In the southeastern U.S., mating occurs late March-early June. Lays 1-9 clutches (mostly 2-6) of about 45-200 eggs (average 120) at intervals of about 2 weeks, mostly every 2-3 years. Nests mainly at night, often at high tide. In the U.S., nests late April-early September, peak in June. Eggs hatch in about 7-11 weeks (generally 8-9 weeks in the southeastern U.S.). Egg mortality may result from predation, beach erosion, invasion of clutches by plant roots, crushing by off-road vehicles, or flooding by sea water overwash or excessive rainfall. Sex of hatchlings is affected by incubation temperature, with warmer temperatures resulting in a preponderance of females and cooler temperatures producing mainly or only males. Hatchlings emerge from nest a few days after hatching, typically during darkness. Sex ratio of hatchlings and immatures in Atlantic coastal waters of U.S. is strongly biased toward females (Wibbels et al. 1991, Mrosovsky and Provancha 1992). Females are sexually mature at an average age of about 15-30 years in the southeastern U.S. (but see Bjorndal and Bolten  for information on juvenile growth rates that suggests earlier age of maturity; see also Klinger and Misick, Copeia 1995:204-209, and Zug et al., Copeia 1995:484-487, for growth rate and age-at-maturity information). Females are reproductively active over a period of about 30 years (CSTC 1990). Nesting density reaches nearly 450 nests/km in some areas of Florida (Dodd 1992).