New purebred Siamese crocodiles discovered

12/02/2009

The Wildlife Rescue Team rescue a Siamese croc for transport to the Phnom Tamao Wildlife Rescue Center/ Credit Wildlife Alliance

In 1992, scientists declared the Siamese crocodile (Crocodylus siamensis) – which once lived throughout southeast Asia – functionally extinct in the wild. But then in 2000, biologists discovered a small remnant population of a couple dozen animals in southwest Cambodia. With careful protection, the critically endangered reptile has repopulated the small region until today, when they number around 250. But a finding this week brought even more hope to the cause. Scientists at Thailand’s Kasetsart University tested the DNA of 69 crocodiles at the Phnom Tamao Wildlife Rescue Centre outside Phnom Penh, Cambodia just to find out if, by chance, one or two might be a purebred Siamese croc rather than a hybrid species. What luck! The tests revealed 35 of the animals were purebred, and six of them were mature adults, unrelated to one another.

That’s good news for several reasons. Not only does it increase the total population size of these rare animals, but they could potentially be used to enhance the genetic diversity of captive breeding programs, and then ultimately reintroduced in the wild. The more animals exist, the greater the genetic diversity and that is always better for captive breeding programs. Several facilities hold Siamese crocodiles in Thailand and Cambodia, and some have bred them in captivity. Biologists at the Phnom Tamao Rescue Centre had planned to start a program to reintroduce crocs to get the wild population up to 500 indivduals, at which point they are not considered critically endangered. The animals live up to fifteen years, so this is a long-term program, since several of the 35 purebred Siamese crocodiles are still juveniles. However the six adults can start breeding now, and biologists will introduce their offspring into various parts of Cambodia when they reach two years old.

"Unlike any other program to date, we have the potential to re-introduce, monitor and protect, breed in the wild, and multiply within 15 years without disturbance of the actual habitat," says Adam Starr, Program Director for Fauna & Flora International, a nonprofit organization involved in the effort. "Keep in mind, I said potential – things don’t always go according to plan."

Biologists still know virtually nothing about the Siamese croc’s natural history in the wild but they do know that they live in freshwater swamps, slow-moving rivers, and some lakes, and once lived in the countries of Indonesia, Vietnam, Laos , East Malaysia, Thailand, Myanmar, and Brunei. They declined from hunting and habitat degradation. They can grow up to 13 feet, though most don’t grow longer than 9 feet.

The Cambodian-run Phnom Tamao Wildlife Rescue Centre houses over 11,000 animals, many rescued from the pet trade, poachers, and wildlife traffickers. They house 93 species of threatened and endangered species, and reintroduce them into the wild where feasible. The Center sits on over 5,000 acres of regenerating forest. In addition to Fauna & Flora International, the rescue center works with the Wildlife Alliance - which has started a community-based ecotourism program - as well as other wildlife conservation organizations. Of the the men in the photos, Starr says, "They did an outstanding job of working together, handling the animals with the upmost of care, and collecting the DNA. It should be noted that given the amount of planning and hands-on work they have done with these animals, there was a true sense of pride and ownership of the final results from their efforts. They really are the heroes of this project (other than the purebred Siamese crocodiles themselves)."