Critically endangered Tapanuli orangutan population falls after heavy rain and landslides, fuelled by climate crisis, in North Sumatra 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.