In summertime when the weather is warm, pregnant female sea turtles return to the beaches where they themselves hatched years before. They swim through the crashing surf and crawl up the beach searching for a nesting spot above the high water mark. Using her back flippers, the reptile digs a nest in the sand. Digging the nest and laying her eggs usually takes from one to three hours, after which the mother turtle slowly drags herself back to the ocean.

The sea turtle lays up to 100 eggs, which incubate in the warm sand for about 60 days. The temperature of the sand determines the genders of baby sea turtles, with cooler sand producing more males and warmer sand producing more females. The phenomenon is called Temperature-Dependent Sex Determination, or TSD, and governs the genders of other reptiles, too, including alligators and crocodiles. Current NOAA research suggests that warming trends due to climate change may cause a higher ratio of female sea turtles, potentially affecting genetic diversity.

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