10 Amazing Facts About Orangutans

The term orangutan is derived from a Malay dialect, meaning 'man of the forest.' These distinctive apes, with their reddish-brown fur, stand out in many ways, from their biology to their social behavior. Here are 12 fascinating facts about these extraordinary primates.

1. Orangutans are indigenous to Southeast Asia.

Orangutans inhabit the rainforests of Sumatra and Borneo and are the only great apes native to Asia, apart from Homo sapiens. There are three recognized species of orangutans: the Sumatran (Pongo abelii), Bornean (Pongo pygmaeus), and Tapanuli (Pongo tapanuliensis). The Tapanuli species was officially identified as distinct only in 2017.

2. Orangutans are the largest mammals that live in trees.

Orangutans are primarily tree-dwellers, spending around 95 percent of their lives in the canopy. They eat, drink, rest, and sleep in the trees. Like other great apes, they construct a new nest from branches and twigs every night to sleep in, keeping them safe from predators. They also make their nests cozy by adding a layer of leaves or placing a large frond overhead to shield them from rain.

3. Female orangutans give birth approximately once every eight years.

Orangutans have the longest birth interval of any terrestrial mammal. Their infants nurse for as long as eight years, the longest duration among mammals. They reach their adolescent years before becoming independent and attaining sexual maturity. In the wild, orangutans live for 40 to 50 years, and in captivity, they can live up to 60 years [PDF].

4. An orangutan’s arms are longer than its legs.

Orangutans are perfectly adapted for life among the treetops. Large males can have an arm span exceeding six feet, which is longer than Tom Hanks' height. Their long upper limbs allow them to swing effortlessly between branches, grasping them with both their hands and feet, a technique known as quadrumanous scrambling.

5. Orangutans exhibit significant sexual dimorphism.

Similar to many other species (including humans), male and female orangutans display distinct physical differences. Adult male orangutans typically stand about 4.5 feet tall and weigh between 130 and 200 pounds, while adult females are around 4 feet tall and weigh approximately 90 to 110 pounds [PDF]. Mature males grow prominent, flat cheek pads called flanges and possess larger throat sacs than females. These sacs amplify their deep 'long calls' to attract females, which can be heard over a distance of more than a mile. While both males and females can grow beards, males typically have more pronounced facial hair, which can also include mustaches.

6. Orangutans consume a lot of fruit.

These apes build up their body mass primarily on a fruit-based diet, although they also consume nuts, leaves, bark, and occasionally insects or a bird egg. According to the San Diego Zoo, orangutans are known to eat over 500 different types of fruit, with figs and durians being among their favorites. Other commonly consumed fruits include lychees, mangoes, and mangosteens.

7. Orangutans and humans share 97 percent of their DNA.

This makes orangutans, which diverged from the human lineage approximately 13 million years ago, our most distant relatives among the great apes. Our closest living relatives, chimpanzees and bonobos, share 98.7 percent of their DNA with us (and 99.6 percent with each other). Gorillas and humans share 98 percent of their DNA.

8. Orangutans are exceptionally intelligent.

Orangutans use tools to search for food in the wild and can observe and mimic human actions, such as operating hammers and saws, washing clothes, and even rowing a canoe. They can also master human-made technology. In the 1960s, a captive orangutan named Fu Manchu repeatedly escaped from his enclosure at the Omaha Zoo in Nebraska after learning to pick the lock with a piece of wire.

9. An orangutan was legally recognized as a 'non-human person.'

In 2014, lawyers in Buenos Aires, Argentina, argued that an orangutan named Sandra, held at a local zoo, was being unlawfully confined and mistreated. A judge ruled that Sandra was entitled to the basic rights of personhood, including the right to live free from physical or psychological harm, and should no longer be confined at the zoo. Sandra eventually moved to a great ape sanctuary in Florida.

10. All three orangutan species are critically endangered.

The primary threats to orangutans are habitat destruction due to logging, both legal and illegal, as well as deforestation for palm oil plantations, and land clearing for timber, mining, housing, and tourism. Fires, often uncontrollable, frequently destroy trees and leave orangutans orphaned or dead. Efforts to conserve orangutans include national and international protection laws, strengthening enforcement of these laws, preserving forests, and reintroducing captive-bred orangutans back into the wild.