Conservationists have declared a red alert after four days of catastrophic rainfall killed an estimated 7% of the world’s remaining Tapanuli orangutans. The critically endangered species, found only in the Batang Toru forest of North Sumatra, has seen its population fall from fewer than 800 individuals to an estimated 744 as a result of flash floods and landslides that swept through their habitat between 11 and 14 February.
The disaster was confirmed by affiliates of the Sumatran Orangutan Conservation Programme, a UK-funded initiative supported by the British government’s Darwin Initiative. In a statement released on Wednesday, the programme said that field teams had recovered the bodies of 56 orangutans, including infants and breeding females, with several more reported missing and presumed dead.
“This is an unprecedented event in the history of orangutan conservation,” said Dr. Helen Morley, the programme’s lead veterinarian. “We have never recorded a weather-related die-off on this scale. The species is now one step closer to extinction.”
The Tapanuli orangutan (Pongo tapanuliensis) was recognised as a distinct species in 2017. Its entire global population resides within a fragmented tract of lowland and hill forest on the island of Sumatra. The recent downpour, described by local meteorologists as a once-in-a-century event, triggered landslides that destroyed large sections of the forest canopy and sent torrents of mud through the orangutans’ primary feeding and nesting areas.
UK officials said they were monitoring the situation closely. The Foreign, Commonwealth and Development Office confirmed that emergency funding had been released to support search and rescue operations and to assess the long-term viability of the remaining population. “We are deeply concerned by this devastating loss,” a spokesperson said. “The UK remains committed to protecting global biodiversity and will work with our partners on the ground to stabilise the situation.”
The red alert status means that the conservation programme will now prioritise the relocation of surviving orangutans from the most vulnerable parts of the forest to higher ground, where possible. However, experts cautioned that the available safe habitat is limited, and that long-term survival of the species may hinge on a major reforestation initiative.
“The loss of 56 individuals from such a small population is a catastrophic blow,” said Professor Adrian Walters, a primatologist at the University of Oxford. “If further extreme weather events occur, the species may not recover. This is not simply a conservation problem. It is a geopolitical crisis that demands an urgent international response.”
Climate scientists have warned that the rainfall event is consistent with modelling predictions for the region under climate change. Indonesia has experienced a marked increase in the frequency and intensity of storms in recent decades, and the Batang Toru ecosystem — already under pressure from illegal logging and a proposed hydroelectric dam — is especially vulnerable.
The British government has said it will convene a meeting of donor nations within the next two weeks to coordinate an emergency response. Options under consideration include the creation of an emergency captive breeding programme and the establishment of a forest corridor to link isolated pockets of surviving orangutan habitat.
For now, conservation teams remain on the ground, racing to locate survivors and secure the bodies of the dead for analysis. The hope is that the tragedy will catalyse a shift in policy before the Tapanuli orangutan follows its close cousin, the Sumatran orangutan, toward functional extinction in the wild.
