How does the sea turtle reproduce?

It’s very difficult to say exactly when a sea turtle reach sexual maturity. Not only does it vary among species, but even within the same species can it vary. Hawksbills can reach it after just 3 years, where it takes the Green Sea turtle 20-50 years to reach sexual maturity.

Studies have shown that sexual maturity often is related to carapace size. Despite what many believe a sea turtle cannot retract its head and flippers under its shell as a land turtle can. This makes of obvious vulnerable to attacks from sharks etc. when swimming in the sea.

For most species both male and females migrate, often thousands of kilometers, to special areas where the courtship takes place. This usually happens several weeks before the nesting season. The courtship places are often close or next to the nesting beaches.

Copulation takes place in the water and fertilization is internal. In the courtship period two or more males may court a single female. 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.

To help the males grasp on to shell of the females, they have enlarged claws on their front flippers. This goes for all species except the Leatherback.

A few weeks after mating the females come ashore on a sandy beach. She will usually come ashore at night. When possible she will come during high tide. She drags herself up on the beach till she finds a spot that?s suitable for a nest. First she?ll use her front flippers to dig out a ?body pit?. Then she uses her hind flippers to dig a cavity to the eggs. The depth of the cavity depends on the length of her flippers.

Depending on species she?ll deposit between 50 and 200 eggs in the cavity. The eggs are soft-shelled and surrounded by thick, clear mucus, so they don?t break when they fall down in the cavity. Then using her back flippers she?ll cover the nest with sand. When the nest is covered she?ll drag herself back to the sea again. From a female leave the sea till she returns she can spend two or more hours at the beach.

Depending on species a female will lay between one and five clutches of eggs in a season. Most of these will be laid on the same beach, but some females actually visits more than one nesting beach in a season.