Key facts
- At least 58 Tapanuli orangutans, 7% of the species' total population of 800, died in recent floods and landslides in Sumatra.
- The disaster was linked to extreme rainfall and landslides, with a study suggesting human-induced climate change intensified the events.
- Approximately 8,300 hectares of the orangutans' key forest habitat were destroyed by landslides.
- Researchers are calling for an immediate moratorium on activities that degrade the remaining orangutans’ habitat and the expansion of protected areas.
- The Indonesian government has temporarily paused major industrial activity in the affected area for investigation.
Floods and landslides in Indonesia's North Sumatra province in November 2025 killed at least 58 Tapanuli orangutans, representing 7% of the critically endangered species' total population of approximately 800 individuals. The disaster was fueled by more than 1,000mm of rain over four days, with a study suggesting human-induced climate change increased rainfall intensity by up to 50%.
The research, published in Current Biology, also found that approximately 8,300 hectares, or 11.7% of the key forest habitat in the Batang Toru ecosystem, were destroyed by landslides. Scientists attribute the severity of the event to climate change, exacerbated by ongoing habitat degradation from mining, palm oil plantations, and a hydropower project.
Researchers are calling for an immediate moratorium on land-use activities that degrade the remaining orangutan habitat and an expansion of protected areas to ensure the species' long-term survival. The Indonesian government has temporarily paused major industrial activity in the Batang Toru area to allow for investigations into securing the orangutan's future.