Fires have burned for months across Indonesian Borneo, in a dry season sharpened by a strong El Niño. Primate specialists at the IUCN say the fires are burning in forests that hold more than half of all Bornean orangutans. Dozens have been pulled out alive. How many have not is still unknown.
A dry season that did not end
Borneo's dry season normally peaks between July and September. In 2026 it arrived with an El Niño that forecasters expect to be one of the strongest in about four decades of records, and the fires that follow every dry season spread much further than usual.
The official count, covering January to July, is just over 202,000 hectares burned, and it has not been updated since. The satellite monitoring project Nusantara Atlas estimated that nearly 896,000 hectares had burned by the end of August.
How much of the orangutan's home
In September the primate specialist group of the IUCN, the body that keeps the Red List, warned that fires were burning in habitat holding 52% of Borneo's orangutans. Reporting by Mongabay adds that the fires reach forests containing 13 of the 20 largest remaining populations, and habitat holding 70% of one of the three subspecies, the Central Bornean orangutan.
The monitoring group Geopix counted 17,865 fire hotspots inside mapped orangutan habitat in Kalimantan between 1 June and 28 August. That was 78.5% of every hotspot it recorded in Kalimantan in that period.
One caution about a number travelling on social media. A claim that 60% of orangutan habitat has burned in four months is being shared widely. We could not find a source for it. The figures above describe forests where fires are burning and where orangutans live. They do not say that this share of the forest has been destroyed. As Mongabay reported in early October, the number of orangutans affected by the 2026 fires is not yet known.
Why forests that used to resist fire now burn
Much of lowland Borneo is peat swamp, forest standing on deep, waterlogged soil that does not burn easily while it stays wet. Canals dug to drain it for plantations and timber lower the water table, and dry peat burns for weeks.
The IUCN group lists drainage, deforestation, plantation expansion, small-scale mining and the use of fire to clear farmland among the causes. Fires have now been reported inside every protected area in Kalimantan's lowlands, including Tanjung Puting and Gunung Palung national parks.
Novita and Sempurna
In late September rescuers from the Borneo Orangutan Survival Foundation found a young female, three or four years old, clinging to a tree near Sebangau National Park with burns on all four hands and feet. They named her Novita. She was given oxygen and fluids and taken to the Nyaru Menteng rehabilitation centre, where officials said her burns were improving, though she may not recover fully.
Others were found too late. An adult male named Sempurna was discovered weakened in a dry ditch in an oil palm plantation in West Kalimantan and died on 30 August. The examination pointed to oxygen deprivation from smoke.
By 22 September Indonesia's Ministry of Forestry had recorded 100 wild animals rescued from the fires, 53 of them Bornean orangutans.
Why every animal counts
A female orangutan gives birth roughly once every six to eight years and may raise only three or four young in her life. A population cannot quickly replace the adults it loses.
About 104,000 orangutans remain on Borneo and Sumatra, according to WWF, down from more than 230,000 a century ago. During the El Niño fires of 1997 and 1998, researchers estimated that thousands died. The IUCN group has warned that thousands more could be killed, injured or displaced this time without urgent action.
What is working
Since August the government has deployed 64 aircraft and more than 54,000 people. The fires are expected to last until the rains return in late October or November.
The clearest result comes from the ground. The Borneo Nature Foundation has supported community fire patrols since 2016: nine groups, 138 members, on patrol 16 days a month. In villages without such patrols, the total area burned was five times larger. The IUCN group is also calling for drained peatland to be rewetted, because land that has burned once is many times more likely to burn again.
_Photo: a wild orangutan in Tanjung Puting National Park, Central Kalimantan, August 2018. Jorge Franganillo, CC BY 2.0, via Wikimedia Commons._
_Sources: Hans Nicholas Jong, Mongabay, 23 September and 5 October 2026. Agence France-Presse, 9 October 2026. Figures are attributed in the text to the IUCN SSC Primate Specialist Group, Nusantara Atlas, Geopix, Indonesia's Ministry of Forestry and WWF._