The Venomous Primate That Hid From Science for Ninety Years

The Venomous Primate that science gave up on is alive and hiding in plain sight. A new study confirms that the Bangka slow loris — a big-eyed, venomous primate not documented in the scientific literature since the 1930s — still survives on the Indonesian island of Bangka, turning up in backyards, along roadsides and on power lines.

The evidence comes from more than ninety Bangka slow lorises that the Alobi Wildlife Rescue Center rescued between 2015 and 2025, according to the study, published in the scientific journal Spixiana, as reported by Phys.org. The paper makes the loris one of the most dramatic recent entries on Re:wild’s list of most wanted lost primates — species the conservation group is actively trying to relocate.

Lost to Science, Not to the Locals

Although scientists had not documented the species in nearly a century, it was never lost to the people of Bangka. For more than a decade, Alobi has been rescuing slow lorises reported by residents and local authorities across the island, nursing the animals back to health and returning those that recover to protected forest. Until now, those encounters had never made their way into the scientific literature.

The study itself began with a conversation in Java. While visiting a conservation breeding facility there, study co-author Timon Glaw of the Haus des Meeres Aqua Terra Zoo learned from conservationist Jochen Menner that the Bangka slow loris was listed as critically endangered, possibly extinct, on the IUCN Red List — and that it sat on Re:wild’s most wanted list. Menner connected him with Alobi, where Glaw found something the scientific record did not: a decade of documented encounters with the species. The three organizations then teamed up to analyze the records and publish the findings, just in time for Lost Species Month in October.

“The team at Alobi has spent more than a decade quietly rescuing, healing and releasing these animals, and their careful records are what have finally brought this primate back into scientific view,” said Benji Barca, Re:wild’s exploration program manager. “It is another reminder that conservation depends on the knowledge of local communities, Indigenous peoples and others who know these species and landscapes intimately. A species can disappear from the scientific record without disappearing from the lives of the people who share its home.”

The Only Venomous Primate on Earth

Slow lorises are among the strangest primates alive. They are the only primates known to be venomous: they lick a gland on the inside of the upper arm and mix its secretion with saliva, producing a bite that can be painful and cause swelling. They have huge round eyes for seeing in the dark, a comb of specialized lower teeth for grooming, and they move slowly, silently and deliberately through the trees so they blend into the night.

The Bangka slow loris is a small, reddish-backed loris with a pale facial mask. It was first described in 1906 but was only recognized as its own species in 2013 — meaning it spent more than a century hiding inside another species’ identity before vanishing from the record altogether. According to the study, Alobi rescued lorises in all four regencies of Bangka Island and in the city of Pangkal Pinang, suggesting the Venomous Primate may still live across much of the island. Of the rescued animals, eighty-six recovered and were released at seven carefully chosen sites, in the island’s larger forest fragments that still offer good habitat and some level of protection.

Found — and Still in Danger

Rediscovery is not the same as safety. “We are glad to contribute to the scientific record to show that the Bangka slow loris is not lost, but the species is still very close to extinction,” said Langka Sani, director of the Alobi Wildlife Rescue Center. “Its natural habitat on Bangka Island has shrunk significantly because of illegal tin mining and massive land clearing for oil palm plantations. We ask people around the world to support us in saving the Bangka slow loris while we still can.”

The threats stack up. Bangka Island is home to more than one million people, and the study names human settlements, roads and power lines as significant dangers to the species. Slow lorises are also targeted by the pet trade across their Asian range, where their big eyes make them popular — and where traders sometimes clip their teeth to make them safer to handle. A primate that survived a century of scientific neglect now has to survive an island being dug up and cleared around it.

What Comes Next

“Bringing the Bangka slow loris back onto the scientific radar is only the first step,” Glaw said. The team says it urgently needs a long-term conservation strategy built on population surveys, genetic studies and, above all, protection of the species’ remaining habitat. The next challenge, he added, is to make sure it does not actually become extinct.

The study’s authors recommend a conservation program on Bangka that protects suitable habitat and continues monitored releases under international guidelines, plus a conservation breeding program that could help researchers learn more about the species’ biology. Next steps include tracking how the released lorises fare once they are back in the forest.

For anyone watching the lost-species beat, the loris is proof of a bigger pattern: the map of what science knows has blank spots, and the people living inside those blank spots often know exactly what is there. Sometimes saving a species starts not with an expedition, but with answering the phone when a neighbor finds something strange in the backyard.

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