The green turtles are the only herbivore among sea turtle species. They are so called because of the green coloured cartilage and fat and not because of the shell, which is often darker instead. Their diet, based on seagrasses and algae, is what gives their cartilage and fat a greenish colour. Their shell, instead is not green and can also be dark in some parts of the world, where they are called black turtles by the locals.
Similarly to other sea turtles, green turtles are known to travel incredibly long distances during their lifetimes. The two largest remaining nesting areas (in terms of numbers of nesting females) for green turtles are the Caribbean coast of Central America and the Great Barrier Reef in Australia. However they can be sighted in the Mediterranean Sea, where they are mainly found across the warmer eastern region and where they are known to have juvenile developmental grounds.
They are the largest hard-shelled sea turtles, with a length of about 90 to 120 cm and can weigh up to 160 kg. Their single pair of prefrontal scales make it easily distinguishable from the double pair in the loggerhead turtles.
Like all sea turtle species, they are threatened by human activities, such as by-catch, collisions, habitat degradation, hunting for meat consumption.