How one devastating cyclone wiped out 7% of the planet’s rarest great apes

How One Devastating Cyclone Shattered 7% of the Planet’s Rarest Great Apes

How one devastating cyclone wiped out 7 – A new study published this month in the journal *Current Biology* has uncovered a grim reality: a single, intense cyclone triggered catastrophic damage to the survival of the world’s rarest great apes. Cyclone Senyar, which struck the Indonesian island of Sumatra in late November 2025, caused widespread devastation, leading to the loss of over 7% of the global population of Tapanuli orangutans. This species, already teetering on the brink of extinction, now faces an even graver threat from the combined forces of climate change and habitat destruction.

The Scale of the Disaster

The cyclone, one of the most severe in recent years, unleashed more than 16 inches of rainfall across Indonesia, according to the Tsunami and Disaster Mitigation Research Center. This deluge, amplified by climate change, increased the storm’s rainfall intensity by 9% to 50%, depending on the analysis. The resulting floods and landslides obliterated nearly 12% of forest cover in the West Block of the Batang Toru ecosystem, a critical habitat for the Tapanuli orangutan. Researchers estimated that over 20,000 acres of land were scarred by landslides, leaving visible patches of rock, soil, and debris in their wake.

Scientists report that the cyclone claimed the lives of more than 58 Tapanuli orangutans, representing 11% of the local population and 7% of the species’ total global numbers. However, these figures may not fully capture the extent of the tragedy. The study’s authors noted that their calculations relied on population density estimates, potentially underrepresenting the true toll. Other factors, such as diminished food sources and the destruction of forest canopies, could further exacerbate the situation for surviving individuals.

Climate Change and Habitat Loss: A Deadly Double Whammy

Cyclone Senyar’s impact highlights the growing role of climate change in accelerating environmental crises. The research team attributes the storm’s enhanced intensity to rising global temperatures, which are intensifying extreme weather events. This phenomenon, coupled with ongoing deforestation for roads, agriculture, and industrial expansion, has left the orangutans in a precarious position. The Batang Toru ecosystem, which has already been fragmented by human activity, was particularly vulnerable to the cyclone’s aftermath.

As the ground became saturated, large sections of the hillside collapsed, creating a cascade of destruction. These landslides, often triggered with little warning, trapped orangutans in their paths. “It could well be that up to 120 animals perished during the landslide events,” said Erik Meijaard, lead author of the study and managing director of Borneo Futures in Brunei. He also noted that the actual number could be lower than the 58 estimated, depending on the accuracy of the data used.

The Tapanuli orangutan’s slow recovery rate compounds the risk of extinction. Female individuals typically give birth every six to nine years, making population growth extremely difficult. This reproductive delay means that even a moderate loss of individuals can have long-term consequences for the species’ survival. “The apes live in isolated populations across Sumatra, so any single event can ripple through their entire community,” Meijaard emphasized.

A Call for Urgent Conservation Action

Experts warn that the damage inflicted by Cyclone Senyar may be just the beginning. The study’s findings have spurred demands for stronger conservation policies from the Indonesian government. “Whether these orangutans can rebound depends on the steps taken now,” said Friederike Otto, a climate science professor at Imperial College London, who was not involved in the research. “If we can halt deforestation and reconnect fragmented habitats, the species might still have a fighting chance.” However, she cautioned that another heavy rainfall event, increasingly likely due to climate change, could undermine these efforts.

“If this tragedy serves as a wake-up call to really halt deforestation, reconnect some of the fragmented forest habitats where that is possible, and bring governments, local communities, and industries together to support conservation efforts, the species may still have a chance,” Otto told CNN.

Adriano Lameira, a primatologist from the University of Warwick studying Sumatran orangutans, echoed these concerns. “After decades of conservation efforts, it’s clear the current system isn’t sufficient to safeguard the country’s unique natural resources,” he said. Lameira highlighted the orangutans’ ecological and scientific significance, stating, “These apes are not just a symbol of biodiversity—they offer invaluable insights into the evolutionary history of humans.”

“The Tapanuli orangutan also provides unique insights into the potential lives of ancient human ancestors and why and how humans came to become who we are today,” Lameira added.

The cyclone’s destruction extends beyond the immediate loss of life. The West Block of the Batang Toru ecosystem, already under pressure from land clearing, now faces even greater challenges. With over 1,000 people killed and more than a million displaced, the region’s environmental and social landscapes have been irrevocably altered. The orangutans’ survival hinges on the resilience of their habitat, which is increasingly threatened by both natural and human-induced factors.

Researchers stress that the damage may worsen if the orangutans’ breeding success declines post-disaster. The species’ low reproductive rate and isolated populations mean that even small increases in mortality can tip the balance toward extinction. Meijaard described the current situation as a “path toward extinction,” citing annual losses of over 1% and the compounding effect of such events. “This is a species that can’t afford to lose more than it already has,” he said.

As the study underscores, the survival of the Tapanuli orangutan is now inextricably linked to the success of conservation measures. The Indonesian government is urged to implement stricter protections for the apes’ habitat, addressing threats from both human activity and climate-related disasters. Without immediate action, the cyclone’s impact may become a permanent scar on the planet’s biodiversity. The plight of these great apes serves as a stark reminder of the interconnected challenges facing ecosystems worldwide, urging a collective response to safeguard their future.