Even powerful orangutans are helpless against massive landslides
In the forests of Sumatra, a single storm has compressed years of extinction risk into four days, killing roughly 7 percent of the Tapanuli orangutan — a great ape so recently known to science that humanity had barely begun to understand it before being forced to mourn it. Cyclone Senyar, which claimed more than a thousand human lives across Southeast Asia in November 2025, also swept away approximately 58 of fewer than 800 remaining individuals of a species discovered only in 2017. The event is not merely a tragedy of numbers but a warning written in landslide and loss: as climate change intensifies extreme weather across the region, the margin between a species' survival and its disappearance grows ever thinner.
- A single cyclone erased the equivalent of seven years of the Tapanuli orangutan's tolerable annual population loss in just four days, pushing a critically endangered species measurably closer to extinction.
- Researchers found bodies half-buried in mud and debris, with one scientist describing the visceral horror of animals rendered helpless as entire hectares of forest collapsed around them in massive landslides.
- Climate change is not a distant threat here — it directly amplified Cyclone Senyar's intensity, and scientists warn that extreme rainfall events in Sumatra will only grow more frequent and severe.
- Indonesia's temporary pause on mining, oil palm, and hydropower development in the Batang Toru protected forest has opened a rare window for coordinated conservation action before the next crisis arrives.
- Researchers are now calling for sustained international funding, climate-responsive planning, and strengthened domestic protections to prevent what would be the first modern extinction of a great ape species.
In late November 2025, Cyclone Senyar tore through Sumatra with devastating force, killing more than a thousand people across Southeast Asia. In the weeks that followed, a humanitarian worker discovered something that reframed the disaster's full scale: the body of a Tapanuli orangutan, half-buried in mud in a village where the animals had once come to feed. "They used to come to this place to eat fruits," he said. "But now it seems to have become their graveyard."
A new study has since quantified the storm's toll on one of Earth's rarest creatures. Four days of extreme rain and landslides killed approximately 58 Tapanuli orangutans — around 7 percent of a species with fewer than 800 individuals remaining. Discovered only in 2017, the Tapanuli orangutan is among the newest-known primates and already among the most imperiled. Co-author Professor Erik Meijaard, who initially estimated 35 deaths before revising upward, described the physical evidence as harrowing: powerful animals rendered completely helpless as forests collapsed around them in cascading landslides.
What makes the loss so alarming is its trajectory. Scientists have established that the Tapanuli orangutan cannot survive losing more than 1 percent of its population annually. Cyclone Senyar consumed seven years of that threshold in four days. And crucially, researchers say climate change intensified the storm — with extreme rainfall in Sumatra projected to increase in frequency and severity in the years ahead.
One narrow opening exists. Indonesia has temporarily halted major development projects — mining, oil palm, hydropower — in the Batang Toru protected forest, giving conservationists a rare window to assess damage and coordinate a response. The study's authors argue that averting the first modern extinction of a great ape will require international financial and technical support alongside stronger domestic protections. What Sumatra's forests revealed in November was a collision of climate instability, biodiversity loss, and the fragility of a species the world had only just learned to name.
In late November, a cyclone tore across the Indonesian island of Sumatra with such violence that it killed more than a thousand people across Southeast Asia—the deadliest natural disaster the region had seen all year. What happened to the wildlife in the storm's path took longer to understand. Weeks after Cyclone Senyar passed, a humanitarian worker named Deckey Chandra found the body of what appeared to be a Tapanuli orangutan half-buried in mud and debris in Pulo Pakkat village. "I have seen several dead bodies of humans in the past few days but this was the first dead wildlife," Chandra said. "They used to come to this place to eat fruits. But now it seems to have become their graveyard."
A new study published this week quantifies what that storm cost one of Earth's rarest creatures. Four days of extreme rain and landslides killed approximately 58 Tapanuli orangutans—roughly 7 percent of the entire species. There are fewer than 800 of these great apes left in the world. The species was only discovered in 2017, making it one of science's newest-known primates and already one of its most imperiled.
Professor Erik Meijaard, who manages Borneo Futures in Brunei and co-authored the study, had initially estimated the cyclone killed around 35 orangutans. When he saw photographs of one of the dead animals, the reality of the disaster became visceral. "What struck me is that all the flesh had been ripped off the face," he said. "If a few hectares of forest comes down in massive landslides, even powerful orangutans are helpless and just get mangled. It must have been hellish in the forest at the time." His revised estimate of 58 deaths represents a significant increase from that first assessment.
The loss matters not because it is isolated but because it is almost certainly not. Researchers emphasize that while Cyclone Senyar was an unusual event, human-induced climate change played a significant role in its intensity. More troubling still: the frequency and intensity of extreme rainfall in Sumatra is expected to increase in the years ahead. Studies show that the Tapanuli orangutan will face extinction if it continues to lose more than 1 percent of its population each year. A single cyclone has now taken away seven years' worth of that threshold in four days.
There is one narrow opening for intervention. The Indonesian government has temporarily halted major developments in the Batang Toru area, a protected forest in Sumatra where many of these orangutans live. Mining operations, oil palm plantations, and hydropower projects have been paused, giving researchers a rare window to assess the ecological damage and plan a coordinated response. The authors of the study argue that preventing the first modern extinction of a great ape species will require sustained international support—strengthened domestic protection, climate-responsive planning, and global financial and technical assistance working in concert.
What happened in Sumatra in November was a collision of three crises: climate instability, biodiversity loss, and the vulnerability of a species so newly discovered that science is still learning how to save it. The storm revealed how fragile that margin is. The question now is whether the world can act fast enough to widen it.
Citações Notáveis
They used to come to this place to eat fruits. But now it seems to have become their graveyard.— Deckey Chandra, humanitarian worker who discovered a dead orangutan
If a few hectares of forest comes down in massive landslides, even powerful orangutans are helpless and just get mangled.— Professor Erik Meijaard, study co-author
A Conversa do Hearth Outra perspectiva sobre a história
When you say the species was only discovered in 2017, what does that actually mean? They were always there, right?
Yes—they were always there. But they were living in a remote forest in Sumatra that hadn't been thoroughly studied. Scientists thought they were a subspecies of another orangutan. It took genetic analysis to prove they were distinct. So we've known about them as a separate species for less than a decade.
And now 7 percent of them are gone in a single storm. Does that number feel catastrophic to you?
It does. Because the population is so small that every individual matters enormously. Losing 58 animals isn't just a percentage—it's a loss of genetic diversity, breeding potential, and knowledge. These aren't abstract creatures. Some of them were probably mothers, which means orphaned offspring.
The study mentions climate change played a significant role. But cyclones happen naturally. How do we know this one was made worse by climate change?
We can't point to any single storm and say definitively that climate change caused it. But we can say that warming oceans and atmosphere make extreme rainfall events more intense and more frequent. The researchers are saying: this storm happened, and it was devastating. And the pattern going forward—more storms like this—that's what climate change is driving.
So the temporary halt on development in the protected forest—is that actually going to save them?
It buys time. It stops new threats from being added to the ones already there. But it doesn't solve the core problem: the forest itself is becoming a more dangerous place because of the climate. You can protect the land, but you can't protect it from the weather.
What does extinction of a great ape species actually mean for the rest of us?
It means we lose a branch of our own evolutionary tree. It means we failed to protect something we only just learned existed. And practically, it signals that our climate and conservation systems are broken—because if we can't save a species we're actively trying to save, what does that say about everything else we're losing quietly?