When a large male Nile crocodile spots a female that catches his eye, he bellows and splashes, slapping his snout on the water to get her attention. He grunts and growls, and sometimes, inhales as hard as he can, submerging his snout and blowing water through his nostrils, producing a fountainlike spray.

The female croc is ready to lay her eggs nearly two months after mating. She scouts the area for a suitable nest site in which to lay the eggs, usually digging a hole on a riverbank, shoreline, or dry streambed.

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She deposits from 25 to 80 eggs in the nest, then settles in for a long vigil. For a reptile, it's an unusual display of devotion. Other reptiles lay their eggs, then move on. The female croc, however, will keep constant guard over the nest during the three-month incubation period, leaving only to cool off in a nearby shady spot or for a quick dip in the water. The male is usually close by to help scare off predators.

Just before hatching, the young crocs send out high-pitched sounds—a signal for help. The female digs up the nest. The mother croc then carefully picks up the 12-inch-long (30.5-centimeter-long) hatchlings in her mouth and carries them to the water. The young crocs live under their mother's protection for up to two years, feeding on insects and small fish and growing about a foot (about 30 centimeters) each year.