Alligator sinensis

Common names: Chinese alligator, Yangtse alligator, T’o, Yow Lung Range: China

CITES: Appendix II (Captive bred population)
CSG Action Plan: Availability of Survey Data – Adequate
Need for Wild Population Recovery – Highest
Potential for Sustainable Management – Moderate
1996 IUCN Red List: CR (Critically Endangered). Criteria: A.1.c. A decline of >80% in 3 generations in area of occupancy, area of occupancy >10km² , D1. possibly fewer than 50 wild adults.
Principal threats: Habitat destruction, limited distribution.

Ecology and natural history

The Chinese alligator is a relatively small crocodilian with a maximum length of approximately 2m (Brazaitis 1973). Although it was at one time more widely distributed in China, the Chinese alligator is currently found only in parts of the lower Yangtze (Chang Jiang) River, principally in the provinces of Anhui, Zhejiang, and Jiangsu (Huang 1982, Chen 1990). Because they occur at a comparatively high northern latitude, Chinese alligators spend a large portion of the year hibernating in subterranean burrows (Huang 1982, Watanabe and Huang 1984). The burrows can be quite complex, with above and below-ground pools, and numerous airholes (Chen et al. 1990). The extensive use of these burrows and their very secretive behavior has allowed Chinese alligators to inhabit wetland habitats in areas with dense human populations. The three principal habitat types where this species can currently be found are riverine and swampy areas, low-elevation agricultural communes, and tree farm communes up to 100m above sea level (Watanabe and Huang 1984).

Chinese alligators usually begin to emerge from their dens to bask in May. In June, with warming temperatures, alligators will begin to make nocturnal sorties. Nesting occurs from early July to late August (Huang 1982). Like the American alligator, Chinese alligators make a mound nest of decaying vegetation. Nesting takes places in mid-July, and clutches typically contain 10–40 eggs.

Conservation and status

The Chinese alligator is one of the world’s most endangered crocodilians. Although it was at one time widely distributed throughout the eastern Yangtze River system, the current distribution of the species is restricted to extremely small fragments of its former range in Anhui and Zhejiang Province. The single greatest problem facing the Chinese alligator is habitat destruction related to the intense human population pressures in the region. Very little natural wetland habitat remains, and what does exist contains very few alligators. Most of the remaining populations are located in modified wetlands associated with agricultural or tree-farm communes, where they are vulnerable to human predation. Occupation of surrounding land for agriculture is complete and the destructive effect of alligator burrows on farm dykes causes problems with local people.

New information was produced as a result of a site visit conducted by CSG members in early 1992 and an application of China to register a captive breeding facility (Webb and Vernon 1992). The Chinese alligator has apparently become more restricted in distribution since the surveys by Huang 1982. Chinese alligators are found in the wild in 13 small protected areas (up to 3km² ) within the Anhui Research Center of Chinese Alligator Reproduction (ARCCAR) conservation reserve, and in a small number of localities outside the reserve in Anhui Province. In some cases these are small or remnant populations with little or no breeding known. In several protected areas, the populations are substantial (30–100 individuals) and natural reproduction continues. Personnel of ARCCAR estimate a current wild population of around 800–1,000 individuals. Surveys conducted between 1981 and 1990 suggest a rate of population increase of around 15% per year in protected habitats (Webb and Vernon 1992). A very small remnant population may persist in Anji county of Zhejiang Province (Fu 1994). Alligators are legally protected, and a number of the communes have been classified as alligator preserves, but animals may still be killed or collected for sale to zoos or government-sponsored farms.

Besides the official protected status, the conservation of alligators in China has been based on the development of a number of rearing centers. ARCCAR was established in 1979 and stocked between 1981–82 with 212 individuals collected from the wild. Of these, 160–170 were still alive in 1990. Wild eggs (787 in total) were also collected between 1982 and 1985. Captive breeding has been very successful and the first F₂ were produced in 1988. By 1991 the total stock held was 4,197 alligators with 500–900 new hatchlings produced annually. A much smaller farm at Yinjiaban is operated by the local cooperative and maintains 118 alligators (2:2:114). Additional breeding centers have been established at National Forest Park of Gianaohu (Thousand Island Lake), and Quiongshan, Hainan Island (Zhang 1994a and 1994b.).

In 1992 the ARCCAR facility was registered with CITES as a captive breeding operation and qualified to enter trade with captive bred Chinese alligators. The intentions expressed at the time of registration were to provide alligators for local meat consumption and for the European pet market. Some discussion was also held on utilizing temperature dependent sex determination to provide single sex animals for the market. The current level of trade is not known but income from the export of alligators is needed to support the continuation of captive breeding and conservation. In 1993, management of the farm was leased to a Thai company that intends to operate the farm and has provided a substantial capital injection (Zhang 1993). Additional breeding facilities have been established at Beijing and on Hainan Island with stock from ARCCAR. The future survival of the Chinese alligator in China is now dependent upon continuing economic success of the commercial captive breeding operations (see Watanabe 1983, Webb 1993).

Captive breeding of Chinese alligators has also been accomplished at the Bronx Zoo, the St. Augustine Alligator Farm, and the Rockefeller Refuge in the United States. A studbook is maintained for US captive breeding by the American Zoo and Aquarium Association (AZA). At present there are 209 specimens in zoos outside of China; 147 in 14 US zoos (Behler 1993) and seven in four European zoos (Honegger and Hunt 1990).

Priority projects

High priority

Improve surveys of the status of wild populations: Continued monitoring and quantitative surveying of the known wild populations is needed to ensure that these are maintained at the best possible abundance within the very limited available habitat. The survey should address the current status and distribution of wild populations. An important function of this survey should also be to identify suitable alligator habitat that could be used for reintroduction or restocking programs.

Enhanced protection of wild populations: Many of the surviving alligator populations are located in human made habitats in close association with dense human populations. Efforts are needed through education, to emphasize the protected status of the alligator and enforce the existing protective legislation. Part of this program should include an educational component to increase the awareness among local people of the protected status of Chinese alligators.

Maintain and manage captive populations: Captive populations, both within and outside China, are the current repository of most of the individuals and most of the genetic diversity of this species. These populations should be managed in a manner that ensures maximum genetic diversity and the maintenance of an adequate founder base for the future. To this end the managers of the various captive collections should communicate and cooperate in matters of information and studbook maintenance, exchange of captive specimens and husbandry technology.

Moderate priority

Investigation of the ecology of wild animals: A prerequisite for any conservation action is a good understanding of the ecology of the species involved. Before any active management of wild Chinese alligator populations (such as restocking or reintroduction) is attempted, ecological studies should be initiated. A number of study sites need to be established where regular censusing can be conducted, and a number of basic ecological questions addressed. In particular habitat use, population size structure, sex ratio, and nesting ecology need to be investigated.

Chinese alligator, Alligator sinensis, captive adult female
ID 910261 from the Bronx Zoo. Part of the US captive
breeding program for this species. Photo by B. Shwedick.