{"id":15912,"date":"2023-01-11T19:00:57","date_gmt":"2023-01-11T17:00:57","guid":{"rendered":"http:\/\/klqewmpxo.cyon.link\/?page_id=15912"},"modified":"2026-01-29T16:32:47","modified_gmt":"2026-01-29T14:32:47","slug":"unechte-karettschildkroete","status":"publish","type":"post","link":"https:\/\/azalas.de\/en\/loggerhead-sea-turtle\/","title":{"rendered":"The Loggerhead sea turtle"},"content":{"rendered":"

Guest contribution by Josef Platzek (text and photos by Josef Platzek)<\/h3>\n

T<\/big>he information used in this text comes primarily from the websites listed below, which belong to the Greek organisation for the Protection of Loggerhead sea turtles “Archelon”, the organisation
\n“Naxos Wildlife Protection” and the “Mediterranean Association to Save the Sea Turtles”.<\/p>\n

Sea turtles in Greece<\/h3>\n

O<\/big>f the seven species that exist worldwide, only three sea turtle species are regularly found in the Mediterranean: the Loggerhead sea turtle (Caretta caretta)<\/em>, the Green sea turtle (Chelonia mydas)<\/em> and the Leatherback sea turtle (Dermochelys coriacea)<\/em>. Of these species, only the Loggerhead sea turtle lays its eggs on Greek beaches. The most important nesting colonies are located on Zakynthos, the Peloponnese and Crete. The beaches of Zakynthos have especially large colonies, reaching one of the highest densities worldwide with up to 1,500 nests per kilometer.<\/p>\n

\"Loggerhead<\/a>
\nClick on the image to watch a video of the Loggerhead sea turtle (please wait a moment for the film to load!)<\/small><\/p>\n

Description<\/h3>\n

W<\/big>hile the Leatherback turtle, which is rarely found in the Mediterranean, is easy to recognise with its longitudinally ribbed shell, the Loggerhead turtle and the Green sea turtle cannot be distinguished at first glance. The species differ in the number of side plates (scutes) on the shell (5 or 4), the number of claws on the front feet (2 or 1) and the plates on the head in front of the forehead plate. When you meet a turtle while swimming or snorkelling, the side scutes and possibly the claws on the front feet are the identifying features easiest to see when you approach slowly.<\/p>\n

\"Loggerhead
\nDistinguishing features of the Loggerhead sea turtle: 5 pairs of scutes on the carapace and 2 claws on the front feet<\/small><\/p>\n

S<\/big>ince 2019, I have been studying the sea turtles of Naxos more intensively and documenting the animals with my camera. All the turtles I was able to clearly identify were Loggerhead sea turtles. Due to my holiday schedules, my contact with these fascinating animals has so far been limited to about 3 weeks in June and\/or September each year. During these periods, I was able to identify 3-5 individuals of Caretta<\/em> on the west coast in the Maragas\/Plaka beach area each year over the last four years, which could be clearly recognised by the patterns of barnacles, notches in their shells or special colouring of the scales on their front flippers, etc. The year 2021 was an exception: in June, I was able to identify 11 individuals in three weeks! I suspect this was an effect of the coronavirus lockdown, which led to a sharp reduction in tourism and fishing, resulting in less disturbance to the turtles and more frequent visits to the beach. In 2022, the number of sightings in June returned to the previous level with four individuals.<\/p>\n

Morphology<\/h3>\n

The shell<\/strong> is the most characteristic feature of all turtles. Consisting of a number of different bone plates, it forms an armoured casing for the soft vital organs. It consists mainly of two parts: the back shell or carapace forms the upper side and the so-called plastron forms the underside. Land and swamp turtles often have dome-shaped carapaces, which allow them to retract their heads and limbs into the protective shell. Sea turtles do not have this ability. In them, evolutionary processes have led to a more hydrodynamically shaped carapace.<\/p>\n

T<\/big>he shell of the Loggerhead sea turtle is heart-shaped and has five pairs of side or rib plates. The colour of the carapace is reddish-brown, but may be darkened by a coating of green algae. The plastron is pale yellow. The Loggerhead sea turtle can reach a carapace length of up to 120 cm and weigh up to 110 kg.<\/p>\n

I<\/big>n the course of evolution, the clumsy limbs of land tortoises have developed into the flat flippers<\/strong> of sea turtles. The front flippers are used for propulsion, while the rear flippers are used as rudders. While sea turtles can only move very slowly on land, they swim with fascinating elegance.<\/p>\n

\"Loggerhead<\/p>\n

Behaviour<\/h3>\n

S<\/big>ea turtles are perfectly adapted to their habitat, the sea. They find their food in the sea, migrate, rest and mate in the sea. Only the females come to land to dig their nests and lay their eggs. Males practically never go ashore. Little is known about the early years of sea turtles. After hatching, the young turtles crawl into the water and swim as fast as they can towards the open sea during their first few days, where they initially drift with the ocean currents. It is believed that they first feed on plankton, then on sea snails, tunicates (sea squirts, salps), barnacles and other organisms. After this pelagic phase in the open sea, Loggerhead sea turtles return to coastal waters.<\/p>\n

