Green sea turtle – Chelonia mydas
The green sea turtle is a species in the family of sea turtles and therefore belongs to the order of testudines. Chelonia mydasa is also known as a black sea turtle or pacific green turtle and one of the most famous representatives of its family.
In the German-speaking world it is known as “Soup Turtle”, while in Mexico it is also called “Tortuga blanca”, which means white turtle. This is because it has many white spots, such as the breastplate and the seams between the back plates.
Description, Anatomy & Characteristics
The carapace of the green sea turtle is up to 140cm long, which gives it a weight of up to 185kg.
The back shell of Chelonia mydas has a bright basic colouring with green and brown to black patterns. The breastplate, on the other hand, is completely light yellow in colour. The extremities and the head are likewise of light appearance with dark brown to black pattern.
At the front flippers, black turtles have an extended claw.
Adult females are larger than males. In addition, they can be distinguished by the fact that the back armour of the male is tapered and the tail is longer.
Habitat, Distribution & Occurrence
The green sea turtle lives mostly in shallow coastal areas. These include seagrass meadows, coral reefs, sheltered bays and lagoons.
Chelonia mydas is rarely seen when scuba diving in the Canary Islands.
However, it can be found in all tropical and subtropical oceans and seas, including the Mediterranean Sea. The range of the turtle is limited only by the water temperature, which they avoid in waters with less than 7-10°C.
Feeding & Biology
While the young are carnivores and feed on cephalopods, fish eggs, molluscs, invertebrates, crustaceans and sponges, adult animals prefer a vegetarian diet. They like to graze algae and seagrass meadows.
The green sea turtle turns about 40-50 years old.
They sometimes cover long distances between their feeding and nesting grounds. Distances of 2600km are not uncommon. By their excellent magnetic sense they find the place of their birth again, at which they then lay their eggs.
With approximately 10-15 years, the green sea turtle reaches its sexually maturity. The mating takes place at the birthplace of the turtles. Both males and females are found on the respective beaches. Mating is controlled by the female, although in some populations a female may mate with several males.
After mating the females crawl ashore and bury their eggs above the tidal zone up to 50cm deep in the sand. This process takes 1-2 hours and is repeated 3-5 times during a mating period. A nest usually contains between 80 and 200 eggs. It takes about 50-70 days until the young green sea turtles hatch. The temperature determines the sex. At 28°C only males hatch and at 32°C only females.