Comments: Habitat includes coastal mangrove swamps, brackish and salt water bays, lagoons, marshes, tidal rivers, brackish creeks; also abandoned coastal canals and borrow pits. Individuals may wander widely in coastal waters and may range inland into lakes and lower reaches of large rivers. American crocodiles occupy mostly nonsaline waters in the nonbreeding season, move to saline waters when breeding. In Florida, primary habitat is inland mangrove swamps protected from wave action; females use open waters of Florida Bay only for access to nesting sites (Kushlan and Mazzotti 1989).
Eggs are laid in a mounded nest of soil, sand, or peat, or in a hole in the ground (Kushlan and Mazzoti 1989). Florida Bay nest sites usually are at edge of hardwood thickets on small sand beaches, or on high marl banks of coastal creeks, or in mangrove swamps along old canal banks; also on berms of power plant cooling canal systems (Gaby et al. 1985). In the West Indies, nests most often are in the ecotone between Conocarpus-dominated riparian strip and xeric uplands (Schwartz and Henderson 1991). In Belize, most nesting areas were on elevated beach ridges of coarse sand; adjacent shallow brackish lagoons provided critical nursery habitat (Platt and Thorbjarnarson 2000). See also Lutz and Dunbar-Cooper (1984).
In Florida, shortly after hatching, hatchlings disperse from nest sites to nursery habitats that are generally more sheltered, have lower salinity (1-20 parts per thousand), shallower water (generally), and more vegetation cover (USFWS 2007). Lazell (1989) reported that young generally occupy brackish water but seem to do well in full salt water on North Key Largo (Florida), perhaps due to the effect of abundant rainfall.