<P> In summer, the female builds a nest of vegetation where the decomposition of the vegetation provides the heat needed to incubate the eggs . The sex of the offspring is determined by the temperature in the nest and is fixed within seven to 21 days of the start of incubation . Incubation temperatures of 86 ° F (30 ° C) or lower produce a clutch of females; those of 93 ° F (34 ° C) or higher produce entirely males . Nests constructed on leaves are hotter than those constructed on wet marsh, so the former tend to produce males and the latter, females . The baby alligator's egg tooth helps it get out of its egg during hatching time . The natural sex ratio at hatching is five females to one male . Females hatched from eggs incubated at 86 ° F (30 ° C) weigh significantly more than males hatched from eggs incubated at 93 ° F (34 ° C). The mother defends the nest from predators and assists the hatchlings to water . She will provide protection to the young for about a year if they remain in the area . Adult alligators regularly cannibalize younger individuals, though estimates of the rate of cannibalism vary widely . In the past, immediately following the outlawing of alligator hunting, populations rebounded quickly due to the suppressed number of adults preying upon juveniles, increasing survival among the young alligators . </P> <Dl> <Dd> Alligators are similar to crocodiles and caimans; for their common characteristics and differences among them, see Crocodilia . </Dd> </Dl> <Dd> Alligators are similar to crocodiles and caimans; for their common characteristics and differences among them, see Crocodilia . </Dd> <P> Alligators, much like birds, have been shown to exhibit unidirectional movement of air through their lungs . Most other amniotes are believed to exhibit bidirectional, or tidal breathing . For a tidal breathing animal, such as a mammal, air flows into and out of the lungs through branching bronchi which terminate in small dead - end chambers called alveoli . As the alveoli represent dead - ends to flow, the inspired air must move back out the same way it came in . In contrast, air in alligator lungs makes a circuit, moving in only one direction through the parabronchi . The air first enters the outer branch, moves through the parabronchi, and exits the lung through the inner branch . Oxygen exchange takes place in extensive vasculature around the parabronchi . </P>

What type of water do crocodiles and alligators live in