There is a hypothesis (proven in several places for several species) called nest site fidelity, that states that sea turtles nest in the same beaches where they were born, traveling for hundreds to thousands of kilometers from their feeding grounds. This hypothesis helps explain the stability and permanence of colonies and populations of these organisms in a certain area.
It is speculated that ocean currents and temperature gradients might be a key factor in orientation, as well as the much accepted theory that turtles navigate using the magnetic fields of the earth. Sound also plays a significant role in their migrations, specifically when they reach mating areas due to the characteristic sound of waves of each nesting beach, determined by the sea floor structure (depth and inclination), the type of coast ,as well as the unique marine flora and fauna.
At the time of nesting, the turtles crawl up the sand looking for a place to nest on the beach; the mechanism by which they decide their spot to lay the eggs is not well understood, but it is known that it varies from one species to another and from one population to another. Once they pick the spot, they prepare the place by moving sand all around in what is called the body pit. After the turtle finishes the body pit, it starts digging the egg chamber with its hind limbs by alternating them, thus the depth and width are going to be determined not only by the species but by the size of the flippers as well.
After digging the egg chamber, the turtle lays its eggs one by one or in groups of up to 4 eggs at a time. The eggs are covered in a mucus lubricant that seems to have a bactericidal and fungicidal function. When finished, it covers the nest and tries to disguise it by throwing sand on top of it in a process called camouflaging. After the nest is covered the turtle returns to the sea.
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