Can tolerate a reasonable degree of salinity. If environmental conditions become too harsh, they will burrow into mud and aestivate. A triangular ridge is present on the heavily-ossified upper eyelids, vaguely reminiscent of those on the dinosaur Allosaurus . Juveniles are yellow in colour with black spots and bands on the body and tail. As they mature, they lose this yellow colour and the markings become less distinct.
Adults are dull olive-green.
The different subspecies vary in colour, size and skull shape. As they grow, various vertebrates take up a greater percentage of the diet. These include fish, amphibians, reptiles and water birds. Observations show that as conditions become drier, caimans stop feeding. Cannibalism has been reported under such conditions.