Caiman

Caimans are distinguished from alligators, their closest relatives, by a few defining features: a lack of a bony septum between the nostrils, ventral armor composed of overlapping bony scutes formed from two parts united by a suture, and longer and sharper teeth than alligators. Caimans also tend to be more agile and crocodile-like in their movements. The calcium rivets on caiman scales make their hides stiffer than those of alligators.

Several extinct forms are known, including Purussaurus, a giant Miocene genus that grew to 7.6–10 m (25–33 ft) and the 5.89 m (19.3 ft) Mourasuchus, which had a wide duck-like snout.

Behavior

Caimans are predators and, like alligators and crocodiles, their diet largely consists of fish. Caimans also hunt insects, birds, small mammals and reptiles.

Because of their large size and ferocious nature, caimans have few natural predators within their environments. Humans are their main predators, because the animals have been hunted for their meat and skin. Jaguars, anacondas and crocodiles are the only other predators of caimans, although they usually prey on the smaller specimens or specific species of caiman such as the Spectacled Caiman and Yacare caiman. During summer or droughts, caimans may dig a burrow and go into a form of summer hibernation called aestivation.

Female caimans build a large nest in which to lay their eggs. The nests can be more than 1.5 m (4.9 ft) wide. Female caimans lay between 10 and 50 eggs, which hatch within about six weeks. Once they have hatched, the mother caiman takes her young to a shallow pool of water, where they can learn how to hunt and swim. The juveniles of spectacled caiman have been shown to stay together in pods for up to 18 months.