BOS Foundation: Never a Dull Moment with Orangutans

Text by: PRM Team in Lesik Camp, Kehje Sewen, East Kalimantan

January 25, 2021 — Our Post-Release Monitoring (PRM) team at Lesik Camp, in the Kehje Sewen Forest of East Kalimantan, has a plethora of stories to tell from their experiences observing released orangutans. Since orangutans are extremely intelligent great apes with unique individual personalities, each day can bring the unexpected and their behaviors are always fascinating to observe.

During their work, our teams have experienced the full range of encounters, from the exciting and fun, to the tense and unnerving. The behavior of a rehabilitated orangutan, due to their past trauma, can change in a moment’s notice. It is possible for an orangutan to fall into a seeming ‘routine’ of behaviors for a few days, but then appear to completely change their behavior the next day. It can be made even more confusing, as the factors that trigger these changes are not always clear to the PRM team.

This means that it is very important to know the personalities of each individual orangutan, especially those who can be aggressive. One of these orangutans is Mona, an extremely curious female who also has a strong dislike of humans.


In addition to Mona, there is also Marlies, another female who dislikes humans. Her hair will easily rise, as her skin is covered with goosebumps when she spots humans, indicating her anger. When in this agitated state, Marlies can be unpredictable, so the team always stays alert and will take the necessary precautions to avoid an unexpected run in with her. In the worst case scenario, the team can simply jump into the river, as it is the only place orangutans can’t reach due to their inability to swim. When Marlies knows there is a barrier between her and the humans, she always calms down and moves on.

A number of clever and curious orangutans that we observe are drawn to the equipment we carry. Despite deliberate attempts to avoid taking colorful items into the forest that might attract an orangutan’s interest, there are some determined and sly individuals that still find ways to catch us off guard and satisfy their curiosity by stealing our things. In this area, Robert and Ung are the masters! We have to be very careful to keep a close eye on their movements when observing them to avoid any theft!

We are highly impressed with the ability of these released orangutans to adapt to their forest environment, where they face daily competition and challenges. We know that the attributes that make our job a bit more difficult, such as a dislike for humans and boundless curiosity, are still positive as they increase these orangutans’ ability to face any challenge that life in the forest may bring to them. May these released orangutans live prosperously in their natural, wild home!

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