The Ministry of Forestry of the Republic of Indonesia, the Natural Resources Conservation Agency (BKSDA) of East Kalimantan, and the Borneo Orangutan Survival (BOS) Foundation—with support from Riau Andalan Pulp and Paper (RAPP)—are preparing for the 27th orangutan release from the Samboja Lestari Rehabilitation Centre into the Kehje Sewen Forest, an ecosystem managed by PT. Restorasi Habitat Orangutan Indonesia (PT. RHOI). Here are the candidates for this special release:

Sie-Sie (Male)

Sie-Sie is a 31-year-old adult male orangutan who arrived at the Samboja Lestari Rehabilitation Centre on August 27, 1996, when he was just 1–2 years old. Originally from Semarang, Sie-Sie was confiscated and brought to the centre for rehabilitation. Interestingly, due to his delicate features, Sie-Sie was initially mistaken for a female. However, over time, his behaviour and physical development—including a growing cheek pad typical of dominant males—revealed his true identity.

Throughout his rehabilitation, Sie-Sie has made tremendous progress, especially in nest-building skills. Now, after nearly 29 years of care and learning, he is ready to return to the forest and will be released alongside five other orangutans.

Siti (Female)

At 35 years old, Siti has one of the longest and most remarkable journeys. She re-entered the rehabilitation program on December 8, 2022, after previously being released in 1997 into the Sungai Wain Protected Forest and later relocated to the Gunung Beratus Protection Forest.

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Her return to the centre came after BKSDA SKW III Balikpapan received a report from employees of PT. Balikpapan Wana Lestari about an orangutan frequenting their worksite and interacting with staff for several consecutive days. The BOS Foundation team rescued her in Muara Toyu, Paser Regency. Now, Siti is ready to return to the wild in April, reclaiming her freedom in the Kehje Sewen Forest.

Uli (Male)

Uli, a 28-year-old male orangutan, rejoined the rehabilitation centre on June 11, 2022, after being rescued from Loesan Village, Paser Regency. He was originally part of the BOS Foundation’s program at the government-owned Wanariset research station and was released into the Gunung Beratus Forest on September 9, 1999.

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Years later, videos of Uli being fed by villagers—bananas, jackfruit, and canned milk—circulated widely on social media, prompting a rescue operation. After two years of renewed rehabilitation, Uli is once again ready to embrace life in the wild.

Mikhayla (Female)

Mikhayla, a ten–year–old female orangutan and the youngest member of this release group, was rescued near the Sangatta–Bengalon highway within a mining concession operated by PT Kaltim Prima Coal. Severely malnourished and showing signs of prolonged stress at the time of rescue, she was found dangerously close to the main road connecting Bengalon and Muara Wahau.

Her rescue on January 12, 2025, was made possible through a coordinated effort involving the East Kalimantan Natural Resources Conservation Agency (BKSDA Kaltim), the BOS Foundation (BOSF), the Centre for Orangutan Protection (COP), and the Conservation Action Network (CAN). Upon arrival at Samboja Lestari, Mikhayla received immediate veterinary care, including nutritional supplements and deworming treatment.

After just three months of intensive rehabilitation, she has made a remarkable recovery and is now ready to begin her new life in the Kehje Sewen Forest.

Bugis (Male)

Bugis, now 33, arrived at the Wanariset facility on July 3, 2003, from Ujung Pandang at about 10–11 years old. Known for his assertive nature, Bugis was placed in the Socialization Complex where he received special care and enrichment from the BOS team.

Though aggressive toward other orangutans—once even displaying dominant mating behaviour—Bugis is calm and obedient around his human caregivers. After 22 years in rehabilitation, he is finally ready to be released into the wild alongside his peers.

Orangutans Returned to Kehje Sewen

In addition to the five orangutans above, the Ministry of Forestry and the BOS Foundation also re-released female orangutans that had previously been released in the Kehje Sewen Forest in 2019.

Mori (Female)

Mori, a 16-year-old female, was originally rescued from Sangatta and transferred to Kutai National Park before being moved to Samboja Lestari on February 24, 2012. She was just 2–3 years old at the time and without her mother. Despite her traumatic start, Mori grew into a self-reliant orangutan who prefers to avoid human contact.

She was released into Kehje Sewen in 2019, but due to deteriorating health from melioidosis, she had to return to the centre for treatment. Now fully recovered, Mori is ready to return once again to her true home in the wild.