Green Turtle (Chelonia mydas)
Order: Chelonia, Family: Cheloniidae
Green turtles have a single pair of scales in front of their eyes rather than two pairs like other sea turtles have.
The green turtle is the largest hard-shelled sea turtle; adults commonly grow over 3 feet in length and weigh over 300 pounds.
Green turtles are outfitted with large, heart-shaped shells covered with horny plates. The shells are black, gray or brown (not green) — the green turtle gets its name from the green color of fat underneath its shell.
II. GEOGRAPHICAL RANGE AND HABITAT:
- Green turtles have a single pair of scales in front of their eyes rather than two pairs like other sea turtles have.
- The green turtle is the largest hard-shelled sea turtle; adults commonly grow over 3 feet in length and weigh over 300 pounds.
- Green turtles are outfitted with large, heart-shaped shells covered with horny plates. The shells are black, gray or brown (not green) — the green turtle gets its name from the green color of fat underneath its shell.
- Green turtles inhabit the Atlantic, Pacific and Indian oceans, as well as the Mediterranean and Black seas.
- They live in temperate and tropical waters, mainly near coastlines and around islands.
IV. LIFE CYCLE/SOCIAL STRUCTURE:
- Diet changes significantly throughout the green turtle's life span. During adolescence, green turtles usually eat worms, small crustaceans, insects, grasses and algae. Once they reach 8 to 10 inches in length, however, their diet changes, consisting of mostly sea grass and algae (green turtles are the only species of turtle besides the black turtle to be strictly herbivorous as adults).
V. SPECIAL NOTES/ADAPTATIONS:
- During mating season, the male green turtle will court the female by nuzzling her head or gently biting the back of her neck and rear flippers. If the female does not flee, he will attach himself to the back of her shell by gripping her top shell with the claws in his front flippers. He then folds his long tail under her shell to copulate. Sometimes several males will compete for the same female and may even fight.
- Females venture hundreds, even thousands, of nautical miles across seas and oceans, but always find their way back to their natal beach — the place where they incubated and hatched — to lay their eggs.
- Because of the green turtle's slow and awkward movement on land, nesting is exhausting work. It takes place every two to four years, two to eight times a season.
- To lay their eggs, females lumber ashore (usually at night) and select a nesting site above the high-tide mark. With their powerful hind flippers, they then dig a 12- to 18-inch-deep egg chamber, where they deposit between 40 and 90 eggs, covering them with sand before returning to sea (the process takes approximately one hour); two or three eggs drop out at a time.
- The average size of a clutch ranges from about 80 to 120 eggs. Because the eggs are flexible, they do not break as they fall into the chamber. This flexibility also allows both the female and the nest to hold more eggs.
- Incubation takes about 60 days; however, the temperature of the sand governs the speed at which the embryos develop. The hotter the sand surrounding the nest, the faster the development process. Evidently, cooler sand tends to produce more males, with warmer sand producing a higher ratio of females.
- Hatchlings break from their nest by themselves. To break open their shells, they use a temporary, sharp egg tooth (called a caruncle), which falls off soon after birth. Digging out of the nest is a group effort that can take several days. Hatchlings usually emerge from the nest at night or during a rainstorm, when temperatures are cooler. Once they decide to burst out, they erupt as a group. The hatchlings orient themselves to the brightest horizon, then dash toward the sea. If they don't reach the ocean quickly, they risk dying of dehydration or being eaten by predators, like birds and crabs.
- Obstacles for hatchlings in the open seas include sharks, big fish, circling birds, garbage and tar; only about one in 1,000 hatchlings survive.
- Green turtles live to be anywhere from 40 to 70 years old.
VI. POPULATION STATUS
- Green turtles have serrated lower jaws that enable to tear vegetation more easily.
- Nesting females appear to shed tears, but it is just a secretion of saltwater that accumulates in the body.
- The green turtle's ability to migrate hundreds of miles from its feeding ground to its nesting beach is considered one of the most remarkable acts in the animal kingdom.