Caiman crocodilus
Common caiman, Spectacled caiman

Caiman crocodilus, the spectacled, common, or brown caiman, is a crocodilian native to northern South America, Central America, and certain parts of the Caribbean. They are native to the following countries: Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad, Tobago, and Venezuela. They have been introduced into Florida, Cuba, and Puerto Rico. (Bartlett and Bartlett, 2003; Crocodile Specialist Group, 1996; Kohler, 2003; Ross, 1989; University of Southern Mississippi, 2009)

Spectacled caimans are found in freshwater habitats as well as some salt water habitats. Rivers and wetlands, usually slow moving water, are preferred. They are found in both deep and shallow water, as they only need enough depth to submerge their bodies. (Bartlett and Bartlett, 2003; Bartlett and Bartlett, 2003; Britton, 2009a; Grana Raffucci, 2007; Ojasti, 1996)

Spectacled caimans are small to medium-sized crocodilians generally 1.5 to 2.1 meters in length. Historically, maximum reported length was 3 m. At current levels of exploitation, few specimens exceed 2.5 m in length. Females are smaller than males. Average adults are a dull olive to nearly black in color with variable yellow or black crossbands. They have long snouts and their fourth mandibular tooth is not visible from the outside of their closed jaw. Juveniles are yellowish in color with darker bands and spots. A feature that helps to distinguish Caiman crocodilus from other, sympatric crocodilians is the presence of a bony infra-orbital bridge between the eyes. Subspecies vary in color and skull size. (Bartlett and Bartlett, 2003; Britton, 2009a; Grana Raffucci, 2007; Kohler, 2003)

Some weeks after courtship and copulation, with internal fertilization, females lay their oval, hard-shelled eggs in a newly made mound of leaf litter and other vegetation. Once the eggs are laid, the female will cover the nest. Females, and sometimes males, guard their eggs against nest predators. Temperature influences sex determination during incubation. An average nest temperature of 30 degrees C will produce mostly females and 34 degrees will produce mostly males. After an incubation period of 65 to 104 days the babies will hatch out of their eggs and move to the nearest water, with some help from their parents. Once the juveniles have hatched, they will stay near their parents for about 1.5 years. Juveniles then grow to adult size at around 1.2 to 1.4 meters in length. Once juveniles reach minimum adult size, they are able to reproduce. If they survive long enough, they can continue to grow until reaching a size that may exceed 2.4 meters. (Bartlett and Bartlett, 2003; Britton, 2009a; Grana Raffucci, 2007; Kohler, 2003; Ojasti, 1996)

Mating typically occurs in the wet season from April to August, depending on local climatic conditions. Males can breed with multiple females and females can breed with multiple males. Courtship behavior involves prospective mates swimming together, rubbing backs, bellowing, touching snouts, circling each other, and bubble-blowing. Both sexes use these behaviors to attract their mates. After a female mates with a male she will build a nest in the males territory. There, the male and female will guard the nest, eggs, young, once they are hatched. (Britton, 2009a; Britton, 2009b; Grana Raffucci, 2007; Kohler, 2003; Mertz, 2009; Ojasti, 1996)

Spectacled caimans reach sexual maturity at sizes of about 1.2 meters for females and 1.4 meters for males, corresponding to from 4 to 7 years old. Social status affects growth rate and reproduction. Some younger, smaller caimans will be unable to mate because of social stress because of the presence of larger, more dominant caimans. Courtship and copulation occurs between May and August. Eggs are laid from July to November, depending on local climatic conditions. Females lay from 10 to 30 eggs. Incubation usually requires between 65 and 104 days. Sex is determined by temperature in the nest about midway through incubation. The decomposing vegetation in the nest, which may be a meter high and 2 meters in diameter, may help retain temperatures at the proper level. After hatching, the parents may excavate the juveniles from the nest and help them out of the eggshell. Once emerged, juveniles stay near their parents for approximately 1.5 years, receiving some protection from predators. (Bartlett and Bartlett, 2003; Britton, 2009a; Britton, 2009b; Grana Raffucci, 2007; Kohler, 2003; Ojasti, 1996)

