The sea turtles, Caretta caretta, are a carnivorous species and depending on the life stage they can also be omnivorous, feeding on a vast quantity of taxa and proving to be one of the most generalist among the few species of sea turtles.

This endangered species (Endangered in the IUCN Red List of Threatened Species) shows a dynamic life cycle depending on sex and age. Adult females come ashore to lay eggs and seem to prefer steeply sloped, high energy beaches. Juveniles are typically found among Sargassum mats drifting in warm ocean currents. Juveniles and older adults are most often found in coastal waters. They can also be seen near coral reefs or in conjunction with swamps, lagoons and at river mouths.

Caretta caretta is found in almost all temperate and tropical oceans of the world. During the winter months, sea turtles migrate to tropical and subtropical waters. Juveniles tend to disperse over a large area, crossing entire oceans such as the Atlantic and the Pacific. Although the Mediterranean Sea is small compared to the latter, it has a great variety of habitats that are useful to the plasticity of the life cycle of these organisms.

With large heads and powerful jaws, Caretta caretta turtles are the largest living hard-shelled sea turtles today. They have a heart-shaped carapace, which is often covered with commensal organisms such as barnacles and algae.

Unlike other marine organisms, and equally to other reptiles, the sex of sea turtles and the speed of development are determined by the exposure temperature during embryonic development, and more precisely by the temperature of the eggs during the middle third of incubation.

The temperature can be influenced by the sun, the shade, the weather conditions, the heat generated inside the nest and the respective position of the eggs inside the nest. At cool temperatures, around 25 ºC, it can take 65 to 70 days for hatching, but at warmer temperatures, around 35 ºC, development can usually take around 45 days.

The point at which a balanced sex ratio occurs is known as the pivotal temperature (the constant incubation temperature of eggs that will produce equal numbers of males and females. The pivotal temperature is a characteristic of TSD (Temperature-dependent Sex Determination)). Female sex is determined by warmer temperatures, while colder temperatures determine male sex.

The ratio between the sexes of the littles is obtained:

When they reach the youth stage, visible differences between the two sexes begin to emerge. In fact, males produce increasing levels of testosterone which, for example, leads to the lengthening of the tail. Females mostly produce estrogen with small amounts of testosterone becoming higher. The age of maturity is variable and ranges from 10 to 30 years.

Just before the nesting season, males migrate to mating grounds, usually off the nesting beaches, waiting for the females. A male will surround a female, then come up to her and bite her neck or shoulder. He will then attempt to mount her and, if she accepts it, they will mate. If a female does not accept the male, she covers her cloaca and swims to the bottom. A persistent male can wait until she needs air and will try to copulate another time. Males use the long, curved claws on their forelimbs to hold them back because mating can last for hours, and other males often bite the mating male, trying to remove it. If one male is removed, another can quickly replace him.

During the nesting season a female can lay several clutches and will mate again each time. In some cases, it can mate multiple times between clutches and therefore a single brood can have sperm supplied by several males.

The mating season for these specimens reaches its peak in the early summer months, in which the males stay off the nesting waters while the females mate, nest and try to feed. A female can nest every 12-17 days, or 2-5 times, during a breeding season.

Each time during nesting, the female must reach the mainland by dragging itself, evidently exposed to predation, and must dig a nest in the sand. In the latter, it will lay 110 to 130 eggs.

The energies spent by the parents towards the little ones are prior to the deposition, since there will be no parental care after it. Females are the ones that have a higher energy expenditure throughout the reproductive process since they provide nourishment in the form of yolk for the growth and development of the eggs. Furthermore, it is also necessary to consider the ovopositional process (nesting / laying of eggs) which certainly proves to be exhausting for these beautiful specimens. On the other hand, the male has only one form of investment, closely related to the act of copulation: sperm and the energy spent on sexual intercourse and courtship.

Caretta caretta sea turtles are migratory and have homing capabilities. Adults tend to return to the same nesting sites year after year, and many return to the beach where they were born.

It is estimated that around 150,000 sea turtles end up caught in fishing gear in the Mediterranean every year and that more than 40,000 of these die. Precisely for this reason there are many studies to generate more selective fishing tools. This is precisely the case of the Turtle Excluder Device which is a grid of bars with an opening at the top or bottom of the trawl. The grill is inserted into the neck of a shrimp trawl. Small animals pass through the bars and are caught in the end of the trawl bag. Larger animals, such as sea turtles and sharks, hit the grill bars and are ejected through the opening present.

In addition to accidental capture with fishing gear, ingestion of debris and pollutants, collision with boats and intentional killing, as well as plastic entanglement (which suffocates them), are other threats to this species.

Porto Cesareo in recent years is proving to be a potential nesting site used by the species. Thanks to the Marine Protected Area of ​​Porto Cesareo these new arrivals are monitored like sons, but nature must take its course.

In fact, the natural dangers for this species, and for all sea turtles in general, are more than we can imagine starting from sea birds and arriving at marine predation. In any case, as we said, to these threats are added those of anthropogenic origin.

The hatching of a nest of Caretta caretta turtles in that area occurred a few days ago and all I can say in this case is: good life, little ones!!

Maria Bruno