The common turtle or loggerhead turtle, is the most common sea turtle in the Mediterranean Sea. The species is widespread in many seas of the world but is strongly threatened throughout the Mediterranean basin and is now on the verge of extinction in Italian territorial waters.

They are animals that have adapted to aquatic life thanks to the elongated shape of the body covered by a robust shell and the presence of "legs" transformed into fins. At birth it is about 5 cm long. The length of an adult specimen is 80 – 140 cm, with a mass varying between 100 and 160 kg. The head is large, with a very curved beak. The limbs are very developed, especially the fore ones, and equipped with two nails in the young individuals which are reduced to one in the adults.

It has a brown red carapace, dark streaked in the young specimens, and a yellowish, heart-shaped plastron, often with wide orange spots, equipped with two prefrontal plates and a very robust beak. The dorsal shield of the carapace is equipped with five pairs of rib scutes; the single front shield carries five plates. 

Young specimens often show a notched dorsal keel that gives it a "sawback" appearance. Males are distinguished from females by the long tail that develops with the achievement of sexual maturity, which occurs around the age of 13. The nails of the forelimbs in the male are also more developed than in the female.