S<\/big>ea turtles breathe with lungs. This means that they need to surface at regular intervals to take a breath. Sea turtles are able to tolerate higher concentrations of carbon dioxide in their blood than most other air-breathing animals. In addition, their blood and muscle tissue can store large amounts of oxygen. These characteristics allow them to stay underwater for long periods of time. Sea turtles have been observed spending up to 6 hours sleeping underwater.<\/p>\n

S<\/big>ea turtles are not fast or agile enough to catch fast-moving prey. Their diet therefore consists mainly of slow-moving or sedentary organisms such as jellyfish, molluscs (snails, mussels), sea urchins, horseshoe crabs, sponges and seaweed. Turtles have been shown to have a well-developed sense of taste, which presumably helps them in their search for food.<\/p>\n

\"Loggerhead
\nLoggerhead turtle sitting on the seabed<\/small><\/p>\n

L<\/big>oggerhead sea turtles tagged in Greece have been found in waters off Italy, Tunisia and Libya, up to 1500 km away, suggesting deliberate migrations<\/strong>. Most recoveries come from the Gulf of Gabes in Tunisia and the northern Adriatic Sea, suggesting that the turtles from the Aegean spend the winter in these areas.<\/p>\n

Reproduction<\/h3>\n

T<\/big>he Loggerhead sea turtle only reproduces every 2-3 years. When they reach reproductive age (at around 16-28 years of age or when their shell length reaches around 70-80 cm), adult sea turtles migrate to their nesting sites. Mating has been observed during these migrations, but also in the coastal waters near the nesting beaches. The mating season is in April-May, with egg laying peaking in June-July. Of the specimens I have observed so far (approx. 25), an estimated 70-80% had reached the size and age required to begin reproducing. Among them were also some large specimens with carapace lengths of over one meter, which were certainly capable of reproduction and significantly older, as growth slows down considerably upon reaching sexual maturity.<\/p>\n

A<\/big>dult males have a longer, thicker tail with the cloaca opening further back than in females. During mating<\/strong>, the male mounts the female from behind and holds her carapace with his front limbs, with the hook-shaped enlarged upper claw on his front feet making it easier to hold on. The male’s longer tail bends downwards and presses the cloacal opening onto the female’s cloaca. There is also evidence that females can store the transferred sperm in their bodies for a longer period of time for future fertilisation of the eggs.<\/p>\n

\"Loggerhead<\/p>\n

\"Loggerhead
\nThe gender-specific morphological differences are clearly visible: above, a female with a rounded shell, short tail and straight upper claw on the front feet; below, a male with a longer, thick tail and large, hook-shaped upper claw on the front feet.<\/small><\/p>\n

F<\/big>or the laying of the eggs<\/strong> female sea turtles crawl far up onto sandy beaches to find a suitable place to make the nest. The female digs a pit about the size of her body by sweeping away the dry surface sand with her flipper-like limbs. Then, using their hind flippers alternately, they dig a jug- or pear-shaped hole, the egg chamber, into which the eggs are laid. During egg laying, the eyes secrete “tears”, a fluid from a special gland in the eyes. This fluid removes excess salt and also serves to keep the eyes moist and free of sand.<\/p>\n

T<\/big>he eggs of sea turtles are round with a leathery shell. Greek Loggerhead sea turtles lay a clutch of about 80-110 eggs every 3 weeks; they can lay eggs up to five times in one summer. In sea turtles, sex is not genetically determined, but is determined by the average incubation temperature: at higher temperatures, the eggs develop into females, at lower temperatures into males. In Caretta<\/em>, the so-called pivotal temperature, the incubation temperature at which equal numbers of males and females are produced, lies around 29 \u00b0C. Due to rising temperatures caused by climate change, 60% to over 90% of the young animals in Greek nesting sites are now female.<\/p>\n

A<\/big>fter 7 to 10 weeks, depending on the temperature of the sand, the young turtles hatch. As oxygen is scarce under the sand, it takes up to 4 days for the hatchlings to work their way to the surface. When they reach the upper layers of the sand, they pause during the day as the high temperatures make them drowsy. They wait just below the surface of the sand until it has cooled down at night or in the early morning, then they emerge in large numbers and quickly crawl towards the water, guided by the reflected moonlight or starlight. In Greece, a successful clutch produces about 35-50 hatchlings in the first hatching, followed by 2 to 3 smaller groups of 5-20 hatchlings over the next 2-10 days.<\/p>\n

Threats<\/h3>\n

T<\/big>he Loggerhead sea turtle is highly endangered in Europe and strictly protected. The greatest threats<\/strong> to the Loggerhead sea turtle in the Mediterranean are the increasing use of nesting beaches by tourists and accidental catches in fishing nets:<\/p>\n

Threats to the Loggerhead sea turtle posed by humans:<\/strong><\/p>\n

    \n
  1. Capture by fishermen for the meat, shell, etc.<\/li>\n
  2. Illegal collection of eggs for consumption<\/li>\n
  3. Bycatch in fishing gear and drowning or killing by fishermen<\/li>\n
  4. Dramatic decline and shrinkage of nesting beaches due to development and, above all, increasing tourist use<\/li>\n