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Green Sea Turtle (Chelonia mydas)


Photos by J.D. Willson unless otherwise noted

 
species photo range map: SC and GA
 

Description: Green sea turtles have a carapace length of 88-125 cm (34.3-48.8 in) and weigh 113-204 kg (250-450 lb), making them the largest of the hard-shelled sea turtles. Males can be distinguished by their smaller size and longer, thicker tail. The carapace color ranges from light to dark olive brown and often has radiating mottled dark markings or large dark brown blotches. Each flipper of these sea turtles contains only one claw. In addition, there is a single pair of prefrontal plates between the eyes. Four costal scutes line each side of the carapace. The first costal scute does not touch the nuchal. Scutes do not overlap.

Distribution and Habitat: Greens can be found in shallow waters between 30° North and 30° South, although for the most part they nest in tropical waters. They sometimes travel thousands of miles between feeding and nesting grounds. In the Western Atlantic, the range of Green sea turtles extends from Massachusetts to Argentina. To prevent cold stunning, they migrate south in the winter. Greens occupy habitats such as marine grass flats and reefs with an abundance of seaweed and algae. Juveniles tend to remain in pelagic environments until 25-60 cm (9.8-23.4 in) of length, at which point they move closer to shore.

Reproduction and Development: Nesting season for Greens is year-round in the tropics and lasts from June-September in the southeastern United States. Nests are laid in open sand habitat, often on the female’s natal beach. It usually takes a Green sea turtle 2-3 hours to complete the nesting process, which involves body pitting, digging the egg chamber, and covering. The average clutch size is 110 eggs, and females typically nest 1-4 times per season, with an interval of 2 weeks between each nesting event. Incubation lasts for an average of 60 days. Warmer temperatures during incubation produce females, while cooler temperatures produce a greater number of males. Nesting is an exhausting process for female sea turtles, and most will only nest every 2-6 years.

Habits: Adult Greens are almost entirely herbivorous (aside from the occasional jellyfish and marine invertebrate). Juveniles, on the other hand, are primarily carnivorous. Seagrass, such as Thalassia testudinum, is a staple in the diet of Greens in the Caribbean and other areas, while Pacific populations eat large quantities of seaweed and algae. The name of these sea turtles relates to the color of their internal fat bodies, not to this largely herbivorous diet. Greens display the unique behavior of basking terrestrially, which is by far the most common occurrence of male sea turtles of any species coming to land. The predators of Green sea turtles are few, and consist of sharks and terrestrial mammals, including humans. Hatchlings are defenseless and can be eaten by a number of animals.

Conservation: Listed federally as an endangered species by the IUCN and CITES, Greens are threatened by habitat destruction and degradation on multiple fronts. Coastal development is a big factor in the loss of habitat, as is light pollution from streetlights and lights from nearby buildings. Water pollution destroys seagrass beds that are integral to the diet of Green sea turtles. Furthermore, Greens are considered to be the most palatable of all the sea turtles and are often harvested for their succulent meat and eggs. The use of Turtle Exclusion Devices (TEDs) is essential for the survival of this species.

Pertinent References:
Conant, R., and J. T. Collins. A Field Guide to Reptiles & Amphibians: Eastern and Central North America. 3rd ed. Boston: Houghton Mifflin, 1998.

Gulko, D., and K. Eckert. Sea Turtles: An Ecological Guide. Honolulu: Mutual, 2004.

Jensen, J. B., C. D. Camp, W. Gibbons, and M. J. Elliott. Amphibians and Reptiles of Georgia. Athens: University of Georgia, 2008.

Account Author: Lindsay Partymiller

 
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Turtles of SC and GA
Reptiles and Amphibians of SC and GA
SREL Herpetology