Caimans belong to the subfamily Caimaninae and are crocodilians. Just like all crocodilians, caimans are a type of reptile. They make up one of the two subfamilies of the family Alligatoridae (the other subfamily contains alligators).

The taxonomy of the now living caimans looks like this:

     Subfamily Caimaninae
Genus Paleosuchus
+ Cuvier's Dwarf Caiman, Paleosuchus palpebrosus
+ Smooth-fronted Caiman, Paleosuchus trigonatus
Genus Caiman
+ Yacare Caiman, Caiman yacare
+ Spectacled Caiman, Caiman crocodilus
# Rio Apaporis Caiman, C. c. apaporiensis
# Brown Caiman, C. c. fuscus
+ Broad-snouted Caiman, Caiman latirostris
Genus Melanosuchus
+ Black Caiman, Melanosuchus niger

The subfamily contains now extinct genera as well, but I have only listed genera containing now living species.  

Caimans look like alligators but grow smaller. The smallest species of all crocodilians is a caiman species called Cuvier’s dwarf caiman (Paleosuchus palpebrosus) that grows to be a mere 1.5 m / 5 ft. The largest of the caimans is the Black caiman (Melanosuchus niger) that grows to be 6 m / 20 ft and is one of the largest animals of South America.

Caimans are found in South and Central America and are found in rivers, streams and lakes. The Spectacled caiman (Caiman crocodilus) can also be found in southern Florida where it has established a breeding population after being released into the wild. The species used to be a popular pet that was released when it grew too big for the owners, which brings up an important point: caimans are smaller than other crocodilians and might seem more suitable as pets but it is important to remember that one will still need the space and resources to house a large animal. Even an adult Cuvier’s dwarf caiman is a large animal that will require a lot of room.

The Black caiman is unique among crocodilians by the fact that it never looses its baby stripes giving it an attractive pattern. Most crocodilians are born with baby stripes that help them blend into the vegetation and hide from predators. Other crocodilians loose their stripes as they grow larger while the black caiman keeps them.

Caimans lay 14-60 eggs depending on size and species. The eggs are laid in a mound dug by the female. The female guards the nest and then indirectly the young by guarding her territory. The eggs of different species take different times to hatch but roughly 70 days are to be considered normal. The temperature in the nest decides the sex of the baby caimans.

Most of the caiman species are endangered. The main reasons for the decline in population are habitat destructions and hunting for their skin and meat as well as the collection of eggs. Conservation efforts are being made to save several of the most endangered species.