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).