A caiman (/ˈkeɪmən/ (also spelled cayman[3]) from Taíno kaiman[4][additional citation(s) needed]) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators.

Caimans are native to Central and South America and inhabit marshes, swamps, lakes, and mangrove rivers.

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, plus caimans tend to be more agile and crocodile-like in their movements.

Several extinct forms are known, including Purussaurus, a giant Miocene genus that grew to 12 m (39 ft) and the equally large Mourasuchus, which had a wide duck-like snout.

[8][9] This is a stem-based definition for caimaninae, and means that it includes more basal extinct caimanine ancestors that are more closely related to living caimans than to alligators.

[12] A different study by Adam Cossette and David Tarailo in 2024 recovered Brachychampsa and relatives in a clade at the base of Caimaninae.