Once found throughout much of Southeast Asia, the red ape now only survives in small populations in increasingly fragmented patches of forest on the islands of Borneo and Sumatra. There are two species of orangutan: Pongo abelii in Sumatra and Pongo pygmaeus in Borneo. Within Borneo, Pongo pygmaeus is divided into three further subspecies: Pongo pygmaeus morio in Sabah and East Kalimantan, Pongo pygmaeus wurmbii in central and southern areas, and Pongo pygmaeus pygmaeus in Sarawak and the North West. There are estimated to be only around 6000 orangutans left alive today in Sumatra, and just 45 - 50,000 individuals left in Borneo.
Orangutans can live up to 40 years in the wild and often longer in captivity. The adult males are much larger than the females. The average female adult weight is around 40kg while males can be double that. They’re semi solitary primates that depend on an incredibly varied natural diet from literally hundreds of different plant species. A fully flanged dominant male ranges over a very large territory, attracting local females for mating with his distinctive ‘long call’ which can be heard across the forest. The gestation period for orangutans is around eight and a half months and a mother will typically spend between 6-8 years rearing and teaching its offspring the skills necessary to survive independently in the forest. A female may have just two or three babies in its lifetime which means orangutans as a species struggle to repopulate as their numbers decline.
Living & feeding
Orangutans live most of their lives high up in the tree canopy and their bodies are perfectly evolved for this. While they have no tails and do not jump, their massive arm spans, incredible strength, elongated and curved fingers, and their gripping feet mean that they’re easily able to move around in the treetops by reaching, swinging, or climbing from tree to tree. Swinging through the canopy hand over hand helps to give orangutans such great arm strength, and this form of locomotion is called 'brachiation'. Each night they make nests to sleep in by breaking and folding branches high in the treetops. They often make these more comfortable by loading them with lots of leaves to act as their mattress and pillow.
An orangutan will typically spend around half of its finding food. They are frugivores, which means that they generally prefer to eat forest fruits whenever they are available. When the forest is in low fruiting season however, they’ll increase the amount of leaves, barks, piths and insects in their diets. As a species overall, orangutans are known to have eaten around 400 different plant species. This also helps to explain why they have also evolved such great intelligence as they commit to memory an incredibly detailed maps of the forest, and document where and when certain trees bear fruit during the year throughout their large home ranges.
Why do they need our help?
Asia’s only Great Ape species has been in decline over recent decades for a variety of reasons, but the loss of their preferred lowland habitat is the most significant factor. Forest degradation, often a precursor to deforestation, starts with the establishment of a network of logging roads, which open up vast tracts of previously inaccessible forest for timber extraction and mining. Once valuable wood stocks and minerals have been exhausted, forests can be cleared to make way for industrial oil palm, acacia and rubber plantations.
Indonesia and Malaysia, which is home to orangutans, produce 90% of the world’s palm oil. Palm oil is so popular because it has the highest per hectare yield of all edible oils, as such around half of all supermarket products now contain it. Oil palm monocultures, however, harbour just a fraction of natural biodiversity when converted from lowland rainforest. Poor land use has also led to the widespread fragmentation of remaining natural forests, which leaves little pockets of land with no connecting forested corridors for the apes to travel along. This isolation of wildlife populations is a major factor in creating conditions which cause local extinctions due to reduced gene flow and foraging opportunities, and a general increase in competition for remaining resources.
Forest fires, usually started by plantation companies to clear land, can also burn large areas of forest, which took thousands of years to form, in just a few hours, destroying habitat for orangutans and countless other species. As the rate of deforestation and fire has increased, so have human-orangutan conflicts, as starving, displaced animals raid plantations and village small holdings in search of food, where they are often killed. But orangutans are also poached from the wild for a variety of other reasons, either for food, for the pet trade, for their supposed medicinal value, or to supply the entertainment industry with cute mascots.
Due to the combination of these threats the Bornean orangutan is now officially Endangered, and the Sumatran orangutan is critically Endangered according to the International Union for Conservation of Nature (IUCN). They are a species close to extinction and they need our help