WHERE DO ORANGUTANS LIVE?

Orangutans are now only found on the two islands of Borneo and Sumatra.

Fossil evidence suggests that during the Pleistocene era, from around 1.8 million years to 11,500 years ago, orangutans lived throughout much of Southeast Asia, from Java in the south, up into Laos and southern China.

The preferred habitat of orangutans is low-lying peat swamp forest.

the three species of orangutan

There are three species of orangutan, the Bornean orangutan (Pongo pygmaeus), the Sumatran orangutan (Pongo abelii) and the Tapanuli orangutan (Pongo tapanuliensis).

Orangutan adaptationS

Orangutans an arboreal species, which means that they spend most of their life living in the forest canopy.

They are perfectly adapted to this lifestyle with long, strong arms and hands-like feet to help them grip branches as they swing through the trees.

Every night, orangutans build a new nest to sleep in, often close by the last tree they foraged from.

THE DIET OF ORANGUTANS

Orangutans are frugivorous (fruit eating), but in times of poor fruiting are known to eat over 200 types of food such as bark.

They are known as ‘gardeners of the forest’ because seeds are excreted as they travel around the forest, eventually growing into new plants.

Intelligence and tool-use

Like all great apes, orangutans have large brains and are self-aware beings who are capable of reasoning. In the wild, orangutans use tools such as sticks to extract insects to eat. They are the only ape that use leaves as an umbrella during rainfall.

In captive or semi-wild conditions orangutans have been taught to use sign-language, demonstrating their vast capacity for learning and understanding. Local lure say that orangutans can speak but choose not to for fear of being put to work.

HOW MANY ORANGUTANS ARE THERE?

Being arboreal, orangutan population numbers can be difficult to estimate. Numbers are estimated by counting nests built in the treetops.

According to the most recent Population and Habitat Viability Assessment (PHVA) in 2016, there are an estimated 57,000 Bornean orangutans, 13,000 Sumatran orangutans and 800 Tapanuli orangutans left in the wild. Approximately 80% of these orangutans areliving outside of protected areas.

Social behaviour

Orangutans are semi-solitary, which is unique among primate species. This is most likely due to competition for food, as trees don’t bear enough fruit for large groups.

The only time you will see orangutans together in the wild are as a family unit, consisting of a mother and her infant(s), or as a pair of orangutans engaged in courtship.

Courtship lasts 3 to 10 days. The male plays no part in the upbringing of offspring.

Orangutan life stages

Orangutans are the slowest breeding of all primates. On average, they give birth every 7 to 8 years - the longest interbirth interval of any land-based mammal.

The reason for this long interval is that there is so much to learn about the map of the forest, where to find food and which is safe to eat. Being solitary, the mother and infant form a very special bond during this time.

Wild orangutans will normally have no more than 3 to 4 offspring in their lifetime. The low reproduction rate and long interbirth intervals of orangutans puts them at considerable risk of extinction.

CLIMATE CHANGE

Climate change presents a threat to all life on Earth. For orangutans, both increased temperatures and longer rainy seasons have altered forest fruiting patterns. Standing forests, especially peat swamp forests, store significant amounts of carbon. When this carbon is released by the destruction of forests, it accelerates climate change.

Oil-palm plantations

Indonesia is the world’s largest palm oil producer. Palm oil is a type of vegetable oil produced from the kernels of oil-palm trees. Orangutan populations are threatened because their habitat has been cleared and converted to oil-palm plantations. In recent years, sustainable palm-oil is being produced more on previously degraded land rather than cutting down primary forest.

LOGGING

Logging concessions can sustain populations of orangutans when they are well managed. However, illegal logging has been a major and complex problem in Indonesia. Due to large-scale deforestation, Indonesia is one of the world’s biggest emitters of greenhouse gases

Mining

In recent years, mining has caused irreversible damage to Indonesia’s forests. Illegal open cast mining for coal, iron-ore and nickel in protected areas has turned the lush primary rainforest into barren and lifeless deserts. Mercury which is used some mining processes contaminates river systems, killing fish and other wildlife.

Forest Fires

Fires have been traditionally used for slash and burn farming (small-scale shifting cultivation). However, when the fires coincide with an El Niño year (which results in a longer than normal dry season), they can become out of control and lead to widespread wildfires. This is especially the case in peat forests as the organic material is extremely flammable and can be difficult to extinguish.

Human-Wildlife Conflict

As communities expand, forests shrink, and the wildlife within risks increasing conflict with humans.

In the past, hunting was the main human-wildlife conflict. Today, the orangutan is protected under Malaysian and Indonesian law, and it is illegal to own, harm or trade an orangutan in these countries.

Now, the issue is one of coexistence. Many communities surrounding the forest rely on it for their livelihoods. However, unsustainable practices can leave the habitat severely degraded.

Learn more about our work with local communities to reduce harmful agricultural practises and human-wildlife conflict.