Abbott’s Gray Gibbon, Bangka Slow Loris, Black-crested Sumatran Langur, Bornean White-bearded Gibbon, Proboscis Monkey, Silvered Langur, and Western Tarsier are a few of the monkey species endemic to Borneo island.

Proboscis monkeys are endemic to the jungles of Borneo, never straying far from the island’s rivers, coastal mangroves, and swamps. They are a highly arboreal species and will venture onto land only occasionally to search for food. They live in organized harem groups consisting of a dominant male and two to seven females and their offspring.

Orangutans share Borneo's forests with 12 other primate species, including 2 gibbon species, 5 langurs, 2 macaques, the tarsier (Tarsiusbancanus), the slow loris (Nycticebuscoucang), and the endangered proboscis monkey (Nasalislarvatus).