Loggerhead Turtles that Nest on Kiawah's Beach

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Turtle Tales

Many of my stories concern marine turtles called Loggerheads. I feel that it is essential to describe for the reader as briefly as possible the nature of this animal so that you will appreciate the efforts of volunteers on Kiawah Island to protect these turtles during their nesting.

Five species of marine turtles, the Green, Hawksbill, Kemp's ridley, Leatherback and Loggerhead, pass by our shore, but only the Loggerhead nests along the South Caarolina coast in large numbers. The Loggerheads (Caretta, caretta, to give the species its definitive scientific name) are of an ancient lineage, because their ancestors go back more than 150 million years.

Today, their ancient lifestyle is threatened by human activities all over the world. The genetic traits and behavioral patterns that they developed over those vast periods of time made their survival possible. However, those traits are not flexible enough to permit them to adapt to the swift and drastic changes inflected upon their habitat by the recent arrival of man.

Therefore, many of us feel impelled to do what we can to insure that they continue to survive and share with us this beautiful world they have known so very long.

When the water warms on the continental shelf in spring, male and female turtles assemble to mate. After the mating period, the male departs but the female remains offshore while her fertilized eggs develop.

Sometime in May, she lumbers ashore at night and begins the laborious struggle up the beach to a nesting site. She is wary at this time and easily frightened off by a noise or a carelessly shown flashlight; that is one reason for the motto, "Lights out for turtles".

Once she has selected a site, she slowly digs her nest with her back flippers, alternating one and then the other to withdraw a scoop of sand until she reaches the maximum depth, about 18 inches beneath the surface. She begins to deposit her eggs one at a time, and these fall to the bottom of the nest and pack together.

When the last of the 100 150 eggs have been deposited, she tops off the nest with sand, packs it down firmly by thumping her shell over it and throws sand all around the area with her flippers for concealment. Down the beach and into the waves she goes, never to return to the nest. She has done her part; now it is up to the next generation.

What happens in the nest she has left behind? If she has chosen a safe site, the eggs begin to develop. Each egg is remarkably like a Ping-Pong ball in appearance. It is round, white and covered with a parchment like, pliable shell. The dark, moist nest cavity beneath the sand maintains a constant temperature day and night; therefore, it is a nearly ideal incubation chamber.

The embryo develops over a period of about 55-60 days into a tiny turtle, all curled up within the shell. It grows a sharp spine on the tip of its snout called an egg tooth, and with that tooth it ruptures the shell and is able to leave the egg. Resting, sometimes for days within the nest cavity, it straightens its body and continues to consume the remnant of the attached yolk sac.

Then, restless stirring within the compact mass of little turtles activates them all, and they cooperatively struggle up through the sand to within perhaps a few inches of the surface. There they pause and wait again. What are they waiting for?

They wait for the best time to leave the nest and make a dash for the ocean; that time is after nightfall when few predators are around, or least likely to see them. They seem to sense that time by the drop in temperature of the surface sand as the sun drops below the horizon.

Then out they come in a rush and head for the water. Once there, they instantly change from a crawling gait to a swimming stroke and off they go as rapidly as possible. Here too the predators wait, because they are a welcome morsel for fish and crabs beneath the surface, and for gulls and other birds above.

For a long time, it was a mystery where they went. Now we are beginning to understand that they swim away from land in a frenzy until they encounter masses of sargassum and other seaweeds in the Gulf Stream possibly 20 or 30 kilometers offshore.

Here in the shelter of the weeds, they remain and grow for an indeterminate length of time. Finally they voyage out on their own into the vast ocean.

After a period of 20 25 years, the survivors (possibly as few as one in ten thousand!) will gather off our coast to mate and nest. Hopefully they will receive a friendly and protective reception at that time from our children and grandchildren.

 

 

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