Successful rewilding Siamese Crocodiles in Bau Sau Ramsar Site, Cat Tien National Park

Cat Tien National Park
Published: 17 January 2023
Last edited: 17 January 2023
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Located in the northwest of Cat Tien National Park, Bau Sau and surrounding wetlands, supported a large population of Siamese Crocodiles before 1980. However, since park was established in 1992, no crocodiles were recorded here. In addition, the natural habitats were heavily disturbed by encroachment for arable lands, exploitation of forest products, hunting and trapping animals, illegal fishing, etc.

The efforts for re-establishing a crocodile population in this area started in late 1990s. From 2001 to 2005, first 60 crocodiles were released into Bau Sau. In September 2005, the first baby crocodiles were recorded. To date, the Siamese Crocodile population in Bau Sau has developed stably with new juveniles recorded regularly over the years.

Together with Siamese Crocodiles, populations of other species using the Bau Sau area such as Gaur, Sambar, Green Peafowl and large water birds are also increasing steadily within the park.


Southeast Asia
Scale of implementation
Freshwater ecosystems
Pool, lake, pond
Wetland (swamp, marsh, peatland)
Local actors
Science and research
Species management
Species Conservation and One Health Interventions
Genetic Conservation
Species Monitoring and Research
Species Conservation Translocations
Species Conservation Planning
Lack of alternative income opportunities


Cat Tien National Park, Dong Nai province, Vietnam
Bau Sau Wetlands and Seasonal Floodplain Ramsar Site


Siamese Crocodile was locally extinct in all Southern Vietnam.

Severe human pressures on the protected areas causing the degradation of habitat quality.

No example of success species reintroduction in Vietnam before this effort was initiated due to the lack of safe and suitable habitats.

Species reintroduction often requires huge financial resources and time-consuming.


Species using the Bau Sau area

Cat Tien National Park

Park visitors

Vietnam Conservation Agencies


Local communities

How do the building blocks interact?

Since the late 1990s, the idea and efforts to set up a programme for re-establishing Siamese Crocodile populations in Cat Tien National Park were initiated. To implement this programme, many necessary factors had to be prepared, especially the readiness of habitat and prey for the reintroduced populations to become established. Before the establishment of the National Park, the wetlands in the park were an important source of livelihood for the local people living in the area. Therefore, two streams of work need to be done at the same time to i) ensure that the reintroduction of the species population is carried out according to scientific and conservation standards and procedures in accordance with international guidelines and ii) ensure that the released populations have a suitable and safe environment to thrive in, avoiding the risk of potential human-wildlife conflict.


  • Successfully re-establishing populations of Siamese Crocodile, which have been locally extinct in the Southern Vietnam since the late 1980s.
  • Populations of other species of conservation concerns such as Gaur, Deer, Green Peafolw, etc. are also better preserved and have more development opportunities.
  • Local awareness is improved, the lives of local people are stabilized, reducing dependence on the park's natural resources.
  • The park’s conservation management work has been improved, with long-term and short-term plans, with supporting tools and equipment, reducing the workload of staff and enhancing management effectiveness.
  • Bau Sau was restored to ensure that the functions of the wetland ecosystem are well maintained, including water storage and regulation, provision of good habitats for aquatic species whose life cycles depend on the water and wetland ecosystem of Dong Nai River basin.


Cat Tien National Park

Dr. Pham Huu Khanh, Head of Science and International Cooperation has worked at Nam Cat Tien Forbidden Forest since 1987. At the time, the fledgling protected area was under severe pressures from encroachment on forest lands for farming; illegal logging; hunting and trapping of wild animals; and fishing with destructive methods etc. Wetlands in the northwest of the park were the most destroyed, where once large mammals and birds in the dry season were congregated, an abundance of freshwater fishes, and the home of Siamese Crocodiles. In addition, the invasion of Mimosa pigra, also contribute to the degradation of the quality of wetland habitats, leading to a decline in numbers of most species.

Before 1980, soldiers of the 600th Division described: "eyes of the crocodiles in Bau Sau at night is as dense as the stars in the sky". However, due to habitat loss and disturbance, and especially uncontrolled hunting of adult individuals for skin, meat and juveniles for farming, Siamese Crocodile populations of Cat Tien and of the whole Southeast region were severely reduced and locally extinct in the early years of the 1990s.

From 1998, with the support of central ministries, provinces and international organizations Cat Tien National Park has made many efforts to improve biodiversity conservation in the park. Especially, Cat Tien Conservation project in the core zones funded by the Dutch Government, and the buffer zone development project co-financed by the Dutch Government, the Government of Vietnam and the World Bank, that helped enhancing forest protection, biodiversity conservation, improving livelihoods of local people leaving in and around the park.

The reintroduction of Siamese Crocodile was started in the late 1990s. From 2001 to 2005, the park released a total of 60 adult crocodiles into Bau Sau. In September 2005, the first baby crocodiles were recorded. As of 2019, monitoring data has recorded at least 286 individuals (including 228 juveniles). Over the past 20 years, the crocodile population here has steadily grown, with new juveniles recorded regularly.

Now, every time visiting Bau Sau, Dr. Khanh always feel very happy and proud of the efforts of many generations of National Park staff, including myself, the support of the government and donors, so far has yielded clear results. In the future, generations of descendants will continue to admire the lord of the swamp basking in the sun and catching prey every time they visit Cat Tien National Park.

Contributed by

tu.nguyenduc_38592's picture

Nguyen Duc Tu IUCN Vietnam

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Cat Tien National Park