Flying snake and viper among new, rare species discovered in cave in Cambodia

Researchers have discovered multiple new and rare species in previously unexplored caves in Cambodia, including a flying snake and a fluorescent turquoise viper.

Those creatures were found during a multi-year biodiversity study that examined more than 60 limestone caves in Battambang province, western Cambodia. The project took researchers to 10 different hills in the region known for their karsts, which are limestone cliffs filled with caves and hidden ecosystems, according to a report by Fauna & Flora Cambodia, an organization that led the study alongside the country’s Ministry of Environment.

Cambodia’s karst formations have historically been some of the least studied of their kind, the organization said. He described karsts as “small islands of habitat, each with its own collection of plants and animals”, that became isolated from each other over time, as human activity sprang up around them.

“Surrounded by a sea of ​​inhospitable man-made landscapes, many of these creatures are, in fact, trapped,” Fauna & Flora said. “Today, each of those miniature karst paradises contains species found nowhere else in the world.”

From November 2023 to July 2025, teams of experts ventured into the caves through narrow gaps in the limestone, making their way through dark tunnels that were often only large enough for them to crawl on their hands and knees. Photos and videos show explorers picking their way through jagged crevices deep in the karsts, using flashlights to guide them along an otherwise pitch-black maze of rock burrows. In some images, bats fly just above.

New and familiar species.

Beyond the network of confined spaces was a series of pristine caves, where researchers discovered numerous rare species as well as others never before seen. In addition to the viper, they found what the report called “cryptically camouflaged leaf-toed geckos” and brightly colored millipedes, which are probably quite poisonous.

The viper is still being formally characterized, but the report calls it a “spectacular new species” with recognizable triangular heads, which are “highly venomous” and “track their warm-blooded prey using the heat-sensitive nostrils behind their nostrils.”

“Each of these isolated karst areas acts as its own little laboratory, where nature independently performs the same experiment over and over again,” Lee Grismer, a biology professor at California’s La Sierra University who worked on the biodiversity study, said in a statement. Grismer said the result of such quarantine conditions is the development of species that only exist there, sometimes within a single cave.

A variety of other species, some rare and some not, were also recorded within the caves.

The researchers found many reptiles, including a reticulated python, the world’s longest snake, and a bright green flying snake. Also known as the ornate flying snake or golden tree snake, it is native to South and Southeast Asia.

They also found spotted-legged tree frogs and colorful agamid lizards, which are commonly seen throughout the area, according to the report.

Conservation mission

In addition to learning more about the mysterious ecosystems of karsts, the biodiversity study aimed to advocate for their conservation. The ecosystems are among the least protected in the world, Fauna & Flora said. The organization noted that karst habitats “are threatened by poorly planned cement extraction, unmanaged tourism, forest fires, logging and hunting”, and only 1% is legally protected worldwide.

“Every time one of these hills is destroyed, species could be at risk of extinction,” Sothearen Thi, a biodiversity coordinator who also worked on the study, said in a statement. “Many species may disappear before they can be discovered.”