Berlian Heard a Long Call from Wild Orangutan

On November 19th, 2012, our monitoring team conducted a special mission to monitor Berlian’s activity for the whole day. As usual, our team will record every single activity precisely. Berlian is slightly different from the other orangutans, instead of exploring the forest on a fast pace; she prefers to linger to enjoy her food. After finding her morning nest, the team began to record her activity.

That morning, Berlian started her day with a breakfast of Uncaria glabra. Uncaria is locally called Gambier. Its extract powder is usually used by humans for tanning or dyeing. Her favorite parts were obviously the young leaves, young stems, and cambium bark. In addition, she also enjoyed young leaves of Etlingera Sp. (forest ginger), Calamus Sp. (bamboo), and Ficus Sp. (banyan tree). And she did all this feeding activity without even moving too far from her morning nest.


Berlian enjoying the forest

At approximately 4:25 pm, the team was surprised by the sound of a long call from a wild orangutan. Consisting 12 grumbles (breath sounds before the long call), 47 long calls and 32 bubbles (sound produced after long call as a neutralizer). This phenomenon is inline with RHOI’s team survey result a while ago describing the finding of several-abandoned nests of male wild orangutans in the area of Kehje Sewen Forest.

While the team was surprised by this sound, Berlian looked alert. She stopped eating for about two minutes. As the long calls grew louder, Berlian was getting scared. Form its loudness, the team estimated the presence of the wild orangutan was about 150 meter from where Berlian was located. The team also saw when the wild orangutan uprooted a tree (snag crash). Berlian huddled with her head between her legs, holding on to herself tightly. But after 10 minutes had passed and the long call did not come again, Berlian was back to her activities. In the next few days however, Berlian still occasionally revisited the place where the noise came from, to check things out.


Wild Male Orangutan’s Nest

According to Dr. Sri Suci Utami, a well-known primatologist in Indonesia, Berlian’s behavior is normal. Although this is not the first time Berlian experiences a long call from an orangutan (she heard it plenty of times when she still lived in Samboja Lestari), but to experience long calls in a real forest would be very different. Other factor that influences this behavior is that, an immature female orangutan like Berlian (10 years old) tends to be attracted to males who are also in their age range, without cheek pads and do not produce long calls. This is why Berlian looked very frightened when she heard the sounds of long call of the wild orangutan.

Minutes went by, Berlian was back to her activity. Once satisfied with the various types of young leaves, Berlian then started harvesting honey from a beehive on a Liana tree next to her. As expected, some of the bees became angry and attacked Berlian. The bees stroke her hand, foot and neck, but she still looked relaxed, simply enjoying the honey. Berlian was just rubbing the sting. While continuing to enjoy the honey, at 5:25 pm Berlian started to make a nest. Soon after finishing her ‘dessert’, Berlian seemed to rest in her nest.

The team then returned to Camp 103 joyously. The long call of the wild orangutan proves Kehje Sewen’s biodiversity.


A Beautiful Rainbow Seen from Camp 103

Photos by: Wulan, Agus and Rio


Samboja Lestari Orangutan Release Candidate Profiles


Emerson was already a young adult of around 15 years old when he was rescued in Sangatta and taken to Samboja Lestari on February 11, 2001. Due to his size as well as our capacity in Samboja Lestari, which at that time had reached its maximum, Emerson was placed in an individual enclosure.

Although he demonstrates a healthy dislike towards humans, during his years at Samboja Lestari, Emerson has turned out to be very gentle towards female orangutans. He is also kind to other orangutans in general and was hence moved to a pre-released island. The island was already occupied by Leo and “his gang”, and so we observed the group closely for quite some time as a precaution. But Leo welcomed Emerson and was actually quite intrigued by this giant new male with big striking cheek-pads. Emerson responded coolly but was clearly glad that his presence was not challenged. Although the two never become best buddies, they have never been aggressive towards each other. While Leo courts Juminten, Emerson has developed a close relationship with Sarmi. Life is good on the island. Now, 26 year-old Emerson is preparing for his final journey. Emerson is finally returning to his rightful home!


Rescued from an industrial forest owned by PT Surya Hutani Jaya (SHJ) in Sebulu on the border of Kutai National Park, Juminten at that time was only 6-7 years old. At this age, orangutans in the wild are considered teenagers as they are usually already independent from their mothers. The female teenager Juminten was found in a block of industrial acacia trees and was taken to BOS Foundation’s rehabilitation center in Samboja on April 12, 1998.

