DNA tests find "extinct" Siamese crocodile

Join Our Community of Science Lovers!

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


For nearly 20 years, the critically endangered Siamese crocodile (Crocodylus siamensis) has been considered nearly extinct in the wild, victimized by habitat loss and poaching. A small population was found in Cambodia in 2000 and, until now, it was believed that, at most, 250 of the rare crocodiles existed in the world.

But recently, conservationists became aware of a new population of Siamese crocodiles, all of which were already living in captivity at Cambodia's Phnom Tamao Wildlife Rescue Center. According to researchers from Fauna & Flora International (FFI), this means there is hope of creating a captive-breeding program to save the Siamese crocodile from extinction.

The newly discovered crocs were originally suspected to be hybrids of multiple crocodile species. But conservationists managed to wrestle all 69 crocs living at the center (not an enviable job) to obtain DNA samples. Testing proved that 35 of the 69 animals were purebred Siamese, including six adults and 29 juveniles and hatchlings.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


"This could provide a critical lifeline for the long-term preservation of this critically endangered species," Phnom Tamao Director Nhek Ratanapech said in a prepared statement.

"For the first time in Cambodia, we have a captive population of animals that we know 100 percent are purebred Siamese crocodiles," Adam Starr, who manages the Cambodian Crocodile Conservation Program, told the Associated Press. The program is a joint effort of the Cambodian government and FFI.

FFI and other conservation groups will now help the staff at Phnom Tamao to come up with a breeding program that could yield new crocodiles as early as next year. If successful, they will also work with the IUCN Reintroduction Specialist Group to release Siamese crocodiles back into the wild once the offspring have reached two years of age.

Siamese crocodiles were hunted into near-extinction in the mid–20th century due to their highly prized skin, which is much softer than that of other crocodile species. Researchers knew that some hybrid crocs on Cambodian farms had Siamese DNA because they had long ago been crossbred with other crocodile species to produce larger, faster-growing, softer-skinned animals for commercial exploitation. This is the first time that purebred Siamese crocodiles have been found among any hybrids anywhere in Cambodia.

Image: Siamese crocodile (Crocodylus siamensis). Photo courtesy Photo8.com

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe