Black caiman  (Melanosuchus niger)

The black caiman is classified as Least Concern (LC) on the IUCN Red List (1).

This impressive aquatic hunter is the largest of all alligator species, with reports of individuals measuring six metres (2). The black caiman (Melanosuchus niger) superficially resembles the American alligator (4), and as its name suggests, its protective armoured skin is dark in colour. Pale yellow or white bands of dots pattern the sides of the body, while the lighter grey head has dark bands across the jaws (4). As the caiman matures, this banding gradually fades (2). The snout is fairly wide at the base but becomes rather narrow and pointed and (4), like other caiman, a bony ridge extends from above the large eyes, down the snout (2).

The black caiman occurs mainly in the Amazon Basin, although its range does also extend further north (4). It occurs in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Venezuela (2), and in French Guiana, where the largest populations remain (4).

This aquatic reptile occurs in shallow, freshwater habitats such as slow-moving rivers, streams and lakes, and ventures into flooded savannah and wetlands (2) (4).

Black caiman typically hunt at night, using their acute sight and hearing to locate their prey (2). Fish comprise the major part of the black caiman’s diet, particularly catfish and the much-feared piranha, but adult black caiman also tackle much larger prey such as capybara, turtles and deer (4). Domestic animals such as dogs and pigs may be taken by large adult caiman, and there are even reports of people being the victim of an attack. Juvenile black caiman stick to smaller foods, including crustaceans, other invertebrates such as snails, and fish (4).

Female black caiman are thought to start nesting during the dry season when water levels fall and fish are forced to congregate in shallow pools, providing an easy and plentiful meal (4). Plant material is used to build a mound nest measuring about 1.5 metres across, into which a large clutch of up to 65 eggs are laid (4). The female will remain close to the nest, waiting for between 42 and 90 days until the eggs begin to hatch, before opening the nest to assist with the hatching process (2). As many females often nest within close proximity, large numbers of hatchlings all emerge at once at the beginning of the wet season, gaining some safety in numbers (2).

For many years, the black caiman was heavily hunted for its tough skin which produces shiny, black leather (2). Intensive hunting began in the 1940s, and continued into the 1970s and beyond (2) (4), with around an incredible 66,000 hides being exported from Colombia each year in the early 1970s (4). As a result of this extreme hunting pressure, the overall population of black caiman declined by 99 per cent over the last century and it is now virtually extinct in some locations, such as Colombia and the Amazon River itself (4).

Illegal hunting continues to impact the black caiman, in addition to the destruction of its habitat, through deforestation and the burning of swamplands (2). Competition with the more numerous spectacled caiman (Caiman crocodilus) may also inhibit the recovery of black caiman populations (2).

The impact of reduced black caiman numbers can be felt in some areas, such as Brazil and Bolivia, where capybara populations, free from this voracious predator, have increased, causing a rise in crop damage. Similarly, an increase in piranha numbers in flooded pastures has resulted in an increase in attacks on cattle (4).

Except for certain populations in Brazil and Ecuador, the black caiman is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in this species is only permitted in exceptional circumstances. Those other populations are listed on Appendix II of CITES, meaning that annual quotas are set and the trade is carefully monitored (3). In nearly all the countries in which the black caiman is found, the species is protected or is included in laws prohibiting commercial hunting. However, these laws can be difficult to enforce and illegal hunting remains a significant problem (5), compounded by the fact that black caiman skins can be difficult to differentiate from the more common spectacled caiman (2) (5). In 1990, a captive breeding and reintroduction programme was initiated in Bolivia (5). As well as enforcing existing laws, captive breeding and reintroduction programmes need to be implemented in other countries to assist the recovery of this remarkable reptile (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on the black caiman see:

• Crocodilian Species List:
  www.flmnh.ufl.edu/cnhc/csp_mnig.htm