Saving Siamese Crocodiles
Siamese crocodiles (Crocodylus siamensis) are charismatic, ecologically significant and culturally important. Yet they also struggle in the wild, surviving only in scattered and seriously threatened populations. Chester Zoo is supporting a multi-partner bid to boost the population of these impressive apex predators.
The Siamese crocodile story
More than a third of all surviving crocodilians in the world are endangered. Among them are Siamese crocodiles, a mid-sized, freshwater crocodile that once lived across Southeast Asia. Despite being seen as sacred by some cultures – their images adorn temples and indigenous people have protected them for generations – wild Siamese crocodiles are in serious threat of extinction.
Siamese crocodiles (Crocoylus siamensis) are native to Cambodia, Laos, Thailand and Vietnam. Their range has drastically shrunk over the last century, with many local populations being declared as extinct as thousands of crocodiles were hunted and killed for the international skin trade.
Habitat loss, poaching, hybridisation in crocodile farms and conflict with the fishing industry further depleted the species. These fascinating reptiles are now listed as Critically Endangered on the International Union for Conservation of Nature Red List. Recent estimates suggest as few as only 1,000 pure-bred Siamese crocodiles remain in the wild, though actual numbers could be as low as 250.
The surviving crocodiles live in small and isolated populations, making it difficult for the species to bounce back from the brink without concerted conservation efforts.
Crocodiles in Cambodia
Cambodia hosts several key habitats for Siamese crocodiles surviving in the wild. Siamese crocodiles were declared locally extinct in Cambodia in 1992, but a small population was found during an expedition carried out by our partners Fauna & Flora with the support of the Cambodia Forestry Administration in the early 2000s.
We now know there are small populations surviving in Areng Valley, Chay Reap, Stung Dach, Stung Kiew and Veal Veng which together likely comprise of only 150 around adults.
In the years that followed their rediscovery, Fauna & Fauna set up a breeding programme to boost the number of Siamese crocodiles in Cambodia. One of their facilities is pictured here.
They have successfully released more than 120 Siamese crocodiles into the wild, beginning to repopulate 18 sites across Cambodia.
Collaboration
Chester Zoo has supported Fauna & Flora since 2022, offering technical assistance on the breeding programme. Chester Zoo’s advisors were able to help the team at Phnom Tamao breeding centre improve the hatching and survival rates of hatchlings, further improving the species’ chances of reaching viable numbers.
Now the project is entering a new phase with an aim to concertedly increase the adult population in the wild to at least 300 individuals. This is in line with the Cambodian national strategy for protecting Siamese crocodiles and increasing their national numbers to at least 10,000 individuals.
We have committed to keep improving hatching and survival rates at the breeding centre, to work with local communities to gain public support for Siamese crocodiles and the recovery programme, to improve legal protection for the species, to identify and improve wild habitats ready for the release of Siamese crocodiles and to undertake a new survey of wild individuals to build an up-to-date picture of the species.
The future
Moving forward, Chester Zoo is supporting the team at Phnom Tamao breeding centre to further improve breeding success, assessing everything from diet, nesting, egg incubation and providing juvenile crocs with enrichment and suitable food.
The breeding centre should be able to produce at least 500 healthy and pure-bred adults over the course of the next five years in order to meet the required numbers for wild reintroductions.
The new phase also involves ramping up the involvement of the local community in protecting Siamese crocodile populations and their habitats from poaching and destruction, especially of nesting sites.
More widely, we will support Cambodian conservationists in influencing policies to enable reintroduction in new sites in Cambodia and also strengthen protection of the species across all sites.
