Crocodiles have a mating process which is similar to that of all crocodillians (alligators, gharials). The actual coupling between an adult male and an adult female always takes place in the water and involves the internal fertilization of the female's eggs by the male's sperm. Crocodiles mate seasonally in early winter as this allows them to lay eggs in early spring.
A female crocodile will lay somewhere in the vicinity of 20 to 70 eggs. She lays these in a nest which she builds in the sand after first building several “trial” nests in order to find the perfect location. After laying, she will become very defensive of her nest, hissing, growling, and inflating her body in a display of warning to anyone who may come near. The father may also stand by and help defend the nest.
Curiously enough, the sex of crocodiles is determined, not by genetics, but by the temperature in the air during the middle third of their incubation period. For this reason, all of the hatchlings from one laying will be of the same sex. The temperature range for males is narrow, so more females are born.
Hatching and Early Life
When the offspring are about to hatch, they will make chirping noises. This is in indication to the mother that it is now time for her to remove the covering of the nest. Both mother and father by also help the eggs hatch by breaking the shells with their mouths. Once the babies are hatched, the mother will either lead them to water or carry them in her mouth. Mothers will protect their offspring for up to two years.