Crocodylus intermedius

Common names: Orinoco crocodile, Caimán del Orinoco Range: Venezuela, Colombia Revised by John Thorbjarnarson

CITES: Appendix I
CSG Action Plan: Availability of Survey Data – Poor
Need for Wild Population Recovery – Highest
Potential for Sustainable Management – Low
1996 IUCN Red List: CR Critically Endangered, Criteria A.1.c, inferred decline of >80% in 3 generations, reduced area of occurrence. C.2.a. Wild adult population may be less than 250 individuals, with continuing declines and fragmentation.
Principal threats: Habitat destruction, illegal hunting, limited distribution.

Ecology and natural history

The Orinoco crocodile is a large, relatively long-nosed crocodile restricted to the middle and lower reaches of the Orinoco River in Venezuela and Colombia (Thorbjarnarson and Franz 1987). Although this crocodile was found in a wide variety of habitats, including rivers in tropical evergreen forest and piedmont streams in the foothills of the Andes, it reached its greatest numbers in the seasonal rivers of the llanos savanna region (Medem 1981, 1983, Godshalk 1982b, Thorbjarnarson and Hernández 1992). The Orinoco crocodile is a hole nesting species, laying its eggs in seasonally exposed sandbars and riverbanks early in the annual dry season (January–February). Clutch size is typically in the 40–70 range, and the young hatch out during the rise in river levels associated with the wet season (Thorbjarnarson and Hernández 1993a). Reported dry season concentrations of these crocodiles were very dense, a factor which facilitated hide hunting (Medem 1981, 1983). In smaller rivers that are reduced to a series of interconnected or isolated pools during the dry season, crocodiles aestivate in burrows dug into the river banks. Only a moderate amount of ecological information is available for this species. Accounts by Medem (1981, 1983) cover a number of aspects of its ecology in Colombia and Venezuela. Godshalk (1982b), Thorbjarnarson and Hernández (1990, 1993a, 1993b) deal with aspects of the species’ status and ecology in Venezuela. Ecological and behavioral investigations are underway in Venezuela (Thorbjarnarson, pers. comm.).

Conservation and status

The Orinoco crocodile is one of the most endangered New World crocodilians. Commercial overexploitation from the 1930s through the 1960s decimated wild populations and little recovery has been evident since that time. Medem (1974, 1976) surveyed the Colombian llanos in 1974 and 1976, and found evidence of only 280 adult crocodiles throughout a large part of the drainages of the Arauca, Casanare, Meta and Vichada rivers. The species’ current status in Colombia is very poorly known; however, Myrian Lugo from the Estación de Biología Tropical Roberto Franco and investigators employed by the Environment Ministry are carrying out surveys in several parts of the Colombian llanos. Prior to these surveys, the last census work was carried out in the early 1970s by Prof. Medem. Recent indications suggest that remnant populations may be found in parts of the Arauca, as well as in the Casanare, Meta and Vichada Departments. The Orinoco crocodile is legally protected in Colombia but this has had little effect on hunting in the past (Medem 1981). The Colombian government is considering future commercial exploitation of Orinoco crocodiles based on closed-cycle farming. The Ministry of the Environment is developing an experimental breeding program at their Guafal Biological Station in Arauca. Captive breeding of crocodiles for release into the wild is being done at the Estación de Biología Tropical Roberto Franco in Villavicencio. The center is looking for ways to improve the cramped conditions under which the crocodiles are currently kept. A trial release program is being considered for the El Tuparro National Park. The sale of young crocodiles may be becoming a problem. Juveniles caught by fishermen have occasionally been offered for sale and have been confiscated by the Ministry and placed on caiman farms for safekeeping.

New field surveys conducted in 1994–1995 by the National University and Ministerio el Medio Ambiente, indicate that populations of C. intermedius are still present in the Casanare drainage (Cuilito, Cravo Norte, Lipa, Ele and Casanare rivers), and in Meta province near the Serrania Macarena. Populations are very small with the largest estimated at around 50 individuals in the Casanare area (Lugo 1996, Barahona et al. 1996b).

In Venezuela, preliminary survey work has been completed throughout a large part of the crocodile’s range. Remnant populations are found in isolated areas where human impact has been minimal. However, even these populations are under threat today from a combination of factors including habitat destruction, egg collecting, intentional and incidental killing, and the capture of animals for sale. The potential for population recovery may also be inhibited by a large increase in populations of the sympatric common caiman Caiman crocodilus.

Surveys by Godshalk (1978, 1982b) in the late 1970s indicated that populations of the Orinoco crocodile were severely depleted in Venezuela. More recent surveys by Franz et al. (1985), Ramo and Busto (1986), Ayarzagüena (1987) and Thorbjarnarson and Hernández (1992) confirm these findings. Orinoco crocodiles today remain at extremely low densities. The largest known populations are in the Cojedes/Sarare and Capanaparo river systems. The Capanaparo population is not thought to exceed 500 non-hatchlings. The Cojedes population can be divided into three sections with approximately 20 non-hatchlings in the Sacare/Eneal section, 200–400 non-hatchlings in the Caño de Agua section, and 100 in the Caño Amarillo section. However, nesting in 1990 was very reduced. At least 30 nests a year are produced in the Caño de Agua section (Ayarzagüena 1990). Although recent surveys by Seijas and Chavez have shown high population densities (in some areas exceeding 20/km), severe habitat modification in the form of a government-sponsored river canalization project has greatly impacted the Cojedes population over the last few years and will continue to do so in the near future. The river is severely threatened by contamination from agricultural residues and urban sewage, and plans are also being developed to dam an upstream section. Other isolated populations are known to exist in areas of low population density and at least two smaller populations are in reservoirs (Camatagua and the Tucupido; Thorbjarnarson 1988a, Seijas, pers. comm.). Neither appears to offer suitable habitat for the long-term survival of crocodile populations.

