Believed to be extinct since the 1930s, the venomous Bangka slow loris has been rediscovered on an Indonesian tropical island. Scientists report that an animal rescue center on Bangka Island encountered more than 90 individuals in recent years, proving the nocturnal primate has survived despite severe habitat loss.
Bangka Slow Loris Rediscovered After Century
The Bangka slow loris, scientifically known as Nycticebus bancanus, is a small, tree-dwelling primate native to Bangka Island, located off the southeastern coast of Sumatra.
Long feared extinct after the last scientific documentation occurred in the 1930s, the species has now stepped back into the scientific spotlight. According to researchers publishing in the journal Spixiana, an animal rescue organization on the island handled more than 90 individuals between 2015 and 2025.
Timon Glaw is a graduate student in conservation and biodiversity management at the Haus des Meeres Aqua Terra zoo and aquarium in Vienna, Austria. He is one of the study’s authors.
Glaw noted that the animals came from various parts of Bangka. This distribution indicates that the population has managed to endure across multiple pockets of the island despite decades of scientific neglect and widespread environmental destruction.
What amazes me in particular is that such a striking primate with unique characteristics received so little scientific attention for almost a hundred years. Its rediscovery also raises hope that other species considered possibly extinct are still surviving in places where scientists have not looked for decades. After all, Bangka Island is only about an hour’s flight from Jakarta, one of the world’s largest cities.
Timon Glaw, conservation and biodiversity management student at Haus des Meeres Aqua Terra and study author
Venomous Defenses of Primate
As a slow loris, Nycticebus bancanus possesses a rare defense mechanism shared by very few mammals on Earth.
These primates produce secretions from specialized glands near their elbows. When threatened, they lift their arms, lick the glands to mix the secretion with their saliva, and deliver the toxic compound via a bite.
Glaw explained that the venom can trigger severe allergic reactions in humans. These reactions are potentially life-threatening.
The venom serves in the wild primarily during conflicts with other slow lorises, or as protection against predators and parasites.
Evolutionarily, the Bangka slow loris is closer to the lemurs of Madagascar and the galagos of Africa than to monkeys, apes, or humans. Its physical traits include a reddish-brown coat, distinct facial markings, large eyes, and a specialized dental comb used for grooming, scraping tree bark for resin, and administering venom. Beneath its primary tongue lies a second specialized tongue designed specifically to clean that dental comb. While its exact diet remains less understood than other slow loris species, researchers believe it feeds on insects, tree sap, nectar, and other plant matter.
Conservation Threats on Island
Historical records for the species on Bangka previously dated back to the early 1930s—specifically between 1930 and 1932.
By 2020, the International Union for Conservation of Nature (IUCN) classified the Bangka slow loris as critically endangered and feared extinct. The conservation organization Re:wild placed it on its lost primates list.
Between 2015 and 2025, the Indonesian wildlife organization Alobi Wildlife Rescue Center recorded more than 90 individual slow lorises rescued from houses, gardens, plantations, and roadsides across the island. Many suffered severe injuries from contact with electrical wires, and some died despite veterinary intervention. Following rehabilitation, 86 of the animals were successfully returned to suitable natural habitats.
Glaw emphasized that the primary threat to the primates is the ongoing destruction of natural forests driven by tin mining and the expansion of oil palm plantations. Protecting the remaining forest tracts and conducting systematic field surveys remain the most urgent priorities to determine exact population sizes and survival zones.
