A single year of extreme weather in Indonesia wiped out 7% of the world's rarest great apes. The Tapanuli orangutan, already critically endangered, lost dozens of its members to landslides triggered by relentless rainfall in 2025.
A species pushed closer to the edge
The Tapanuli orangutan lives only in the Batang Toru ecosystem on the island of Sumatra, Indonesia. Scientists had estimated fewer than 800 individuals remained before last year. New research shows that landslides in 2025 killed at least 56 of them. That is roughly 7% of the total population. For a species with such a small number, losing that many in one year is a severe blow.
What the study found
Researchers from Indonesian universities and conservation groups analyzed satellite imagery and field reports after an unusually wet rainy season. They linked the deaths directly to landslides that swept through forested areas where the orangutans live. The study did not blame logging or mining for these particular deaths. Instead, it pointed to the intensity of the rainfall itself. The downpours were so heavy that hillsides gave way, burying sections of habitat.
Local communities in North Sumatra also felt the impact. Several villages reported damage to crops and roads from the same landslides. For people who live near the forest, the orangutan holds cultural and ecological importance. Many residents rely on the same watersheds and slopes that collapsed.
A fragile future
The Tapanuli orangutan was only identified as a distinct species in 2017. Its habitat is already fragmented by a hydroelectric dam and agricultural expansion. Now extreme weather has emerged as a direct killer. Scientists say the rainfall patterns that caused the landslides are consistent with broader shifts in the global climate. The study adds a stark data point to the growing evidence that climate change is not a distant threat but a present one for endangered species.
Without intervention, another wet year could push the Tapanuli orangutan even closer to extinction. Conservationists are calling for better monitoring of landslide risks and for emergency response plans that include both people and wildlife. The fate of this great ape now depends on how quickly the world acts to stabilize the climate and protect the last scraps of its home.