The Orinoco crocodile is legally protected in Venezuela (Resolucion No. 95, 1979). In Apure state, crocodile habitat has been set aside in the Cinaruco-Capanapro National Park (also known as Santos Luzardo N.P.) along the Capanaparo and Cinaruco Rivers, but no management plan has yet been implemented for the species. Recent civil unrest in this area has interfered with crocodile research and population monitoring and has left the park without any functioning staff. Also in Apure state, a wildlife refuge was established in 1989 along the Caño Guariquito, with land donated by surrounding ranches. In Guárico state, crocodile habitat is found within the Aguaro-Guariquito National Park. A number of non-governmental organizations, including FUDENA, the Wildlife Conservation Society, the Agencia Española de Cooperación, the UNELLEZ university, private individuals (Tomás Blohm), businesses (Almaca) and the Venezuelan Government have developed a reintroduction/ restocking program for the species. Three sites have been selected for the release of crocodiles, Caño Guaritico Wildlife Refuge and two national parks, Cinaruco-Capanaparo and Aguaro Guariquito. Small numbers of crocodiles have also been released on three private ranches (Hato El Frio, Hato Piñero and Hato El Cedral) and in one reservoir (Tucupido). Captive breeding is carried out at several sites including Hato Masaguaral, Agropecuario Puerto Miranda, Hato El Frio, and at the UNELLEZ university. A program for collecting eggs from the wild has been conducted in the Cojedes and Capanaparo rivers. Crocodiles from the Cojedes have been released on El Frio and in the Caño Guaritico Refuge. Eggs and juveniles taken from the Capanaparo have been returned to their site of origin. The first group of 31 captively reared young were released in April 1990 in Caño Macanillal on Hato El Frio. As of December 1994, 1,054 crocodiles 1–4 years of age have been released (Table 5). A year-long radio telemetry study of released crocodiles was carried out by Muñoz and Thorbjarnarson in the Capanaparo River, and the results of this study suggest that reintroduction can be a viable management technique to speed population recovery. Periodic follow-up surveys have also been conducted on Hato El Frio and in the Caño Guaritico. Monitoring of released crocodiles in the Aguaro-Guariquito National Park is also being planned. FUDENA, PROFAUNA, and members of the Venezuela Crocodile Specialist Group have been working on the production of Orinoco Crocodile Action Plans. A series of recommendations has been produced, stressing the need to:

1. Assess the current status of wild populations and their habitat,
2. identify and legally protect areas containing viable wild populations of crocodiles,
3. promote the establishment of protected areas on private land,
4. promote more in-depth bioecological studies on crocodiles,
5. optimize the functioning of the captive breeding centers and establish a long-term strategy for the reintroduction and restocking of crocodiles,
6. promote environmental education and community participation programs, and
7. strengthen inter-institutional cooperation and coordination of work.

Priority projects

High priority

Population status in Colombia: Virtually nothing is known about the present status of this species in Colombia. As a first step towards undertaking a conservation program work urgently needs to be undertaken to determine if viable populations remain.

Re-initiation of crocodile work in the Cinaruco-Capanaparo National Park, Venezuela: Civil unrest has resulted in the cessation of crocodile research and conservation activities in this park. The Venezuelan National Parks department needs to re-establish their presence in the park, and crocodile monitoring and nest protecting activities should be reinstituted.

Monitoring of populations of released crocodiles in Venezuela: Crocodiles have been released into three protected areas and several private ranches. Monitoring of these crocodiles has been done, but sporadically. A better coordinated system of follow-up surveys needs to be developed to assess the efficacy of these releases as a conservation technique.

Moderate priority

Conduct surveys in peripheral parts of the species range in Venezuela: Population surveys have covered much of the llanos region looking for remnant crocodile populations. Recent survey work has found surviving populations in isolated areas outside of typical crocodile habitat, including small rivers in the foothills of the Andes, and in forested regions in the south of the country. Additional surveys need to be conducted to look for unknown populations.

Analysis of genetic diversity within and among populations: Many of the conservation plans for this species depend on restocking and reintroduction programs. However, nothing is known about genetic variation among populations. Since many of the remaining populations exist in peripheral habitats, the possibility of genetic differentiation should be explored as part of an overall conservation plan.

Identify areas for reintroduction of crocodiles in Colombia: Orinoco crocodiles are now being bred in small numbers in Colombia with the intention of releasing them back into the wild. As part of population surveys now being initiated, areas need to be identified for trial releases and monitoring.

Orinoco crocodile, Crocodylus intermedius, Masaguaral, Venezuela.
Photo by J. Thorbjarnarson.