Following initial health checks Juminten needed initial medical treatment. In 2010 Juminten was moved to a pre-released island where she met Leo. The two have been courting for a while now. An interesting note about Juminten is that she is often seen lovingly babysitting and taking care of another female orangutan’s baby when the mother is unwell. Juminten is now a beautiful 21 year-old and is as wild as ever. And her time has finally come to return to the wild where she belongs!


Leo is a male orangutan who was rescued when he was aged 4-5 years old from Sebulu, one of the areas in East Kalimantan which was devastated by forest fires in 1997/1998. He was taken to Wanariset-Samboja (previous name of Samboja Lestari) on September 26, 1997. Leo demonstrated very wild behavior indicating that he had not had much contact with humans. After spending quite some time in a socialization enclosure, Leo was finally relocated to a pre-release island, Island 3, in 2009. Leo immediately embraced life on the island wholeheartedly. He adjusted quickly and was soon actively climbing trees, making nests, and demonstrating his ability to find forest foods.

In 2010, we introduced Leo to some females – Eliza, Mona and Juminten. Again, he showed encouraging behavior and was very gentle and playful in his approach to them. Leo was obviously attracted to Juminten, but with Mona and Eliza, he played  more of a big brother role. Leo’s progress has convinced us that he is ready for a life in a real forest.  Now at 20 years old, the handsome male with huge cheek-pads is soon going home!


Titin is a female orangutan who first came to Samboja Lestari on March 9, 1994. Rescued in the capital of East Kalimantan, Samarinda, she was 4-5 years old. In 2000, Titin delivered a baby boy, Titon who lived with his mother until he was 7 years old. After Titon was moved to be with orangutans his own age, in 2008, Titin had her second baby – a baby girl this time – named Tina-Toon. At the end of 2010, Titin and her daughter Tina-Toon were moved to a pre-released island, joining Leo and Juminten among others.

Now that Tina-Toon has left her mother to join Forest School, Titin seems to progress a lot quicker in terms of developing her forest skills. Although she is not as dominant as Juminten, on the island Titin is second in command. However, Titin does not show repressive behavior towards younger orangutans on the island. She is generally a kind orangutan who also has an on-and-off love interest with Leo which Juminten does not seem to mind at all. Her island life has been good and rewarding. But at the age of 23 years old, Titin will soon embark on her final journey home.


A young female orangutan of 4-5 years old was rescued near a coal mine in Sangatta. That year, 1998, many coal mining companies aggressively expanded their operations in the area resulting in overwhelming habitat loss for many wild animals, including orangutans. On a positive note though, some companies did take responsibility for their actions by extensively funding and facilitating rescue activities. They were also actively involved in many awareness-building programs in the area.

Named Sarmi, this young female orangutan was taken to Samboja Lestari on October 6, 1998. With Mona and many other orangutans rescued during that period, Sarmi grew up in a socialization enclosure until 2010, when she was moved to Island 6, a pre-release island at Samboja Lestari, along with four other females, two mother-child pairs and an orphaned baby male orangutan named Saprol. By that time, Sarmi already had a young daughter, Sani who was born in 2005. Unexpectedly, Sarmi adopted Saprol! She raised and cared for him as her own son and as a brother to her daughter Sani. Earlier this year, we introduced Sarmi to Emerson, a huge and gorgeous male and also one of our current release candidates. The two bonded quickly and have since developed a wonderful relationship. We can’t wait to see these two orangutans take their relationship to a new level when they are both released in the forest!


Little Mona was 4-5 years old when she first came to Samboja Lestari on September 28, 1997. Rescued in Tenggarong, Mona was such a beautiful orangutan with round face and dark maroon hair typical of East Bornean Orangutan (Pongo pygmaeus morio). Growing up with friends of the same age in a socialization enclosure, Mona finally earned a place on a pre-release island in 2010, where she quickly learned forest skills from Leo as well as from other older orangutans. She paid special attention to Leo especially when he was making a nest and seemed to make a mental note of the types of branches and leaves Leo used to make his nest. Pretty soon, Mona could build a nest as sturdy and comfy as Leo’s!

She is obviously a very smart orangutan. She has also steadily demonstrated her ability to climb, swing and identify yummy forest foods. Although on the island Mona is at the bottom of the hierarchy, big brother role model Leo is quite fond of her and often lets her build her nest in the same tree as his. The other females are also very tolerant with Mona and love to play with her. Only Juminten keeps her distance from Mona obviously to maintain her dominant position. Even so, Juminten too is never aggressive towards Mona showing that Mona is a sociable and likeable orangutan. Beautiful Mona has become an independent adult and now at 20 years old, Mona is more than ready to be reintroduced back into the wild.