Crocodylus mindorensis

Common name: Philippine crocodile Range: Philippines

CITES: Appendix I
CSG Action Plan: Availability of Survey Data – Adequate
Need for Wild Population Recovery – Highest
Potential for Sustainable Management – Low
1996 IUCN Red List: CR Critically Endangered. Criteria A.1.c, Observed decline in extent of occurence >80% in 3 generations. C.2.a Less than 250 adults in the wild, populations highly fragmented and declining.
Principal threats: Habitat destruction, limited distribution.

Ecology and natural history

The Philippine crocodile is a relatively small, little known freshwater Asian crocodile. Maximum size in males reportedly does not exceed 3m. Until fairly recently the Philippine crocodile was considered to be a subspecies of the New Guinea crocodile (Crocodylus novaeguineae). Ross (1990, 1992) has resurrected the name Crocodylus raninus for a species of lacustrine crocodile similar to C. mindorensis and C. novaeguineae based on four 19th century museum specimens and restricted to Borneo, but the paucity of specimens from that region make its identity and taxonomic status difficult to evaluate. The identity and taxonomy of the freshwater crocodiles of Indo-Malayan region requires further study.

The historical distribution of the Philippine crocodile is Luzon, Mindoro, Masbate, Samar, Jolo, Negros, Busuanga and Mindanao (Ross 1982, Ross and Alcala 1983). The report of a small introduced population on Palau is now known to be in error (Messel and King 1992a). Its preferred habitats include freshwater marshes, the tributaries of large rivers, small lakes and ponds (Ross 1982). Very little else is known about the ecology of wild populations. In captivity females are known to make mound nests and lay 10–20 eggs.

Conservation and status

Conservation and status The Philippine crocodile is one of the most severely threatened species of crocodiles. Initial population decline was associated with commercial overexploitation. Currently, the principal threats are habitat loss and killing by local people. Very high human population density and the people’s intolerance of crocodiles is the major threat. Current re-occupation of agricultural land abandoned during political strife may cause continued depletion. Surveys in 1980–1982 (Ross 1982, Ross and Alcala 1983), reported extremely depleted wild populations, with perhaps no more than 500–1000 individuals remaining. Crocodiles have apparently disappeared from Luzon, Masbate, Samar and Jolo, where they formerly occurred, and no large population exists. The species persist as isolated individuals and small populations in Mindanao, Negros and Mindoro. Confirmed sites include Nabuntaran, Calarian Lake, Macasendy marsh, Liguasan marsh (Mindanao) and the Pagatban river (Negros) (Ortega and Regoniel 1993). C. mindorensis still occurs in the Dipuyai and Busuanga rivers on Busuanga (Regoniel 1993, Ortega, Regoniel and Ross 1994), where they were previously thought extinct. Current wild population size may be no more than 100 non-hatchlings. A small captive propagation program is being conducted by Silliman University with a single breeding pair and 23 crocodiles in total. The Crocodile Farming Institute, operated by the Philippines government, is breeding C. porosus and C. mindorensis for commercial and conservation purposes. CFI acquired 204 C. mindorensis between 1987 and 1992 from both the wild and private captive sources. Successful captive breeding was initiated in 1989. The CSG reviewed this program in 1992 and 1993, making extensive recommendations for improved operations (Messel et al. 1992, 1993). The captive stock has steadily increased from 265 (1992), to 349 (1993) and 500 (1994) of which 33 were adult females producing eggs (Anon. 1993). Annual production of live hatchlings exceeded 500 in 1993 and 1994 (Ortega, Regoniel and Ross 1994). A number of private zoos and collections in the Philippines hold crocodiles but most of these are thought to be Crocodylus porosus as the majority of privately held C. mindorensis have been acquired by CFI.

Two overseas breeding programs were initiated with stock from the Silliman University project. Gladys Porter Zoo in Texas, USA, has two pairs and two excess males and has repatriated some of its hatchlings to the Philippines. Melbourne Zoo in Australia received a sub-adult pair in 1993 and will also cooperate with the Philippine program. Melbourne Zoo has also developed a public education program with posters in conjunction with CFI. In addition, a small number of C. mindorensis are held by zoos and private collections in USA and Europe.

Given the pessimistic situation of the natural habitat, it seems likely that captive breeding will be the central activity for the conservation of this species for some time to come. Refinement of this program is needed to include analysis of founder stock base, genetic diversity and optimal exchange of genetic stocks for maintainance of diversity. Continued support of the captive breeding program, integration of the diverse breeding programs, and continued assessment of the feasibility for reintroduction should be encouraged.

Priority projects

High priority

Development of a national crocodile management program: Philippine crocodiles are presently found in only one officially protected area, the Lake Naujan National Park. However, effective protection of crocodiles is not evident at this site, and better enforcement is needed. A national management plan for C. mindorensis and C. porosus needs to be drawn up outlining a conservation policy. Areas should be identified where the protection of crocodiles could be reasonably certain, and the feasibility of declaring them as reserves determined. Crocodile conservation is not a popular topic in the Philippines and efforts to enlist more public support, through educational campaigns or through sustainable management should be encouraged.

Coordination of captive breeding program: Captive breeding should be integrated on a cooperative world wide basis using current techniques for maintaining genetic diversity in anticipation of eventual reintroduction from captive stocks.

Moderate priority

Continued surveys of the status and distribution of the species: Although relatively good survey data are available, most were conducted in the early 1980s and need to be repeated. Many unsurveyed areas are suspected to have crocodiles, but many of these areas are suffering from civil disturbance problems.

Philippine crocodile, Crocodylus mindorensis, Crocodile Farming Institute, Palawan, Philippines.
This Critically Endangered species urgently requires conservation action. Photo by F. W. King.