Both sexes become sexually mature when they are 6 to 7 feet, but full reproductive capacity is not realized until females are 7 feet and males are 8 feet long. Throughout most of their range, alligators begin courting in April and breed in late May and early June. Females lay a single clutch of 30 to 50 eggs in a mound of vegetation during early June to mid-July. Eggs incubate for about 65 days. In late August or early September, 9- to 10-inch hatchlings are liberated from the nest by the female. The female may defend and stay with her hatchlings for up to a year, gradually removing herself as caregiver as the breeding season approaches.
Alligator nests are about 2 feet in height and 5 feet in diameter. Nests are constructed of vegetation and materials in the surrounding habitat, which commonly includes cordgrass , sawgrass , cattail , giant reed , other marsh grasses, peat, pine needles, and soil. Females tend their nests and defend them against intruders, including humans.
Alligators are ectothermic, meaning they rely on external heat sources to maintain their body temperature. They are most active during warm weather (82o to 92o F), stop feeding when the ambient temperature drops below 70o F, and become dormant below 55o F.
Alligators are found in wetlands throughout the coastal plains of the southeastern US. They may be found in almost any fresh water habitat, but densities are greatest in wetlands that provide sites for nesting and feeding. In Texas, Louisiana, and South Carolina, the greatest densities are in highly productive coastal impoundments. In Florida, the highest densities occur in nutrient-enriched lakes and marshes. Coastal and inland marshes maintain the highest densities in Georgia, Alabama, and Mississippi. Alligators often inhabit urban wetlands, canals, lagoons, ponds, streams, and impoundments.
Alligators are exclusively carnivorous and prey on any animal that is available. Juvenile alligators (less than 4 feet) eat crustaceans, snails, and small fish. Sub-adults (4 to 6 feet) eat fish, crustaceans, small mammals, and birds. Adults (greater than 6 feet) eat fish, mammals, turtles, birds, and other alligators. Diet is dependent on where the alligator lives. In Louisiana coastal marshes, adult alligators primarily feed on nutria, whereas in Florida and northern Louisiana, rough fish and turtles comprise most of their diet. Studies in Florida and Louisiana indicate that cannibalism is common among alligators.