Caimans differ from alligators by snout and belly armor
Caimans—from Taíno kaiman—are alligatorids of subfamily Caimaninae, sister lineage to true alligators. They lack a bony septum between the nostrils and wear overlapping ventral armor plates, among other tells. Extinct Purussaurus reached roughly 7.6–10 meters in the Miocene.
Six species of caiman live in the marshes, swamps, lakes and mangrove-lined rivers of Central and South America, mostly active by night. Most are modest crocodilians, topping out at 6 to 40 kilograms and typically 2 to 2.5 meters long. The giant is the black caiman of the sluggish rivers and lakes around the Amazon basin, which can pass 4 meters and 450 kilograms. At the small end, Cuvier's dwarf caiman stays between 1.2 and 1.5 meters.
Compared with their alligator cousins, caimans have longer, sharper teeth, belly scutes built from two bony halves joined by a seam, and no bony wall dividing the nasal passages. They move with a quicker, more crocodile-like agility, and calcium rivets in their scales make the hide stiffer. Scientists define the subfamily as the spectacled caiman plus every species nearer to it than to the American alligator, while the inner group Jacarea gathers the broad-snouted, spectacled, yacare and black caimans. Where the lineage begins is disputed: a 2022 analysis placed certain Late Cretaceous forms among early alligators and dated the first sure caimans to the earliest Paleocene, but a 2024 study grouped Brachychampsa and its kin at the base of the caiman branch as Brachychampsini.
Fish make up most of the diet, supplemented by insects, birds, small mammals and reptiles. Adults face few natural enemies beyond jaguars, anacondas and crocodiles, which mostly take smaller kinds such as spectacled and yacare caimans; people, hunting them for meat and skin, are the main threat. In summer heat or drought a caiman may dig a burrow and wait it out in aestivation.
A female heaps up a nest that can span more than 1.5 meters and lays 10 to 50 eggs, which hatch in about six weeks. She then leads the young to a shallow pool to learn swimming and hunting, and spectacled caiman juveniles may stay together in pods for as long as 18 months.
Source: Caiman
