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Loggerhead sea turtle
– Caretta caretta –

The loggerhead sea turtle is one of the seven living sea turtle species of the world, and counts among the most common representative of these animals in the waters of Madeira. Sea turtles travel with the currents (such as the Gulf Stream) to Madeira and the Azores from the coast of the Americas or the Cape Verde Islands, where they hatch. They spend the first part of their juvenile years there, and later return as adult, breeding animals to the beaches where they were born.

These animals spend almost their entire lives in the water. They are lung-breathing reptiles, and therefore have to come to the surface to breathe. They can stay under water for as long as 180 minutes. In the waters of Madeira, you can often see these animals basking on the surface. During basking, their shell is exposed to sunlight. It is assumed that the UV radiation in sunlight kills off algae and other creatures growing on their shells. The warmth of the sun also stimulates the metabolism (digestion) of the animals.

– General information –

Further names:
Deutsch: Unechte Karettschildkröte

Size of adult animals: Up to 1.2 m; weight of up to 180 kg.

Breeding: The sexes only meet during the breeding season. The females crawl out on a beach at night to lay their eggs in a deep pit that they dig with their flippers above the waterline. The eggs may number up to 120 depending on the age and condition of the female. When the eggs are successfully laid, the female buries them, and crawls back into the water. The young have to fend for themselves. There may be more than one clutch per season. Females usually lay eggs every two to three years. Juveniles hatch after 50 to 70 days depending on the ambient temperature. Right after hatching, they make their way into the water. Out of every 1,000 hatched juveniles, only one reaches the age of 20 to 30, when they become sexually mature. These animals can live for up to 50 years or longer.

Range: The tropical and subtropical oceans of the world.

Distinctive features: Their colour is reddish brown. Their bigger head, larger jaws and five instead of four pairs of rib plates distinguish them from the similar hawksbill sea turtle.

Behaviour and feeding: Young sea turtles are opportunistic feeders and eat everything that they can catch, but mainly jellyfish and other gelatinous animals. As they grow, their feeding habits change. Adult animals feed on crustaceans and mussels.

Taxonomy: Class: Reptilia (reptiles); Order: Testudines (turtles); Family: Cheloniidae (sea turtles)

Threats: They are endangered, and are on the Red List of Threatened Species. Their populations have declined drastically due to the collection of their eggs and being caught in fishing nets as bycatch. A lot of them also get entangled in trawling and drift nets, and floating debris (see the photos on Lobosonda’s Blog from 05/07/2010). The beaches where they lay their eggs are often taken over by tourists or are built on. The many artificial light-sources on developed beaches attract newly hatched animals, who are heading inland, instead of into the water, and are eaten by predators. Sea turtles are unable to distinguish floating plastic waste from their natural prey, the jellyfish. Again and again, they die after swallowing indigestible plastic bags.