DISTRIBUTION:
[CLICK ON MAP FOR DETAILED RANGE]
Brazil, Colombia, Costa Rica, Cuba*, Ecuador, El Salvador, Guyana, French Guiana, Guatemala, Honduras, Mexico, Nicaragua, Panama, Peru, Puerto Rico*, Suriname, Tobago, Trinidad, United States*, Venezuela
[* = introduced - C. c. fuscus in Cuba and Puerto Rico]

HABITAT:
Extremely adaptable species found in virtually all lowland wetland and riverine habitat types throughout its range - particularly as a result of the now-diminished ranges of sympatric competitors (e.g. C. acutus, C. intermedius, M. niger) - although it generally prefers areas of still water. The extensive Panatal floodplain provides a perfect habitat for the caiman during the rainy season. Caiman crocodilus has the widest distribution of any species in the Alligatoridae family. Can tolerate a reasonable degree of salinity. If environmental conditions become too harsh, they will burrow into mud and aestivate.

STATUS:
     CITES: All subspecies Appendix II, except C. c. apaporiensis (Appendix I)
     IUCN Red List: LRlc (LOW RISK, LEAST CONCERN)
     Estimated wild population: over 1,000,000
Summary: The most common of all crocodilian species, although some populations are locally depleted

APPEARANCE:
[click on image for enlargement]
A relatively small to medium sized crocodilian (males generally reach 2.0 m to 2.5 m, with the largest specimens reported to approach 3 m - but these are undoubtedly rare). Females are smaller, reaching a mean maximum size of 1.4 m, and rare individuals may approach 2 m. Its common name derives from a bony ridge which is present between the front of the eyes (infra-orbital bridge), appearing to join the eyes like a pair of spectacles. A triangular ridge is present on the heavily-ossified upper eyelids, vaguely reminiscent of those on the dinosaur Allosaurus. Juveniles are yellow in colour with black spots and bands on the body and tail. As they mature, they lose this yellow colour and the markings become less distinct. Adults are dull olive-green. This species (probably along with several others, including A. mississippiensis) has shown a limited ability to change colour (metachrosis) due to changes in the distribution of black pigment in melanophore cells. The different subspecies vary in colour, size and skull shape.

DENTITION:
5 pre-maxillary; 13-14 maxillary; 18-20 mandibular
Total no. of teeth = 72-78

IMAGES:
[click on image for enlargement]

Head-on view of floating adult caiman

Top-down view of adult head

Sub-adult caiman partially submerged

DIET:
Juveniles take a variety of aquatic invertebrates (insects, crustaceans, molluscs). As they grow, various vertebrates take up a greater percentage of the diet. These include fish, amphibians, reptiles and water birds. Older animals are capable of taking larger, mammalian prey (e.g. wild pigs). Observations show that as conditions become drier, caimans stop feeding. Cannibalism has been reported under such conditions. The ecological importance of this species has been demonstrated in terms of nutrient recycling - nitrogenous waste re-enters the ecosystem to the benefit of other plants and animals. In areas where this species has become depleted, fish populations have also shown a decline. They are also reputed to control piranha numbers. While it has been stated that little evidence is available to support this, C. yacare does demonstrate this particular dietary preference. In reality, it is likely that C. crocodilus is very much a generalist and adaptive predator, given its ecological success.

BREEDING:
Females become sexually mature at 1.2 m, which may be between 4 and 7 years depending on the population. Males mature at larger sizes than females, but similar ages (1.4 m and 4 to 7 years). Social status affects growth rate and hence readiness for breeding. Less dominant animals grow less quickly due to stress, and often do not get the chance to breed. Gonads begin to increase in size towards the end of the dry season (April to May) and peak at the start of the wet season (May to June). Courtship and mating generally occur between May and August, and the eggs (from 14 to 40, mean size being around 22) are laid during the wet season (July to August) in a mound nest constructed from soil and vegetation. Location is generally under cover, but some are sited in more open areas or on floating mats of vegetation. Nests may be shared by females, a strategy which may help to increase the survival of juveniles from each parent. Nest predators include large, monitor-like Tupinambis lizards, which can destroy up to 80% of nests in an area. Females will remain close to nests in an attempt to dissuade predators. When the juveniles hatch after around 90 days, there is usually a plentiful supply of invertebrate food available due to the timing of hatching. In the period following hatching, juveniles will remain in groups close to the female, and will follow her around even over land between different pools. One female may take over the maternal duties for multiple groups of hatchlings (pods) from different parents. During this time, social hierarchies are established between the juveniles.

CONSERVATION:
This species has actually benefited from commercial utilisation and over-hunting of other species within its range (Crocodylus acutus, C. intermedius and Melanosuchus niger), taking over habitat from which it would otherwise have been out-competed by healthy populations. The skin of C. crocodilus is not ideally suited to tanning, as the ventral scales contain well-developed osteoderms. Only the lateral flanks provide skin of an acceptable quality for tanning. Hunting pressures remained relatively low, therefore, until populations of the sympatric crocodilian species became depleted in the 1950s, when hunting of C. crocodilus intensified. The numbers of caimans harvested since then has been huge, and they currently supply the vast majority of the hide market in America. Leather from this species is often passed off as Alligator mississippiensis or other species.

Despite pressure from hunting and also collection for the pet trade, however, existing surveys suggest that populations are in relatively good condition in most areas (e.g Venezuela). This seems to reflect the adaptability of the species, its reproductive potential, and the increase in available habitat through the removal of competing species and an increase in man-made water bodies (e.g Brazilian Panatal, Colombia, Venezuela). However, it is these factors which make it difficult to determine the overall status of the species, as populations are faring less well in other areas - surveys reveal severe depletion in El Salvador. More up to date surveys are required for clarification, and to examine the interactions between the different subspecies. Further taxonomic work would make control measures easier to implement, as currently identification of different subspecies can be difficult. The major threat to this species and its subspecies is currently illegal hunting. Smuggling rings operating through Thailand and Singapore are extremely damaging to individual populations, and greater control measures and more effective legislation are needed.

The subspecies C. c. apaporiensis is under severe threat in Colombia. Feral populations of C. crocodilus are creating problems for other species of crocodilians and native wildlife, however. These populations have become established in three countries. The introduced population in Cuba is thought to have been primarily responsibly for the dramatic decline and probable disappearance of Crocodylus rhombifer from the Isle of Pines.

Sustainable use programs are well developed in several countries. Most of these rely upon regular cropping of wild populations. The long-term effects of this cropping need to be investigated. The reproductive potential of this species makes properly controlled sustainable yield programs look promising. Farming and ranching programs, while they exist, may be uneconomical in the long run, given the value of the hide and the number of animals which need to be culled in order to produce a profitable amount of hide.

MORE INFORMATION:
For more information on distribution and conservation issues for this species,see the CSG Action Plan resource.

SIGNIFICANT REFERENCES: