turtles usually nest at night, but there are some exceptions.
A female turtle arrives offshore at her beach, alone, at night.
She had mated earlier with a male turtle nearby in the water.
It is time to lay her eggs. She might nest three or four times
during a single nesting season. Though she is fast and well
suited to water, she is slow, awkward, and in danger on land.
The female drags herself out of the sea and onto the beach,
usually beyond the reach of high tide. The Leatherback
hauls herself forward by moving opposite limbs together. This
motion is also true of the green turtle. The Loggerhead, Hawksbill,
and both species of Ridleys move on land with a lizard-like
pait, in which diagonal limbs move simultaneously. Tracks
distinctive. As they leave the water and crawl up the beach
many dig their snouts into the sand, this may be a way of
remembering the smell and texture of the sand of the beach.
Once a nest has been chosen, the turtle
clears the area by sweeping with all four flippers.A body
pit is excavated by digging with front flippers, and rotating
the body. This removes dry sand that would collapse when dug.
The egg cavity is dug using the cupped rear flippers as shovels
to scoop out a bottle shaped hole. Sea turtles alternate their
hind flippers as they dig. After one rear flipper removes
a scoop of sand the other rear flipper shoots foward to spread
sand to the side and front preventing loose sand from falling
back into the egg cavity. The final depth of the egg cavity
is determined by the combined depth of the body cavity and
the length of the rear flippers. When her flippers can no
longer reach sand at the bottom of the cavity, she knows its
deep enough. Approximately 80-100 eggs are laid. They do not
break as they drop because the shells are leathery and flexible.
Leatherback's eggs are aout the size of golf balls. Very tiny
ones are infertile eggs. They have no yolks.
Two thirds of the time involved in nesting
takes place after the eggs have been laid. The female covers,
pushing sand. This is done until sand has been backed over
the eggs to the level of the beach. The leatherback uses both
front flippers to pull sand around her and over the nest site.
She also pivots her body, and with her weight to the rear,
continue to pack the sand. Lastly the body pit is filled,
the nesting site concealed with swipes of the front flippers
and swiveling movements of the rear flippers. Nesting completed,
tired and gasping, the turtle moves slowly back down the beach
to the surf and sea.
are not easily disturbed once egg laying has begun, but turtles
about to emerge from the water, ascending to the beach, or
digging a nest, will very often turn back or abandon a nest
if they are bothered by lights, loud noises or other unusual
activity, for example, being ringed by people when she is
blocked from sight of the sea (during digging), if she is
down-wind and can pick up the strong scent of people (emerging
and digging), or if people are standing too close to her.