Reaching sexual maturity at 2.5 m, females prepare nests during the dry season either in holes or on mounds of mud or sand (3). After two months of surprisingly gentle courtship, during which the female must reduce the male's territorial aggression by making audible signals and by lifting her head to expose her throat, and nuzzling his head and neck (6), the female lays between 30 and 60 eggs. These are covered with sand and left to incubate under the heat of the sun for 90 days (3). The female guards the nest and assists during the hatching process, which coincides with the start of the annual rains. Both parents may guard the hatchlings (6) although they can fend for themselves immediately (2). Only a few survive due to predation particularly by raccoons (7). Adults make dens, dug 3 – 9 m into the river bank, near their nest site, but move inland during the winter, as they are unable to tolerate water temperatures of much below 18 ºC (6). The American crocodile's diet consists mainly of fish, but birds, small mammals, crabs and turtles are also taken and eaten underwater (3). Crocodiles hunt by waiting motionless in the water until their prey is close enough, then attacking the prey and drowning it. They will even regurgitate small amounts of food to attract fish. During winter, the digestion rate is very slow, so they can go for months without food (2).