Crocodylus rhombifer

Common names: Cuban crocodile, Cocodrilo, Criollo, Cocodrilo perla Range: Cuba, Cayman Islands (extinct)

CITES: Appendix I (Registered captive breeding facility)
CSG Action Plan: Availability of Survey Data – Adequate
Need for Wild Population Recovery – Highest
Potential for Sustainable Management – Moderate
1996 IUCN Red List: EN Endangered – Criteria A.1.c. and e declines of >80% in 3 generations in extent of occurrence, possible effects of hybridization. B.1 and 2c area of occupancy less than 500km² , single location.
Principal threats: Limited distribution, Habitat destruction, Introduced exotics.

Ecology and natural history

The Cuban crocodile has the smallest known natural distribution of any extant crocodilian. Its present distribution is restricted to the Zapata Swamp in southwestern Cuba. The persistence of a small remnant population in the Lanier Swamp on the Isle of Pines (Isla de Juventud) is unconfirmed. However, in the recent past this species was more widely distributed on the main island of Cuba (Varona 1966). Skeletal material shows that this species was found on the Cayman Islands into historic times (Morgan et al. 1993) and in the Bahamas (Franz et al. 1995).

The Cuban crocodile is a medium-sized species whose maximum reported length is 4.9m, but normally does not exceed 3.5m (Varona 1966). This species is normally restricted to freshwater habitats. The Zapata swamp, currently supporting the species’ only known wild population, is an extensive freshwater marsh not unlike the Everglades region in southern Florida, USA.

Although the Cuban crocodile is smaller than the American crocodile, when maintained together the Cuban crocodile is almost always the behaviorally dominant species (Varona 1966). The Cuban crocodile has a pugnacious disposition and a well-deserved reputation as a good jumper.

Some confusion has existed over the nesting mode for this species. Varona (1986) states that nests consist of holes excavated into the substrate, usually peat or soil with plants mixed in. However, in captivity this species usually constructs mound nests, which are also reported from the wild. Clutch size is typically 30–40 eggs.

Hybridization of this species with C. acutus have been reported under captive conditions in Cuba, and it may occur in the wild as well (Varona 1966, Ramos et al. 1994). Reproductive activity of C. rhombifer occurs one to two months later than the sympatric C. acutus, restricting hybridization to occasional contacts between C. acutus males and C. rhombifer females (Ramos, pers comm.). Hybrids are also known from C. rhombifer males and C. siamensis females in captivity (Thang 1994). Hybrids are thought to be fertile.

Conservation and status

Reduction of the species’ distribution is evident. At one time the Cuban crocodile was more widely distributed on Cuba and surrounding islands. Today, its range in the wild appears to be restricted to the Zapata Swamp. Cuban crocodiles were, until recently, also found in the Lanier Swamp on the Isle of Pines. However, this population is reported to be extirpated, with the introduction of the common caiman possibly playing a significant role. A survey in the Zapata swamp (Ramos et al. 1994) used mark and recapture methods to estimate population densities of 11–104 individuals per km² . Total population in the wild is thought to be in the order of 3,000–6,000 individuals in an area of 300km² in the southwestern part of the Zapata swamp. Reports from as early as 1982 (Chabreck 1982) indicated substantial recovery of this population which is confirmed by the recent survey. Active measures are underway to ensure that this population remains well protected. Despite recent reassuring information on the status of this species in the wild it remains extremely vulnerable due to its restricted distribution. Wild populations have been greatly reduced and little is known of the species’ behavior and ecology.

In 1959 and 1960, several hundred adults were collected and placed in pens with the objective of both conserving the species and developing commercial use. The largest farm, at Laguna del Tesoro, has about 1,500 breeding adults and produces 1,000–1,500 captive bred offspring annually. When the crocodiles were first placed in the pens in 1959, C. rhombifer were mixed with C. acutus. This resulted in hybridization between the two species. Since 1976, the two species have been separated and a stock of pure C. rhombifer has been isolated. The degree of genetic introgression remaining in the captive Cuban stock remains unknown. A second farm at Cayo Potrero on Isla de Juventud has 40 breeding stock obtained from the Laguna Tesoro farm but is not yet producing offspring. Products from the farms are meat for local consumption and culled juveniles for a taxidermy industry providing curios to the tourist trade. With the approval of the Laguna Tesoro farm as a captive breeding facility under CITES in 1994, international trade in skins from captive bred Cuban crocodiles has been initiated.

In 1985, 107 Cuban crocodiles were sent as a gift from Cuba to the Government of Vietnam. Four of the crocodiles were adult size and the remainder approximately 1 year old. Two of the juveniles died in transit and the remainder were distributed to several government organizations (zoos and forestry departments) throughout the country. By 1994, approximately half of the crocodiles were known to have died. Of the remainder, a number of adults have been bred with C. siamensis and approximately 100 hybrids are thought to be in captivity at present. Discussions are underway to bring all C. rhombifer and hybrids together at one location and minimize the risk of releasing them to the wild (Thang 1994).

A captive breeding program and studbook involving 54 captive Cuban crocodiles (16.27.11) in the USA is coordinated by the American Zoo and Aquarium Association (AZA) (McMahan 1993).

Priority projects

High priority

Protection of the wild population in the Zapata Swamp: The restricted area occupied by Cuban crocodiles needs to be given effective protection to ensure the survival of the species in the wild.

Establishment of alternative wild populations: Because of its limited distribution, the establishment of additional wild populations as insurance against unanticipated natural or human induced catastrophe is needed.

Status of the Cuban crocodile in the Lanier Swamp, Isla de Juventud: Until recently, Cuban crocodiles were also found in the Lanier Swamp. Recent reports suggest they have been extirpated, and that the introduction of the common caiman played a significant role. Surveys need to be conducted to determine the status of crocodilian populations on this island and plan active management alternatives, such as the reintroduction of Cuban crocodiles.

Moderate priority

Ecological interactions between Cuban crocodiles and the introduced Caiman crocodilus in the Lanier Swamp: The introduction of the common caiman into the Lanier Swamp is thought to have played an important role in the apparent extirpation of C. rhombifer from this area. If any Cuban crocodiles remain in the swamp, investigations of caiman-crocodile interactions should be undertaken.

Monitoring of the population: A program of regular annual monitoring of the wild C. rhombifer population should be developed from the current Cuban field research activities. This program should concentrate on repeatable standard methods that will provide data on the year to year trends of the population. Standardization of the locations, survey transects, days worked, and techniques applied will all improve the quantitative and comparable quality of the results.

Coordination of captive breeding programs: Three independent captive populations exist in Cuba, in the USA and in Vietnam. Assessment of the severity of introgression by hybridization and coordination to ensure optimum genetic diversity in the captive stock is needed.

Cuban crocodile, Crocodylus rhombifer, Lanier Swamp, Isla de Juventud,
Cuba. An individual released from the farm for restocking the wild
population. Photo by P. Ross.