Marine Animal Encyclopedia
Green Sea Turtle Chelonia mydas
The Green Turtle is the largest species in the family of hard-shelled sea turtles and second largest to the Leatherback Turtle among all sea turtles. Its common name comes not from the color of its skin or shell, which is common among most sea turtle species, but from the greenish color of its fat. The Green Turtle is the only sea turtle that is a strict herbivore, and its diet of seagrass and algae may contribute to the green fatty tissue.
Green Turtles are slow growing, long lived animals and do not reach sexual maturity until they are 20 years old. Like all sea turtles, Green Turtles spend almost all of their time in the ocean, and females typically come to shore only to lay eggs. For that reason, from the time they hatch and enter the surf, males will never be out of the water again and are therefore more difficult to study than females. After mating, females come to shore approximately five times during the course of the nesting season, dig a burrow, and lay more than 100 eggs each time. Much of scientists’ knowledge of these turtles is a result of studying the females when they come ashore. After several weeks, the baby Green Turtles hatch and enter the water together to begin their journey toward adulthood. Though this behavior of coming to shore only to nest is typical around the world, there is at least one population of Green Turtles (in Maui, Hawaii) that includes some individuals that are known to climb on beaches during the day, to rest in the sun.
Green Turtles are known to travel incredibly long distances during their lifetimes. In some cases, individuals may travel across entire ocean basins, after they hatch, in order to reach juvenile feeding grounds. Throughout its lifetime, a Green Turtle may cross the ocean several times, traveling to and from preferred feeding or nesting sites. Like other marine turtles, Green Turtles return to the same beach where they hatched to nest. 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.
The Green Turtle is an endangered species (= it is highly vulnerable to extinction). The most predominant threats to this species occur on nesting beaches. Coastal development has reduced the area where they can successfully nest, dogs and other animals often destroy their nests, and people harvest their eggs for food. Hunting of adults for food also still occurs in many places. Individuals are either captured at sea or taken from their nesting beaches. Finally, thousands of Green Turtles are accidentally captured in fishing operations targeting other species. All of these threats have combined to drive Green Turtle populations to dangerously low levels. Naturally, only one or two of thousands of eggs will make it to adulthood. These added anthropogenic pressures make the chance of survival even worse. Many countries around the world offer Green Turtles some or complete legal protection, but even in those places, threats to their nesting beaches persist. Legal measures often extend to turtle nests but rarely extend to the beaches themselves, so alteration of natural habitat continues to threaten this and other marine turtles.