eric Baccega / Siamang gibbons (Hylobates syndactylus) hanging in tree, captive, IUCN red list of endangered species

ZSSD / Siamang (Hylobates syndactylus) is an arboreal, black furred gibbon native to the forests of Malaysia, Thailand, and Sumatra

Eric Baccega / Pair of Siamang gibbon (Hylobates syndactylus) vocalising, captive, native to forests of Sumatra, Malaysia and Thailand