Alligators Crocodiles Caimans and Gharials: Crocodylia

Crocodilians are often night hunters and rest or sunbathe during the day. Unlike mammals that use their own energy to keep their bodies warm, crocodilians and other reptiles get their heat from their environment. One of the best ways to warm up is by sunbathing, also known as basking. Crocodilians may bask on dry land or along or just below the surface of the water. Some crocodilians, like gharials, are very careful when they bask on shore and will quickly retreat to the water if they feel the least bit nervous. Others, such as some large American alligators, will continue to bask even if approached quite closely. At a moment's notice, however, this peaceful-looking reptile can spring into action with a swipe of its powerful tail or a snap of its dangerous jaws. Most crocodilians are also quite fast and are actually able to outrun a person over a short distance.

Crocodilians move in several ways. All are excellent swimmers, usually gliding through the water by simply swaying the tail from side to side. Their tails are even strong enough to shoot their bodies several feet straight up and out of the water. On land, they often walk slowly, dragging the belly and tail on the ground. If they want, however, most can do a "high walk," in which they lift up the body to walk much as a lizard does.

Many species live together in groups and get along well for most of the year. During breeding season, however, the males get into arguments, wrestling matches, and sometimes more violent fights. They may bellow back and forth, push one another with their snouts, or bite each other. In some species, males try to attract the females by bellowing, or by rippling their back muscles so that water ripples over their scales. After mating, which occurs in the water, the females of all species lay their eggs out of the water. Some scrape leaves and often mud into a pile and lay their eggs in the pile, and others dig a hole as their nest. Depending on the species, a female may lay fewer than a dozen or many dozen eggs. As in some other reptiles, the temperature of the nest may control the sex of the young. In crocodilians, for example, a nest that is between 87.8 to 89.6°F (31 to 32°C) during a critical time not long before hatching produces mainly males, while an especially high or particularly low temperature during this period produces mainly females. The mother typically remains close by as the eggs develop, often chasing off raccoons or other animals that would dig up her nest and eat her eggs if given the chance.

When the eggs hatch, the mother helps her babies out of the nest and often to the water. Despite her toothy jaws, the mother can safely carry her babies either one or several at a time in her mouth. The young usually stay with their mother, and occasionally both parents, for a while. In most species, the young remain with the family for a few weeks or months, but in the American alligator, they may stay together for as long as two years. During this time, the female may provide protection to her young, may call to them when she finds food, or in some species, may actually chew a prey animal a bit, which helps her young tear off pieces to eat.