Cambodia welcomes a bumper crop of critically endangered crocs

Cheering news out of Cambodia has revealed a relative bumper crop of one of the most endangered crocodilians in the world.

Last week, the Wildlife Conservation Society announced that a patrol conducted by its Crocodile Nest Protection Team in cooperation with government officials documented 15 Siamese crocodile hatchlings – each some 30 centimetres long – in a lake in Koh Kong Province’s Sre Ambel district.

Fifteen Siamese crocodile hatchlings were recently documented in a lake in Koh Kong Province sparking hope for the species. Image © WCS

It’s an encouraging report, given the sketchy status of the Siamese croc. Designated as “Critically Endangered” on the IUCN Red List, the reptile exists in perilously low numbers and highly fragmented populations representing the remnants of a once-widespread range in Southeast Asia and Indonesia. Habitat loss, overhunting, and the collection of eggs and hatchlings for crocodile farming decimated the species in the 20th century. The Siamese croc was feared extinct in the wild until 2000, when a team with Fauna and Flora International (FFI) discovered a few small populations in the Cardamom Mountains of southwestern Cambodia: a wild highland that’s among the country’s great refuges of biodiversity, and where the indigenous Pearic culture venerates the crocodile as a manifestation of ancestors.

These couple of decades later, the Cardamoms still harbour the largest recorded populations of Siamese crocodiles in Cambodia, including those in the Veal Veng Marsh, the Areng River, and the Sre Ambel (Kampong Saom) drainage. Cambodia is thought to claim the most Siamese crocs overall, 150 or fewer adults, though Laos may have comparable numbers; the species also persists in Borneo’s East Kalimantan Province, Thailand, and Vietnam (though WCS calls it “almost extinct” in the latter two countries).

Habitat loss, overhunting, and the collection of eggs and hatchlings for crocodile farming has decimated Siamese crocodile numbers in the 20th century. Image © WCS

Siamese crocs – distinguished by a fairly broad snout, a bony ridge behind the eye, and a mild disposition – are mid-sized crocodilians, typically maxing out at three or three and half metres long. Hybrids between Siamese and estuarine crocodiles, however, can reach significantly greater proportions; just such a crossbred saurian, “Yai,” held at a crocodile farm/zoo in Thailand, is, at some six metres, often said to be the largest croc in captivity. Much remains to be ironed out about this much-dwindled and rather mysterious croc’s ecology, though it’s believed to be a generalist predator of fish and other small critters, and fond of sluggish flows, floodplain lakes, and swamps.

Given the continued demand for crocodile hides and ongoing habitat alteration – including hydroelectric development of many of the Cambodian rivers crocs rely on – the future remains decidedly uncertain for the Siamese crocodile. Along with monitoring and protection of nesting crocs involving government officials, groups such as FFI and WCS, and local people, conservation of the species in Cambodia includes captive-breeding programs and releases into the wild of hand-reared juveniles and other animals acquired from captivity. This past June, a female crocodile given to the Phnom Tamao Wildlife Rescue Center in 2017 and returned to the wild the next year managed to nest in the Cardamom Mountains, though her clutch was not fertilised.

One challenge in attempting to release animals acquired from captivity is the widespread hybridisation of Siamese crocodiles with other species such as estuarine and Cuban crocs on crocodile farms, a practice thought to produce more marketable leather. The Royal Zoological Society of Scotland’s WildGenes project – conducted in collaboration with FFI and Cambodia’s Royal University of Phnom Penh – has lately facilitated genetic testing to ensure only pure Siamese crocs are returned to the wild.