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Together, the Ministry of Environment and Forestry (KLHK), the East Kalimantan Conservation and Natural Resources Agency (BKSDA), and the Borneo Orangutan Survival (BOS) Foundation have successfully released five rehabilitated orangutans into the Kehje Sewen Forest ecosystem restoration concession.

This release comes after a two-year break in release activities by the BOS Foundation in East Kalimantan, with the prior release in the area taking place on February 18, 2021. The newest release operation started on May 16, 2023 and ended successfully with the five orangutans proving they have finished the long rehabilitation process at the Samboja Lestari Rehabilitation Centre, East Kalimantan, and were ready to live in their true forest home.


Although the World Health Organization (WHO) lifted the emergency status of the COVID-19 pandemic on May 5, the BOS Foundation continues to strictly implement health protocols for the release of new orangutans. The well-designed release scheme went smoothly despite some unexpected hurdles. 

The team left by car for Muara Wahau from Samboja Lestari Rehabilitation Centre around 11.00 AM local time. After taking approximately 12 hours to arrive at the first stop, the team continued their journey to Pier 67 and crossed the Telen River. This pier is our team’s main gateway to the release points in the Kehje Sewen Forest.

However, reaching Pier 67 is no easy task. As they traveled the dirt roads, the team encountered a landslide that had damaged the already fragile bridge. At this point, all of the human passengers had to exit the cars and continue on foot. Meanwhile, the skilled drivers had to very carefully navigate what little had remained intact for the sake of the orangutans watching from their transport cages in the flatbed. The painstaking crossing was worthwhile, as all vehicles made it to the other side where the team finally loaded the orangutans into the motorised boats that awaited them. One by one the cages were moved to the opposite side of the Telen River, to the release point.

After a 20-hour journey by land and river from Samboja Lestari Rehabilitation Centre to the south side of Kehje Sewen Forest, five orangutan transport cages were successfully opened. These five rehabilitated orangutan cages were opened at two different points. Mayer and Elaine were released at the first location, while Andreas, Leann, and Riana took their first steps in freedom at the second release point.


Andreas (Photo credit: Isna)

Passing a damaged makeshift bridge (Photo credit: Ariella Kurnia)

The release team waited for their turn to cross the Telen River (Photo credit: Paulina L. Ela)

The transport cage is lowered from the motorboat (Photo credit: Isna)

Walk towards the release point (Photo credit: Isna)

Elaine cage was opened (Photo credit: Ariella Kurnia)

Leann cage was opened (Photo credit: Ariella Kurnia)

Mayer (Photo credit: Ariella Kurnia)

Riana (Photo credit: Ariella Kurnia)

PRM-RHO Team (Photo credit: RHOI-BOSF)

The first cage opened was Mayer. This male orangutan aggressively displayed towards the team, which is not uncommon as each orangutan copes with the long and stressful journey in their own way. Once he settled down, just like the others, all he wanted to do was eat the remains of the food provisioned by the journey before finally finding a tree where he could feed on wild fruit and leaves.

For Elaine, her reaction to the transport cage opening was completely different. She immediately started to explore her new environment, as she climbed into nearby vegetation. Her first stop in the Kehje Sewen forest was the comfortable branches of a rasamala tree (Altingia excelsa).


Andreas's transport cage was opened at the next release point. The active Andreas immediately climbed the tree in front of him and made a nest, however, his rest came to an end the moment Leann's transport cage was opened. He went to greet his new neighbor and make his interest in her well-known, ending with the new pair copulating. We could not be more proud of Andreas and Leann already making themselves at home and trying to naturally grow the number of orangutans in Kehje Sewen!

The final cage opened was that of Riana. She emerged and did not take immediate action, instead she just took in her new surroundings before moving closer to Andreas and Leann. On their first day in the forest, the trio stayed within a few metres of one another. As the sun started to set, Riana did get to work, making a nest for herself to sleep peacefully that evening.We sincerely hope that these five rehabilitated orangutans can adjust well to their new home, the Kehje Sewen Forest. This should be no problem as the meaning of Kehje Sewen in the location Wehea Dayak language is ‘Home of Orangutans’. With the arrival of these five orangutans, the reintroduced orangutan population of Kehje Sewen rises to 126 individuals and the potential for new baby orangutans grows. Enjoy the freedom you worked so hard to achieve, Riana, Leann, Andreas, Elaine, and Mayer!

Help us to take our orangutans back to the safety of the rainforest by supporting their wild journey!

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