Four days of extreme rain in Indonesia killed 7% of world’s rarest great apes, study finds

The Tapanuli orangutans’ primary habitat is in Batang Toru, North Sumatra, where the ecosystem is threatened by mining, palm oil plantations and a hydropower project. Photograph: Nature Picture Library/Alamy

Extreme rainfall and landslides fuelled by the climate crisis killed 7% of the remaining population of the world’s rarest great ape, a study has found, prompting fears for the species’ survival.

The research suggests 58 out of the remaining 800 critically endangered Tapanuli orangutans (Pongo tapanuliensis) were killed after more than 1,000mm (39in) of rain fell over four days in Indonesia’s North Sumatra province in November 2025. This equates to 11% of the local population and 7% of the entire species.