A unique primate found only on Siberut Island, the largest of the Mentawai Islands off the western coast of Sumatra, Indonesia. Because Siberut has been isolated from the mainland for thousands of years, its wildlife has evolved along a separate path, and the Siberut macaque reflects this long history of island life. Medium-sized and sturdy, this macaque has thick fur that ranges from grayish-brown to darker tones, well-suited for the humid tropical forests it inhabits. Its face is expressive, with keen eyes that show intelligence and constant awareness of its surroundings.

This macaque lives mainly in dense tropical rainforests, including both primary and secondary forests. It is active during the day and spends its time moving between the forest canopy and the ground. In the trees, it finds safety, resting spots, and fruit, while the forest floor provides fallen food and additional resources. The Siberut macaque is an agile climber but also comfortable walking and foraging on the ground, showing flexibility that helps it survive in a changing environment.

Social life is central to the Siberut macaque’s behavior. These macaques live in groups made up of multiple males, females, and young individuals. Group living provides protection from predators and allows individuals to share information about food sources. Communication within the group is rich and varied, involving vocal calls, facial expressions, body postures, and frequent grooming. Grooming is especially important, helping strengthen social bonds, reduce stress, and maintain harmony within the group. Young macaques spend much of their time playing, chasing, and climbing, which helps them develop physical strength and learn social rules.

The diet of the Siberut macaque is varied and changes with the seasons. Fruits make up a large part of its diet, but it also eats leaves, seeds, flowers, and insects. This flexible feeding strategy allows it to cope with fluctuations in food availability.

Distribution

Country

Population est.

Status

Year

Comments

Indonesia

17,000-30,000

Official estimate

EN

2015

Sumatera