What is the largest primate in the rainforests of Southeast Asia?

The orangutan is the largest primate living in the rainforests of Southeast Asia. Orangutans are great apes in the genus Pongo, native today to the Indonesian islands of Sumatra and Borneo, with the Tapanuli orangutan restricted to northern Sumatra.

They are the most arboreal of the great apes, spending much of their lives in the forest canopy. Their long arms, powerful hands, and flexible joints help them move between trees, while their broad diet includes fruit, leaves, bark, insects, and occasionally small animals. Adult males are substantially larger than females and may develop prominent cheek pads called flanges.

“Largest primate” here means the largest living primate native to that region, not the largest primate on every continent. Gorillas are heavier, but they live in Africa; chimpanzees also live in Africa, and gibbons are much smaller. Orangutans are also the largest predominantly tree-dwelling apes.

Modern orangutans represent three recognized species: the Bornean, Sumatran, and Tapanuli orangutans. All are critically endangered, threatened by habitat loss, logging, fires, hunting, and the conversion of rainforest to agriculture.