A breakthrough discovery confirmed the existence of a brand new, isolated population of the Tapanuli orangutan (Pongo tapanuliensis), essentially the most endangered great ape on the planet. Previously, this small group was regarded as exclusive to the Batang Toru forest ecosystem in North Sumatra. This small group was present in a peat lavatory forest about 20 miles to the west, providing a glimmer of hope for the species’ survival but additionally highlighting a critical conservation crisis.
For years, the worldwide population of the Tapanuli orangutan, known locally as Mawas Juhut BontarIt was believed to be confined solely to the forests of the Batang Toru landscape, which covers the southern, northern and central Tapanuli Regency. However, recent research conducted by the Sumatran Orangutan Conservation Foundation – Orangutan Information Center (YOSL-OIC) revealed their presence within the peat lavatory of Lumut Maju village in central Tapanuli.
The path to this discovery began in May 2022, when an area resident reported an orangutan sighting to the YOSL-OIC Human Orangutan Conflict Response Unit (HOCRU). Although the primary field visit resulted in no direct sightings, the team discovered five orangutan nests, confirming their presence. This prompted the YOSL-OIC research team to research further.
“Follow-up monitoring carried out in October 2022 in the approximately 1,234-hectare Lumut Maju forest revealed 17 nests, some of which were newly built,” explained Rio Ardi, head of restoration and biodiversity research at YOSL-OIC. “Based on our joint survey with the North Sumatra Natural Resources Conservation Agency (BBKSDA) conducted between 2023 and 2024, we estimated the population to be five to eight individuals.”
The first direct confirmation occurred in October 2024 with the sighting of a lone male. Recently, on September 26, 2025, Mongabay Indonesia journalist Junaidi Hanafiah, accompanying the YOSL-OIC team, successfully photographed a mother and her child after a difficult three-hour hike into the forest.
To dispel any doubt that these aren’t essentially the most common Sumatran orangutans, the team collected fecal samples in January 2025. DNA evaluation conducted at a laboratory in Bogor, West Java, finally confirmed that orangutans are rare Pongo tapanuliensis species.
An ecosystem on the sting
This scientific breakthrough is overshadowed by the intense sensitivity of the newly discovered habitat. The forest is just not a protected area but has been designated as an ‘Area for Other Purposes’ (APL), which makes it legally vulnerable to land conversion.
“The situation is urgent,” Ardi warned. “In 2025 alone, we saw extraordinary land clearing. Less than 1,000 hectares of this forest remain. We are deeply concerned in regards to the fate of the orangutans there.”
The major threat is the constant expansion of palm oil plantations, carried out by each corporations and personal individuals, often using heavy equipment. Local resident Aman Rida confirmed that although the community had known in regards to the orangutans for a very long time, they assumed the federal government was also aware of it. The village’s distant location and poor infrastructure keep it isolated, but development is now entering rapidly.
Photo: Junaidi Hanafiah/Mongabay Indonesia
Ferry Aulia Hawari, a graduate of the University of North Sumatra (USU) and GIS specialist at YOSL-OIC, studies habitat fragmentation. “The Batang Toru forest and the Lumut peat forest are completely separated from each other by palm oil plantations and road construction,” he said. His research, which analyzes forest cover data since 1990, goals to quantify the devastating impact of lost connectivity.
Conservation Crossroads: Relocation or Reconnection?
The discovery sparked a critical debate amongst experts: What is the perfect strategy to avoid wasting this fragile population?
Panut Hadisiswoyo, director of Green Justice Indonesia (GJI) and an orangutan expert, believes translocation will be the only viable long-term solution. “This is great news, but their habitat is being eroded every day,” he explained. He argues that the population, probably lower than 100 individuals, is just too small to be genetically sustainable and falls far wanting the 250 individuals often cited because the minimum for a viable population. “Reconnecting the Lumut forest with Batang Toru is extremely unlikely. Relocating them to a safer block inside the Batang Toru ecosystem would increase genetic diversity and population numbers.”
However, Wanda Kuswanda, a senior researcher on the Indonesian National Research and Innovation Agency (BRIN), advocates a unique approach, specializing in coexistence and habitat restoration. He warns that fragmentation inevitably results in conflict between humans and orangutans as the nice apes are forced to enter community-managed areas in quest of food.
Instead of moving animals, Wanda suggests creating habitat corridors. This might be achieved by encouraging local communities to grow crops that support each human economic needs and the ecological requirements of orangutans. “For example, communities may very well be encouraged to plant benzoin trees (Styrax sp)” – he proposed. “Humans can collect the useful resin from the trunk, while orangutans can eat the leaves. This creates a win-win scenario that supports coexistence.”
He says this approach respects local livelihoods while ensuring the ecological connectivity crucial for orangutans to survive. Ultimately, the long run of this newfound population hangs within the balance, requiring rapid, progressive and collaborative conservation efforts to stop the entire disappearance of their fragile latest home.
