Spectacled caiman (Caiman crocodilus)
|Also known as:||Common caiman|
|Size||Total length: up to 3 m (2) (3)|
Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix I and II of CITES (4).
A relatively small to medium sized crocodilian, the spectacled caiman is named for the bony ridge between the front of the eyes, which appears to join the eyes like a pair of spectacles. Although potentially growing up to 3 metres in length, the male rarely exceeds about 2.5 metres, while the female is smaller, at a maximum of up to 2 metres (2). In addition to the bony ridge between the eyes, the spectacled caiman also possesses a triangular ridge on top of the eye (2), and, like other members of the alligator family, it has a relatively broad, blunt snout (3) (5).
Juvenile spectacled caimans are yellowish in colour, with black spots and bands on the body and tail. As an individual matures, it becomes more olive-green, and the markings become less distinct. Interestingly, this species may have some ability to change colour (2). The spectacled caiman is one of the most variable of the New World crocodilians (6), and three subspecies are generally recognised, which differ in colour, size and skull shape (2) (3) (6). A fourth subspecies, Caiman crocodilus yacare, is now regarded as a separate species, the Yacare caiman (Caiman yacare), while populations of Caiman crocodilus fuscus in Mexico potentially comprise a further subspecies, Caiman crocodilus chiapasius (2) (6).
The spectacled caiman is the most widely distributed New World crocodilian, ranging from Mexico in the north to Peru and Brazil in the south (1) (2) (3) (6). Caiman crocodilus crocodilus is found in Venezuela, Colombia, Peru, Brazil, and north and east Bolivia; C. c. fuscus (brown caiman) is found throughout Central America and into Colombia, Venezuela and Ecuador, and has also been introduced to Cuba, Puerto Rico and Florida, USA; and C. c. apaporiensis (Rio Apaporis caiman) is known only from the upper Apaporis River in Colombia (2) (6).
The spectacled caiman is a highly adaptable species, found in virtually all lowland wetland and riverine habitats throughout its range, although generally preferring areas of still water, such as lakes, ponds and marshes, as well as slower-flowing rivers (2) (3) (6). It can also tolerate a reasonable degree of salinity (2).
Like all crocodilians, the spectacled caiman is a superbly adapted aquatic predator. Most feeding activity takes place during the wet season, with juveniles feeding mainly on insects, crustaceans and snails, while adults take fewer insects, but also take fish, amphibians, reptiles and water birds. The largest individuals are also capable of taking mammals such as deer and pigs (2) (3) (7), and, in dry conditions when food is scarce, may also cannibalise smaller caimans (2) (3). The spectacled caiman has been recorded to use the body to trap fish against the shore, making the fish easier to capture (8). If environmental conditions become too harsh, this species may burrow into mud and aestivate (2) (3) (5).
The spectacled caiman usually mates from around May and nests during the wet season, between July and August (2) (9), ensuring that abundant food and suitable habitat will be available when the young hatch (2) (10). The female lays around 20 to 40 eggs in a nest consisting of a mound of soil and vegetation (2) (3) (6), and the young hatch after about 90 days (2). As in all crocodilians, the sex of the young is determined by the temperature of incubation, with lower temperatures producing mainly females, and higher temperatures mainly males (3) (5). The female remains near the nest throughout the incubation period, although eggs are often taken by predators or lost to flooding (2) (3) (10).
When the young begin to hatch, the female excavates the nest (10), sometimes even helping eggs to hatch by gently rolling them in the mouth, and will then carry the hatchlings to water and remain with them for some time (3) (5) (6). Young spectacled caimans often form ‘nursery groups’, consisting of the offspring from several different parents. The female spectacled caiman shows an unusually high level of maternal care. One female will usually take charge of the group of young, even those that are unrelated (2), and will even lead the whole group overland to a new pool if the nursery pool dries up, calling to them and apparently ensuring none get left behind (11). The young spectacled caimans may stay together in a group, near the nesting site, for up to 18 months, after which they disperse and begin to compete for territories (10) (12). Maturity is reached between 4 and 7 years, corresponding to a length of about 1.2 metres in the female and 1.4 metres in the male (2) (3) (6) (9), although small mature males are often excluded from breeding by more dominant individuals (2) (9).
The skin of the spectacled caiman is less commercially valuable than that of many other crocodilians, due to the extent of bony deposits in the scales of the belly (2) (3) (6). However, since the depletion of other, more valuable species by the 1950s, the spectacled caiman has been heavily hunted, and currently supplies the vast majority of the hide market in the Americas (2) (6). In some areas, the spectacled caiman is also hunted for its meat and eggs (13) (14), and it has also been collected for the pet trade (2). However, despite some local population declines, the species as a whole remains one of the most widespread and abundant of all crocodilians. It is very adaptable, and has readily moved into areas where larger competitors, such as the black caiman (Melanosuchus niger) and the American and Orinoco crocodiles (Crocodylus acutus and C. intermedius), have been removed or reduced in numbers (2) (3) (6). The spectacled caiman has also benefitted from the construction of man-made water bodies, such as in the cattle ranches of Venezuela (2) (6) (15).
The major threat to the spectacled caiman is now illegal hunting (2) (6), while habitat destruction and environmental pollution, such as contamination with heavy metals, may also be problems (6) (16). Most under threat is the subspecies C. c. apaporiensis, which has a highly restricted range in Colombia, and the species is also severely depleted in El Salvador (2). However, in areas where the spectacled caiman has been introduced, often through the release of unwanted pets, the species may be responsible for declines in native wildlife, and is thought to have contributed to the disappearance of the Cuban crocodile, Crocodylus rhombifer, from the Isle of Pines, Cuba (2) (6).
International trade in the spectacled caiman is carefully regulated under its CITES listings (4), and the species is also legally protected in several countries, with hunting restrictions in others, although protection is rarely effectively enforced (2). Legal trade involves ‘sustainable use’ programs, such as captive breeding, harvesting of wild populations, and ranching, although the low value of caiman hides often makes the economic viability of these programs questionable, and the effects on wild populations need to be investigated (2) (3) (6). Since 1983, Venezuela has run the largest cropping program for any crocodilian species, based on controlled hunting of spectacled caimans by private landholders. This is said to have generated significant economic benefits and is believed to be sustainable (6) (15).
As well as continued enforcement on illegal trade (6), high priorities for spectacled caiman conservation include urgent research and action for the little-known C. c. apaporiensis, long-term ecological studies, monitoring of harvest levels, and clarification of the boundaries between the subspecies, which would also aid in the implementation of trade controls (2) (6). Although adaptable, and able to recover quickly when hunting pressure is reduced (3) (6), the continued success of the spectacled caiman may rely on appropriate management and on the long-term viability of sustainable use programs.
To find out more about the spectacled caiman and its conservation see:
- Detailed range map for the spectacled caiman:
- IUCN/SSC Crocodile Specialist Group:
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- Aestivate: to become dormant during the summer or dry season, analogous to hibernation in winter.
- Crocodilian: a member of the order Crocodylia, a group which includes crocodiles, alligators, caimans and gharials.
- Crustaceans: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Incubation: the act of incubating eggs; that is, keeping them warm so that development is possible.
- Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
- Territory: an area occupied and defended by an animal, a pair of animals or a colony.
IUCN Red List (July, 2014)