Siamese Crocodile Research and Conservation

To study the natural history and promote the survival of Siamese crocodiles in Indonesia, Vietnam and Laos


The Siamese crocodile (Crocodylus siamensis) is one of the most threatened crocodile species worldwide. Historically, the Siamese crocodile occurred over much of mainland Southeast Asia as well as parts of Indonesia. Its current distribution is greatly diminished and fragmented. Extant populations are in Cambodia, Indonesia, Lao PDR and Thailand; wild populations in Vietnam are possibly extirpated.


Therefore, the Siamese crocodile is listed as Critically Endangered on the IUCN Red List, and in Appendix I of CITES. Its natural history is only poorly known. However, scientific knowledge is essential as a basis for sustainable, long-term conservation. Not only is the preservation of the few remaining wild populations of importance, but also the restocking of too small populations or the establishment of reintroduced populations. However, restocking or reintroduction measures conforming to IUCN guidelines require thorough planning (including genetic screening of the founder population), sound habitat selection and continuous, properly documented monitoring.


In the first project phase, we focused on the only known Indonesian population of the Siamese crocodile in Danau Mesangat, a freshwater swamp habitat in the Mahakam River region in eastern Kalimantan. By means of student theses conservation-based natural history research was implemented, also for another sympatrically occurring crocodile species, the Malayan gharial (Tomistoma schlegelii); this species represents another equally important key crocodile species of the Mesangat peat swamps. In a second project phase, a reintroduced, purebred population of the Siamese crocodile was accordingly studied in Cat Tien National Park in southern Vietnam in terms of ecology, behaviour and population status as well as dynamics.


In the current project phase, we focus on an until recently overlooked Siamese crocodile population in Khammouane Province, Lao PDR, which represented at the same time the rediscovery of the species from this province. The goal of the project is to ensure sustainable, community-based conservation of the habitat, the Siamese crocodile and further sympatrically occurring, endangered species.  


WAZA Conservation Project 10007 was implemented in Indonesia by Yayasan Ulin (Ironwood Foundation), with support provided by Cologne Zoo, Dortmund Zoo, Protivin Crocodile Zoo, University of Bonn, University of Cologne and IUCN SSC Crocodile Specialist Group; the project subsequently was pursued in Vietnam and currently is run in Laos by Cologne Zoo together with the Institute of Ecology and Biological Resources, Hanoi, Vietnam Forestry University, Hanoi, Natural Resources and Environment Department, Khammouane, and National University of Lao PDR, Vientiane.




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  • Siamese Crocodile Conservation

    Siamese Crocodile Conservation

    (1) - (2) © Ralf Sommerlad, (3) - (4) © Thomas Ziegler