Behaviour of Marine Turtles

Nesting Behaviour

When a female has located the nesting beach she waits until night-time in waters close to the shore. Female turtles nest at night because it is cooler and in the darkness they are less conspicuous to large predators.
Even after dark, the female turtle constantly surveys the beach for danger whilst she crawls to the dry sand above the high tide mark. At this stage of the nesting process female turtles are easily scared away by bright lights and large moving objects.

Once she has found a suitable site she uses her front flippers in a swimming motion to scrape a large "body pit". She then carefully digs a precisely shaped "egg chamber" with her dexterous rear flippers. The dimensions of the nest and the number of eggs laid vary from species to species. On average the nests are about 50 cm deep and the female turtle will lay about 120 eggs per nest. The eggs of most species are about the size and shape as a table-tennis ball. The eggs of the Leatherback turtle are considerably larger. Turtle eggs have a soft shell and are not damaged as they drop into the nest. Sometimes, just to be sure, the female will guide the eggs down into the nest with a curved rear flipper.

Once egg lying is completed, she fills in the egg chamber with her hind flippers. Then she disguises the exact location of the nest by throwing sand behind her with her front flippers whilst gradually moving forward. The whole process of nesting can take as long as 3 hours, after which the female turtle returns to the ocean.