Green Sea Turtle
The green sea turtle (Chelonia mydas); is a large salt water turtle with a wide distribution throughout the tropical and subtropical regions of the world. One of the largest nesting areas is along the coasts of northern Australia. They get their name from the green fat located under their upper shell. While some sea turtles are omnivorous, green sea turtles are distinguished by their herbivorous nature. Green sea turtles are also known for making long ocean voyages from their nesting areas to feed. The International Union for Conservation of Nature and the Convention on International Trade in Endangered Species of Wild Fauna and Flora lists the green sea turtle as endangered, making it illegal to kill or otherwise harm adults, young, or eggs of the species. Australia has enacted additional specific laws for their protection.
The green sea turtle is of the family Cheloniidae in the order of Testudines. Their genus is Chelonia, and mydas is the only species in the genus. A major factor in listing them in a separate genus from other sea turtles is their herbivorous diet. When originally categorized in 1758, they were listed as Testudo mydas, but after additional research, they were assigned a completely new genus. Many languages use names for the green sea turtle that do not directly translate to the English name.
Green sea turtles have a flattened body useful in swimming in the open seas of the world. Most sea turtles share in a similar overall body structure. They have short necks and the foremost part of their head is beaked. Their beak is short and snub. The upper jaw is slighted denticulated, but the lower jaw is prominently serrated. The arms of the sea turtles are paddle-like and maximize the turtles’ ability to swim at speed and manoeuvre through water. The average body length of the green sea turtle is 1.5 metres, and the average weight is 200 kilograms. The largest green sea turtle on record was weighed at 395 kg.
The carapace, or shell, of the green sea turtle can vary in color. Sea turtles of the eastern Paccolourhave an exceptionally black carapace, whereas the green sea turtles of Australia are lighter in colour. Individual colours of the carapace can change over time. Juveniles can be coloured dark brown or olive. Mature turtles can be uniformly brown, or spotted with other colours, such as shades of red/orange and black. The underside of the green sea turtle is yellow, and the tops of their limbs and neck are darkly-coloured.
Pacific Ocean Populations
Green sea turtles are distributed throughout the Pacific from Alaska to Chile in the eastern Pacific, and from Russia to the northern coast of New Zealand in the western Pacific. Major Pacific populations are on the northern coast of Australia, Southeast Asia, Hawaii, and Mexico.
Green sea turtles are one of the most-studied species of sea turtle. Their ecology and habitat vary dramatically by their stage and cycle of life. Young hatchlings spend their first five years in the deep waters between the nesting area and feeding area. As they mature, they venture nearer the shore. It takes anywhere from 20 to 50 years before they reach sexual maturity. Mating takes place in the water, and when it is time to lay eggs, green sea turtles take to the sands of the shore. They then spend much of their lives in the coastal shallows where the seaweed beds are thick and can often be found in lagoon areas. Specific nesting areas and feeding areas can be used by families of green sea turtles for generations. The feeding area can be up to 2,600 kilometres from the nesting area. It is estimated that the total lifespan of the green sea turtle is up to 80 years.