Photo of the Month: Siamang

By Megan Runquist Holmstedt

Siamang; PHOTO CREDIT: Jamie Pham

Status: The siamang (Hylobates syndactylus) is listed as Endangered by the International Union for Conservation of Nature (IUCN). The species’s population has declined at least 50% in the past 40 years, primarily due to collection for the pet trade and dramatic habitat loss caused by logging and agriculture.

Habitat: This primate is found in the tropical rainforests of Sumatra, Malaysia, and a small area of Thailand’s southern peninsula.

Diet: A typical siamang diet consists of leaves, fruit, some insects, and the occasional small vertebrate. About half of the diet is purely leaves, making the species much more folivorous than other apes. Since they are also frugivorous, siamangs disperse seeds through their feces, which helps support forest regeneration.

Members of this family (Hylobatidae) are known as gibbons; they are the smallest of the world’s apes. Siamangs are the largest species of the category, weighing 20-28 pounds, with shaggy hair and no tail. They have the largest arm-to-leg ratio of any primate (their arms are nearly 1.5 times the length of their short legs), which helps them swing effortlessly through the trees–a mode of transportation called brachiation.

Siamangs are easily distinguishable by their large throat sacs, which can inflate to a size comparable to the siamang’s entire head. They use these sacs to produce a loud, booming call in order to establish or defend territory from other siamangs as well as to reinforce their pair bond. These apes are typically monogamous, and the L.A. Zoo’s siamangs usually start their morning duet around 11 a.m.

In January 2017, a male siamang was born at the Zoo to mother Charlotte and father Sam. The family’s exhibit is at the top of the Zoo, across from the Sichuan takin.