Orangutans (Pongo) are the largest arboreal mammals. They are adapted for life in the trees and have longer arms than legs. They also have feet and hands that are made for grasping and unique fingerprints. Orangutans are covered in red hair. Males are larger than females and have different throat and cheek shapes that are larger than females. When standing they can be around 5 feet tall. Females weigh around 100 pounds but males can weigh up to 220 pounds. They eat mostly fruit but sometimes eat insects and flowers as well. They keep detailed maps of the forest in their mind so that they know where to go to find fruit instead of wasting time looking for it. When they can’t find water they chew up leaves to make a sponge that will soak up water. Some orangutans put sticks in their mouths which they use to get honey out of holes in trees. Orangutans live to be about 50 years old. They sleep in nests up in trees that they build every night.

Orangutans are capable of brachiating, a certain way of swinging from tree to tree. This is a good 360 video of sanctuary workers teaching orangutans how to move in the trees. However, they prefer to walk or climb from tree to tree. This method of movement in the trees allows them to distribute their weight and it’s safer. On the ground, they walk slowly because of their long arms. When they move on the ground they walk on all fours.

Fun Fact: In Indonesian and Malaysian languages, orangutan means “person of the forest.”

There are two different types of orangutans, Sumatran and Bornean. They are difficult to tell apart but Sumatran orangutans are sometimes lighter in color. They live anywhere from swamp forests to the mountains.

Orangutans are solitary primates and so their vocal systems aren’t as complicated as other primates. They use facial expressions and body movement to communicate more than they are vocal. The males have a long call which can be heard even half-a-mile away and use it to attract a mate or mark their territory. Their are also cultural sounds which are heard in some groups of orangutans but not others.

Orangutans also use many tools, such as sticks which they change so that they can use them to break open seeds.

Although orangutans are solitary, they are still social. When there is lots of fruit, they often come together and are social. Females travel with their children and while they don’t have tight groups with other females, they do know other females in the area. Males have large home ranges that overlap with that of females and they come together to form a group when they mate. Their social structure depends on how food is distributed. They spread out so that there is more to eat but when an area has a lot of food, they come together.

Orangutans usually have one child that stays with them for around 7 years. This is because they have to learn about what food they can eat. Their mothers have to teach them which fruits grow where and in what season. They learn about hundreds of varieties of fruit.

All types of orangutans are endangered but Bornean orangutans are at the most risk. In the last 60 years their population has declined by over 50% and in the last 20 years their habitat has decreased by 80%. Orangutans are hard to track because of they live in dense forests with low visibility. Sumatran orangutan population has declined over 80% in the past 75 years. Habitat loss is a major threat to orangutan populations. Indonesia and Malaysia have a large logging industry that requires them to clear land and ruin the habitat of orangutans. Young orangutans are also in danger of becoming pets, Southeast Asia has a large illegal pet trade. The World Conservation Union has declared orangutan trade illegal. Orangutans are not only important to the environment, serving as dispersers of seeds for plants, but are also a key look into evolution. Their preservation is important. You can help by donating to or adopting an orangutan from the Smithsonian’s National Zoo and Conservation Biology institute or donating to or adopting an orangutan from the World Wildlife Foundation.

“Orangutan.” Smithsonian’s National Zoo and Conservation Biology Institute, nationalzoo.si.edu/animals/orangutan.

Orangutan. Wild For Life, wildfor.life/species/orangutan.