In the meanwhile, the foundation has also released five orangutans from the rehabilitation center in Samboja Lestari in East Kalimantan to Nyaru Menteng, which is located in the Central Kalimantan province.
"The release (of the orangutans to their natural habitat) this time was done to mark Earth Day, which is commemorated across the world on April 22," Paulina L. Ela, the BOS foundation spokesperson, stated here on Friday.
She reported that the five orangutans who were re-introduced to their natural environment in Nyaru Menteng are Farudz, an 18-year-old male; Saswoko, a 16-year-old male; Friska, a 17-year-old female; Inou, an 18-year-old male; and Nike, a 17-year-old female.
"They have to be released into the wild in Central Kalimantan because it is where they came from," asserted veterinarian Agus Irwanto, the manager of the Samboja Lestari program.
Farudz and his colleagues belong to the Pongo pygmaeus wurmbii species, which is the sub-species of Pongo pygmaeus, living in the forests of Central Kalimantan.
They mostly have a bigger physique as compared to Pongo pygmaeus morio, the sub-species that live in East Kalimantan.
Farudz, who is the biggest, weighs 75 kilograms and has an arm stretch of up to 170 centimeters, he reported.
Agus pointed out that Farudz and the other orangutans will firstly be released into Nyaru Menteng to see if they can adjust to the surroundings, before being sent to the Bukit Batikap protected forest on the Schwanner hill within the Murung Raya district administration.
Other orangutans to be released into Nyaru Menteng were Slame, an 18-year-old male; Olympia, a 16-year-old male; Kiki, a 20-year-old female, and her 8-year-old son Hardi.
Slamet and his friends will be flown in from the Tjilik Riwut airport in Palangka Raya, Central Kalimantan, to the Beringing airport in Muara Teweh, from where they will be flown by helicopter to Bukit Batikap.
The conservation of orangutans is part of the increasing efforts to meet the target set in the 2007-2017 Indonesia Orangutan Conservation Action Plan and Strategy.
The action plan was launched by the Indonesian president at the climate change conference in Bali in 2007.
Based on the plan, all orangutans in rehabilitation centers must be released to their natural habitat by 2015, at the latest.
Since 2012, the BOS Foundation in Nyaru Menteng has released a total of 119 orangutans to their natural habitat in Bukit Batikap.
With the latest release of 12 orangutans by the BOS Foundation to Bukit Batikap, the tally now reaches 131.
Reporting by Novi Abdi
EDITED BY INE