Surprise DNA results boost chances of "extinct" crocodile (Feature)

By Robert Carmichael and Dararoath Vandeth Nov 12, 2009, 8:48 GMT

   Phnom Penh - In 1992, the Siamese crocodile was declared extinct in the wild. It was a depressing end for a creature that was once widespread across its native South-East Asian habitat.

   Just a decade later there was altogether better news when field studies by researchers from the Cambodian government and wildlife organizations found a number of Siamese crocodiles in the wild.

   There are now reckoned to be 250 Siamese crocodiles in the wild, most of which live in the Cardamom Mountains of southern Cambodia.

   This week there was yet more good news. DNA tests released in Phnom Penh showed that 35 crocodiles at a wildlife recovery centre outside the Cambodian capital are purebred Siamese crocodiles. Experts had worried that they would be mixed breeds.

   The news is a boost to the chances of the Siamese crocodile, which is classified as critically endangered on the Red List of the International Union for Conservation of Nature.

   Adam Starr, who manages the Cambodian crocodile conservation programme at Fauna & Flora International, a conservation group, said learning that 35 crocodiles out of 69 tested are purebred was 'really encouraging.'

   'Six of the animals could be used as breeding pairs and 29 young or hatchling crocodiles could be released into the wild,' he said.

   Siamese crocodiles were once were found in Laos, Cambodia, Thailand, Vietnam and Indonesia. They are now extinct in 99 per cent of their original habitat. The crocodiles in just three areas of Cambodia comprise the bulk of the world's wild population.

   'Over the past 100 years as rice paddies became standard through South-East Asia, most of the wetlands [where they lived] were destroyed,' Starr explained. 'The species was virtually eliminated from the landscape except at crocodile farms.'

   Nhek Ratanapech, national coordinator of Cambodia's Crocodile Conservation Programme and director of the Phnom Tamao Wildlife Rescue Centre where the 35 purebred crocodiles currently live, said the DNA results are very good news.

   'This could provide a critical lifeline for the long-term preservation of this critically endangered species,' he said.

   The next step is to establish a breeding programme that over five years will increase the purebred Siamese crocodile population, both captured and wild, to 450. Once the population of mature crocodiles in the wild reaches 500, the animal will move off the critically endangered list.

   'Cambodia is the last shelter of the [Siamese] crocodile in South-East Asia,' he said.

   Nhek Ratanapech explained that under the proposed breeding and release programme, hatchlings would be kept for up to two years before being freed into the wild. That will improve their chances of survival, although risks remain.

   'Inbreeding is a concern as the offspring can be weak or even die if the genetic pool is not varied,' he said.

   Fortunately, the six breeding-stock crocodiles uncovered by the DNA tests are unrelated.

   Starr said the testing showed some young crocodiles are related.

   'But if we were to do more in-depth genetic research we could determine which are brothers and sisters,' he said. 'It's not perfect - I wouldn't say the situation is everything we could hope for, but it's far from bad.'

   Siamese crocodiles take 15 years to reach maturity, so the hatchlings will still face a tough task when they are eventually released. Although poaching has dropped off markedly since the 1980s and '90s, planned hydroelectric dams could interfere with the crocodiles' habitat, and human encroachment remains an issue.

   'It's the first step in trying to secure their future and survival,' said Amy van Nice of Wildlife Alliance, a non-governmental organization that sourced funding for the testing and is involved in the programme at Phnom Tamao. 'They are so critically endangered - everyone and everything has its role and we need to ensure their survival.'

   Starr said the news marked a good first step 'of about 1,000 steps.'

   'We should not be jumping for joy too quickly,' he added.

   There is more to the proposed crocodile programme than biodiversity. Crocodiles are prominent in aspects of Cambodian culture and the country's Buddhist heritage, Starr said.

   'There are bas-reliefs of crocodiles on Angkor Wat temple, and Cambodian culture has stories of crocodiles,' he pointed out. 'Also Buddhist scholars believe crocodiles are defenders of the Buddha.'

   And though they are hardly cuddly, Siamese crocodiles are better-natured than their saltwater or Nile cousins, despite the fact that they can reach more than 3 metres in length and come with ferocious-looking teeth.

   'They're not like saltwater crocodiles - those are massive and very territorial,' Starr said. 'There are no known cases of a Siamese crocodile aggressively attacking a human.'

   There is a bigger picture to consider, too. Starr says crocodiles have been on earth for 300 million years, yet in only a century one species has come perilously close to extinction.

   'For me it's a shame that one species has been all but eradicated for one reason and one reason only - and that's human activity,' he says. 'Siamese crocodiles are just one example, but this holds true across the board for all sorts of species.'