There are two populations of green sea turtles, the Atlantic and Pacific, which may be distinct species or simply subspecies. There are seven species of sea turtles alive today and with the exception of the Kemp's Ridley Sea Turtle and olive ridley, they are each the only species found in their genus. Leatherback Turtles are even found in a different family from the others – Dermochelyidae.
Green Sea Turtle
Green Sea Turtle
Scientific & Common Names
Kingdom - Animalia
Phylum - Chordata
Class - Reptilia
Order - Testudines
Suborder - Cryptodira
Family – Cheloniidae
Genus – Chelonia
Species – Chelonia mydas
Common Names: Green sea turtle, green turtle, black turtle
While their name would imply that they are green, their shells are actually tan to a dark mottled brown, depending on the area, although the skin can have a slight greenish hue. Their common name comes from the color of their fat, which they were once hunted for, along with their meat, skin, and shells. Unlike their freshwater cousins, sea turtles are unable to retract their head and limbs into their shells for protection. Green sea turtles are large turtles – second only to leatherbacks – and can reach sizes of five feet and 700 pounds, although 3-4 feet and 300-450 pounds is more common. While few individuals will survive to adulthood, those that do can live for over eighty years.
Sea turtles will migrate great distances during mating, which takes place every few years. Once mated, the females will find a suitable sandy beach, often the very same beach where they hatched, to lay their clutches of 100-200 eggs. The eggs incubate in the warm sand where their mother buried them for two months. Upon hatching, the young take the extremely perilous journey from the nest to the water. If the turtles are unfortunate enough to hatch during the day, their chance of survival decreases considerably since birds are added to the long list of predators feeding on the vulnerable hatchlings. Their best chance is as night, unless they are near a residential area with no nighttime light restrictions since they can become confused by the lights and move away from the water, guaranteeing they will not survive.
Once they have hatched, sea turtles rarely ever leave the water again. Mature females will haul up on beaches to lay their egg clutches a few times a year but males may never touch dry land again. Adult green sea turtles have been observed hauling out to sun themselves, but the behavior is rare. As juveniles, they have a relatively normal sea turtle diet of invertebrates but the adults become herbivores, unusual for sea turtles. As air breathers, turtles routinely stay submerged for only a few minutes, but they are able to remain underwater for hours while resting.
Sea turtles are reptiles and they have a long fossil history. Sea turtles became distinct from freshwater turtles over 100 million years ago, although they did have a terrestrial origin. As far back as the Jurassic period, fossil evidence shows turtles with marked similarity to modern sea turtles.
Like all sea turtles with the exception of Australian flatback (considered vulnerable), the green sea turtle is listed as either threatened or endangered, depending on the population, and the Mediterranean subspecies is listed as critically endangered. They are protected by many local and international laws, but adults and eggs are still poached. Some of the other threats they face are from development of their hatching grounds, marine debris, boat impact, and pollution.
Sea Turtles: A Complete Guide to Their Biology, Behavior, and Conservation by James R. Spotila
Biology of Sea Turtles, Vol. 2 by Peter L. Lutz, John A. Musick, and Jeanette Wyneken
Biology of Sea Turtles, Vol. 1 by Peter L. Lutz, John A. Musick
Wider Caribbean Sea Turtle Network (WIDECAST)
Sea Turtle Conservancy
Marine Conservation Biology: The Science of Maintaining the Sea's Biodiversity by Michael E. Soulé, Elliott A. Norse, Larry B. Crowder