Located in the east of the Aceh province, Sumatra, the Pinus Jantho Nature Reserve is one of only two release sites where Sumatran orangutans are now being released into the wild. Surveys conducted between 1990 and 2009 did not identify any orangutan population in the Pinus Jantho Nature Reserve and also showed that the forest area here is identical with the original orangutan habitat found in other areas in Aceh. The site is a protected area of exceptionally rich lowland forest, with an unusual high density of fig trees, a staple food for orangutans. There is also a river which is at the foot of the forest, which can be crossed by people, but cannot be crossed by orangutans making it an effective natural barrier. The connectivity of the nature reserve to the wider forest block called Ulu Masen (circa 75,000ha and ultimately connected to the vast Leseur Ecosystem, in which 85% of Sumatra’s remaining wild orangutans reside) make this reintroduction site an ideal are for orangutans.
Orangutans that are released at the Jantho site have been previously confiscated and housed at the Batu Mbelin Orangutan Quarantine Centre in North Sumatra. Staff choose orangutans to be released based on their health, behaviour and potential to survive in the wild. All orangutans in the release programme are given a full health assessment and have a small transponder inserted between their shoulder blades so they can be tracked using telemetry equipment well after their release to check on their progress. The orangutans must also be able to show signs of natural orangutan behaviour including nest building and eating a range of foods before they are considered for release.
Once orangutans are transported to the Jantho release site, they spend some time in large reintroduction cages so they can become used to the conditions and surroundings. The staff collect natural forest foods for the orangutans to eat and become familiar with before they are released. Each orangutan is monitored closely after being released with trackers following them from dawn until dusk when the orangutan makes a sleeping nest for the night. Data is recorded including what foods the orangutans eat and this information will be used to assess the survival capability of the reintroduced orangutans.
The first orangutans were released into the Jantho Nature Reserve in 2011 and now over 30 orangutans have been successfully released. A plan for engaging local communities is currently being established to tackle the issues of land encroachment activities. This release area provides hope and a second chance at living in the forest for confiscated and displaced Sumatran orangutans.