Males generally grow to be larger than females. Habitat Crocodiles are prominent and widespread occupants of tropical and subtropical aquatic habitats. They are important to the ecosystems they live in because they keep fish populations in line through selective hunting, and they recycle nutrients. They are also heavily affected by habitat loss and the pollution of aquatic habitats. Crocodiles can live a long time in the wild and sometimes live in the same place for decades.
Crocodiles depend upon wetland habitats.
They have evolved to adapt to most tropical and subtropical wetland types - marshes, rivers, lakes, and lagoons. Because they are large animals, they require a large range of untainted land to live in. The American Crocodile requires hundreds of square miles of undisturbed wetland to keep a stable and large enough population. Threats American Crocodiles are threatened by many human activities. The worst is the destruction of their natural habitat and pollution.