What is unique about the nesting habits of alligators?

An alligator is a crocodilian in the genus "Alligator" of the family "Alligatoridae". The two extant species are the American alligator and the Chinese alligator. Additionally, several extinct species of alligators are known from fossil remains. Alligators are native to the United States, Mexico, and China only. The American alligator is quite bigger than the Chinese one.

American alligators live in freshwater environments, such as ponds, marshes, wetlands, rivers, lakes, swamps, and brackish water. In summer, the female builds a nest of vegetation where the decomposition of the vegetation provides the heat needed to incubate the eggs. This is the uniqueness of the nesting habits of alligators. The sex of the offspring is determined by the temperature in the nest and is fixed within 7 to 21 days from the start of incubation. Incubation temperatures of 30 °C (86 °F) or lower produce a clutch of females; those of 34 °C (93 °F) or higher produce entirely males. Nests constructed on leaves are hotter than those constructed on the wet marsh, so the former tend to produce males and the latter, females.