Crocodiles reproduce by copulation. Copulation generally occurs in the water, and if fertilization occurs, the female crocodile will become pregnant and then lay her eggs.
Crocodile copulation doesn't happen until a somewhat complex courtship occurs. The male crocodile rubs its body against the female, and if she is receptive, she makes vocalizations so that he knows to proceed.
A female crocodile lays between 12 to 48 eggs in a nest after mating. Nile crocodiles dig a hole, then deposit the eggs and refill it with dirt. Saltwater crocodiles build a mound of dirt and plants to place their eggs in.
The eggs hatch after 2 to 3 months, when the crocodile young are fully developed.