After copulation, females, sometimes assisted by males, build a nest out of leaf litter. Females lay their eggs in the nest and then cover it with more leaf litter. Females, and occasionally males, guard the nest from predators until they hear the babies call with grunt-like squeaks. Females then help uncover eggs and break the shells open to get the juveniles out. At that point, juveniles stay near their mother, and sometimes within the male parent's territory, for around 1.5 years for additional protection from predators. The parents may incidentally provide some food scraps for the juveniles but, for the most part, juvenile caimans catch food for themselves. After about 1.5 years with their parents, juveniles disperse from their parent's territory. In some situations, young caimans remain closer to their parents for longer periods. (Bartlett and Bartlett, 2003; Britton, 2009a; Grana Raffucci, 2007; Kohler, 2003; Ojasti, 1996; Ross, 1989)

There is very little known about the lifespan of Caiman crocodilus. The longest known lifespan in the wild was estimated at about 60 years old. However, 30 to 40 years might be more normal. The average captive lifespan is 20 years, with a minimum record of 24 years. (Britton, 2009b; Mertz, 2009)

Spectacled caimans live in loose-knit groups but are generally solitary except during mating season. They stay in the same territory and remain immobile for most of the day. During the heat of mid-day they stay submerged, morning to early afternoon they bask on the shore. They are able to rapidly respond to certain situations like catching prey. Spectacled caimans typically feed at night. During mating season, they become territorial and aggressive. Social rank is determined by size, with larger animals being more dominant. Animals with higher social rank tend to have more mating chances during mating season. (Ojasti, 1996)

Home ranges are not large and spectacled caimans generally stay in their home ranges throughout the year. Home range size varies with the structure and richness of the habitat. (Kohler, 2003; Ojasti, 1996; Ross, 1989)

Spectacled caimans use taste, touch, sound, and visual senses for social and reproductive communication. The ability to detect vibrations in the water may aid in prey detection. (Britton, 2009a; Britton, 2009b; Ojasti, 1996)

Spectacled caimans are carnivorous generalists. Prey items change as they grow from smaller to larger caimans. Prey can include insects, snails, shrimp, crabs, fish, lizards, snakes, turtles, birds, and mammals. Spectacled caimans have at least 105 prey items reported in their diet. Cannibalism can occur, especially under drought conditions, when many caimans of different sizes are concentrated in small areas. However this species can be surprisingly unaggressive and tolerant of temporarily dense concentrations during the dry season. (Mertz, 2009; Ross, 1989; University of Southern Mississippi, 2009)

During nesting time, tegu lizards (Tupinambis sp.) can destroy up to 80% of caiman nests in some places. Coatis (Nasua narica) and foxes also raid nests. Juveniles are eaten by large fish, wading birds, large snakes, and other crocodilians. Adult spectacled caimans are able to defend themselves from most potential predators, except humans. (Bartlett and Bartlett, 2003; Britton, 2009a)

Spectacled caimans are predators of aquatic invertebrates, fish, and other aquatic and shoreline vertebrates. In their native range they are important members of riparian shoreline and aquatic communities. Where spectacled caimans have been introduced outside of their normal range, spectacled caimans may have unpredictable, perhaps deleterious effects on prey species. (Bartlett and Bartlett, 2003; Grana Raffucci, 2007)

Within their native range, spectacled caimans are usually the most abundant crocodiles and are the most heavily harvested species by humans for the hide industry. (Britton, 2009a; Grana Raffucci, 2007; Ross, 1989)

Spectacled caimans are potentially dangerous to humans and pets, and they occasionally attack livestock. Their smaller size compared to other crocodilians makes them less of a threat. They become shy and avoid humans in areas where they are frequently hunted. Spectacled caimans have been introduced outside their natural range, such as in southern Florida, and possible negative effects on local naive wildlife are in need of study. (Bartlett and Bartlett, 2003; Grana Raffucci, 2007)

In 1986 and 1988 spectacled caimans were listed by the United States Fish and Wildlife Service as a threatened species. This was due to increased hunting pressure on their populations. Caimans are heavily harvested for their skins to make leather products. The pet and curio trade has also had some degree of responsibility for local population declines. Spectacled caiman populations are still relatively stable in some parts of their range, although they are severely depleted or extirpated in many local areas, especially near human population centers. (Bartlett and Bartlett, 2003; Britton, 2009a; Crocodile Specialist Group, 1996; Ross, 1989)