Orangutans spend a long period of time with their mothers before they can be fully independent. During that time, they need to learn all the vital skills that will allow them to survive by themselves in the forest. This knowledge is passed from mother to child. However, in the event of the death of the mother, the staff must provide the environment and the right experiences to the orangutans where they are able to learn all these skills, and at the same time, they teach the orangutans what the mother would do. Depending on their age, psychological condition and pre-knowledge, the orphan orangutans start at different levels of the rehabilitation program and these are the vital skills they will need to learn in the program to ensure their survival once they will be released.

This is one of the most important skills for an orangutan to learn, to be able to survive in the forest independently. According to Schuppli et al. 2021, wild orangutans individually consume around 100-200 food items; they are mainly frugivores, however they also eat leaves, flowers, piths, stems, bark-cambium and insects. Therefore, young orangutans need to learn what is eatable in the forest and avoid the plants that will harm them. They also need to learn where they will find the food and when is the season for each type of food, since at certain times they will need to rely more on leaves and bark-Cambium.

The teams onsite undergo botany training in order to learn about local plant species and which ones are safe for consumption by orangutans. Then they must transfer that knowledge to the orangutans taking the approach as an orangutan mother would; eating it themselves in front of the orangutan, which will bring curiosity to the orangutan and enable them to imitate their surrogate mothers.

The primary objective is to release orangutans into a life in the wild and it’s essential for their survival that they do not believe that all humans are good to them. That is why they take extreme care to limit the exposure of the orangutans to humans outside of the caretakers and orangutans must learn to discriminate between familiar, trustworthy humans and strangers whom they must not trust but avoid. 

Further on, they will need to recognize the dangers in the forest and how to avoid them, so they don’t get close to snakes or other dangerous animals. 

When they want to teach orangutans that something could pose a threat, they do as their mothers would: They go into hiding or try to repel the danger by shaking a tree, or a branch and giving warning orangutan calls.

Wild orangutans build nests on an almost daily basis as a place to sleep at night or as a place to rest during the day. Resting in a nest in the trees provides more comfort to the orangutans, helping them in their mental and physical recovery while sleeping. The nest also has an anti-predator role, because it gives some camouflage and they are high up in the trees.

Nests also reduce the risk of annoying insects that can bring diseases to the orangutans, such as ticks or mosquitoes, and moreover, the nest also provides more thermoregulation while sleeping. For all these reasons, it is very important that the orphan orangutans learn how to build a nest and get used to sleeping surrounded by leaves. The caregivers do daily nest-building classes for the orangutans, modelling and encouraging them to build nests by themselves.

Orangutans are arboreal primates, meaning they mostly move among the trees and their body is adapted to it with big shoulders, long arms, and feet that are more similar to hands so they can hold branches and trunks with them. The orphans need to have the right environment where they can practice how to move in the canopy, learn which branches are safe for their weight, and which ones could break, as well as the safest way to transfer from one tree to another depending on the tree fortress. That is why the ORANGUTAN FOREST SCHOOL, conducted by our partner Yayasan Jejak Pulang in cooperation with the Indonesian Ministry of Forestry, is the ideal surrounding for them to learn this kind of locomotion; however, for us as humans, we cannot fully teach them how to do that. Instead, what we can do is be high in the trees ourselves with safety climbing equipment and encourage the orangutans to stay up in the trees to practice their arboreal locomotion.

Even though orangutans are known as semi-solitary animals, they also have social encounters while they are in the wild, and developing social skills is essential for them so that they can live in the wild with other orangutans. It is important they have experiences not only with other orangutans from the same age group, to play and explore the environment, but also with older and younger orangutans – this gives them skills in how to read body language and when they can be the stronger or weaker playmates. 

They also can learn vital survival skills as nest building, locomotion, or finding food from other orangutans. That is why in the FOREST SCHOOL, they sometimes mix individuals from different skill levels, always under the supervision of the surrogate mothers. These experiences with other orangutans help them to not only develop their social skills, but they will also learn other orangutans skills from each other.

Orphaned Orangutans need to learn to recognize the meaning of natural orangutan calls and the difference between a playful sound and aggressive or intimidation sound. Caregivers learn the typical orangutan call repertory that has been defined by researchers and display them in the right situations. 

For example, one very important vocalization for orangutans is called “kiss squeaks”. This sound is similar to the human kiss sound, however orangutans can use this sound to demonstrate dominance towards one another or to scare away predators or other dangerous animals. They can even accompany this sound with a movement of their hand or leaves on the lips to make the sound even louder. 

Therefore, it is very important that the caregivers use this sound in the right context so that the orangutans can learn to use it and understand it in the right way as an intimidation sound towards predators and not as a friendly sound.