Females come ashore on a sandy beach to nest a few weeks after mating.
Female sea turtles must come ashore to build nests and lay their eggs.
- Females usually nest during the warmest months of the year. The exception is the leatherback turtle, which nests in fall and winter.
- Females of most species usually come ashore at night, alone, most often during high tide. A female sea turtle crawls above the high tide line and, using her front flippers, digs out a "body pit". Then using her hind flippers, she digs an egg cavity. The depth of the cavity is determined by the length of the stretched hind flipper.
- A female deposits 50 to 200 (depending on the species) Ping Pong ball shaped-eggs into the egg cavity. The eggs are soft-shelled, and are papery to leathery in texture. They do not break when they fall into the egg cavity. The eggs are surrounded by a thick, clear mucus.
Sea turtle eggs are soft-shelled and papery to leathery in texture. A female may deposit as many as 50 to 200 (depending upon species) Ping Pong ball-shaped eggs into the egg cavity that she digs in the sand.
- The female covers the nest with sand using her hind flippers. Burying the eggs serves three purposes: it helps protect the eggs from surface predators; it helps keep the soft, porous shells moist, thus protecting them from drying out; and it helps the eggs maintain proper temperature. Experts can identify the species of turtle by the type of mound left by the nesting female and by her flipper tracks in the sand.
- Females may spend two or more hours out of the water during the entire nesting process.
- It is possible that through the storage of sperm from one or several males in the oviducts of the females, all clutches of the current nesting season may be fertilized without repeated mating.