The loggerhead turtle, Caretta caretta (Linnaeus, 1758) is the most common sea turtle in the Mediterranean Sea. The species is highly endangered throughout the Mediterranean basin and is now at the brink of extinction in Italian territorial waters.
They are animals that have adapted to aquatic life due to the elongated shape of the body covered by a sturdy shell and the presence of “legs” turned into fins. At birth it is about 5 cm long. The length of an adult specimen is of 80-140 cm, with variable mass between 100 and 160 kg.
The head is large, with very curved beak. The limbs are well developed, especially the front, and which have two nails in young individuals who are reduced to one in adults.
Has a carapace reddish brown, streaked with dark in young specimens, and a yellowish plastron, heart-shaped, often with large orange spots, with two prefrontal plates and a very strong horny beak. The dorsal shield of the carapace has five pairs of costal scutes; the single front shield brings five plaques. Side bridge between the carapace and plastron with three (rarely 4-7) shields inframarginal in contact with both the marginal shields with those of the plastron.
Young specimens often show a serrated dorsal hull that gives an appearance of “back-to-saw”. Males are distinguished from females by the long tail that grows with the attainment of sexual maturity, which occurs around 13 years. Even the nails of the front legs in the male are more developed than in the female.
Caretta caretta, as the majority of sea turtles, yet know very little. Like all reptiles, they are cold-blooded which leads them to prefer temperate waters. They breathe air, being equipped with lungs, but they are able to make long apneas. They spend most of their lives in the deep sea, returning occasionally to the surface to breathe. In water can reach speeds of over 35 km / h, swimming easily with the characteristic synchronous movement of the forelegs. They are omnivorous animals: they feed on mollusks, crustaceans, gastropods, echinoderms, fish and jellyfish, but in their stomachs were found everything from plastic bags, possibly mistaken for jellyfish, to caps and other plastic objects, mistaken for love fish, nets and wires mistaken for algae.
In summer, during the months of June, July and August, males and females are given conference in spawning areas, off the beaches where the latter are probably born. They have in fact an exceptional ability to find the source the beach, after migration where also travel thousands of kilometers. Some studies have shown that small newborn are capable of storing geomagnetic coordinates of the nest and other environmental features that allow an imprint of the source area.
Mating occurs in the water: the females mate with several males, collezionandone the seed for subsequent broods of the season; the male port on the back of the female and firmly clings to his armor, using nails a hook of the front legs, then folded her tail and contact her cloaca with that of the female. Copulation can last several days.
Occurred mating, the females await for a few days in warm, shallow waters for the right moment to lay eggs; in what are easily disturbed by the presence of people, animals, sounds and lights. Arrived, with some difficulty, on the beach will lay up to 200 eggs, the size of ping pong balls, placing them in deep holes dug with their hind legs. Then they cover them with care to ensure a constant incubation temperature and to hide their presence from predators. Once complete, they return to the sea. It is a ritual that can be repeated several times in the same season, at 10-20 day intervals.
The eggs have an incubation period between 42 and 65 days (there was a long period of 90 days, due to a late deposition that coincided with the soil cooler), and, through mechanisms not yet clarified, hatch almost all simultaneously; with substantial differences between the various substrates that form the beach where the deposition was made: the temperature and soil moisture, the grain size of the sand are determining factors for the success of hatching. The very wet soils often result in the loss of the eggs as many bacterial and fungal diseases can attack the eggs; also some beetles can reach the nest and parasitic. The temperature of the ground will determine the sex of the unborn: the eggs that are found on the surface are taking advantage of a thermal sum greater than those that lie deep, so the surface will give eggs female specimens and those male underlying.
The small to exit the shell using a particular structure, the “from egg tooth,” which it will then be reabsorbed in a couple of weeks. Hatched employ from two to seven days to dig the sand layer that surmounts the nest and reach the surface and then, usually with nightfall, head towards the sea. Under natural conditions they run quickly toward the sea. We can consider the small newborn as a sort of “robots” whose active biological program the automatic search of the light source in an arc of 15 degrees on the horizon. This is represented in normal marine horizon upon which the moon, and / or stars are reflected. But now the strong human determines a concentration of artificial lights that often bewilder the little newborn, causing them to deviate from the path, sometimes resulting in the loss of the entire brood.
Only a small proportion of infants succeeds in, often falling victim to predators, including humans; those that reach the sea, finally, only a fraction survives into adulthood.
Come to the sea swim non-stop for over 24 hours to get away from the coast and reaching the continental shelf, where the currents concentrate a large amount of nutrients.
Where exactly spend the first years of their lives is a mystery that biologists have not been able to explain the so-called “dark period”; only after a few years of life, reached sizes that put sheltered from predators, they return to coastal areas. Some observations, made in collaboration with the fishermen of the Ionian coast of Calabria, made it possible to survey several hundred trees almost the same age staying at a given point, in front of the lighthouse Capo Spartivento, where major currents meet in a quiet area: the of the turtles current border would pass several years before starting the great migration to other seas.
Distribution and habitat
The species and its subspecies, preferably reside in deep water and warm, next to the coast, the Atlantic Ocean, the Mediterranean and the Black Sea regions as well as the Indian Ocean and the Pacific Ocean. The largest concentrations of this animal found in South Africa, Florida, Australia, Mozambique and Oman.
In the Mediterranean Sea especially he frequents the waters of Italy, Greece, Turkey and Cyprus but also in Tunisia, Libya, Syria and Israel.