An extreme multi-day rainfall event in Indonesia in 2025 triggered landslides that significantly affected the largest remaining habitat for a critically endangered orangutan. A new study estimates that approximately 11% of the Tapanuli orangutan (Pongo tapanuliensis) population was lost during the landslide event on the island of Sumatra. Approximately 800 Tapanuli orangutans remain in the world and previous research has demonstrated that population losses exceeding 1% annually will result in extinction. The new research estimates roughly 53 apes died in the recent disasters, but losses could be as high as 120 or as low as 18. Scientists examining the landslide patterns state that the disasters were rapid and highly destructive, leaving any orangutans caught with little chance of escape. At the time of publication, field studies have not been conducted to verify the losses.
