Crocodilians are extremely energy efficient. Because of this, they do not have to heat themselves using energy fueled by food as humans and other mammals do. Usually crocodilians need only eat once a week or less to maintain their energy levels. This behaviour is called gaping and it is done when the crocodile or alligator is basking in the sun. It is thought that this may act in cooling the crocodile, however, since they also do this during rain and at night it could suggest that gaping has a social function as well.
Crocodilians are well adapted to water, as well as land.
They are excellent swimmers and can hold their posture in water. When submerging underwater they close their ear and nostril flaps. When feeding underwater the back of the tongue acts as a valve to stop water from going into their lungs. Crocodiles and alligators can dive for long periods of time due to their slow metabolic rate. Vibration sensors and touch receptors help them to feel movements of prey in the water.