Orangutans are the only great ape located in Asia. Indonesia and Malaysia have the only two species of orangutans: Sumatran and Bornean. There are three subspecies of the Bornean orangutan. Borneo is sectioned off into three areas by a large mountain range: east, northwest, and southwest. Each of these areas has one subspecie.
Bornean Orangutan: Pongo pygamaeus
Sumatran Orangutan: Pongo abelli
Males and females differ greatly in size. Adult, dominant males can reach up to 200 lbs., while adult females weigh an average of 100 lbs. Adult males are roughly 4 feet tall and females can grow up to 3 feet tall. Unlike females, adult males have two phases: flanged and unflanged. Unflanged males close to the size of adult females and have the same characteristics. When the process is complete, males have cheek pads, a larger throat sac, and have almost doubled in size. It is theorized that the cheek pads help the male’s reproductive call to be louder to attract more females.
These species are mainly solitary, traveling in packs of one or two, and spends most of their time in trees. They are the largest arboreal animals in the world. Every night, orangutans make new beds out of branches and leaves in different places within their home range.
Females reach sexual maturity between 14 and 16 years of age. The gestation period lasts for 9 months. After the infant is born, it will not leave the mother for at least eight years. The mother will not have another infant for another 8-10 years. During their lifetime, a female may have 3-4 offspring.
Orangutans are frugivores. Fruits make up about half of their diet and the other half consists of bark, leaves, insects, and the occasional small mammal. Over 400 species of fruit have been documented in their diet, such as plums and figs. One of their favorite fruit is the durian. This fruit has a hard shell and spikes. The orangutan has to be meticulous and patient in order to get the meat inside.
Orangutans are known as the “botanists of the world.” They are able to remember the life cycle of many plants and the location of the trees. Besides this, orangutans, in a sense, plant the seeds from the fruits they ingest. The seeds are distributed by the orangutans has they travel through their home range. As a result, the tree populations are able to spread further than these could on its own.