Green Sea Turtle (Reptiles of Alabama)

Green Sea Turtle

Chelonia mydas

Summary ⁶

The green sea turtle (Chelonia mydas), also known as the green turtle, black (sea) turtle, or Pacific green turtle, is a large sea turtle of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans. The common name comes from the usually green fat found beneath its carapace.

Biology ⁷

Green turtles are long-lived and may take up to 59 years to reach sexual maturity (6) Undertaking tremendous feats of navigation, adults return to the same beach to breed each season, part of the population in Brazil astonishingly migrates around 2,250 kilometres across the open ocean to breed on the Ascension Islands (12). Mating tends to occur just offshore of the nesting beaches; using a curved claw on each front flipper and a flat nail at the end of the tail, males are able to grip their mates (2). Females haul out onto the beach at night and dig large nests with their back flippers beyond the high tide mark, they typically lay between 100 and 150 eggs in one nest and then proceed to cover the eggs with sand; the whole process takes around two hours (6). A single female returns to breed only once every two to five years but will lay up to nine nests in that one season (2). Incubation takes between 45 and 70 days, and temperature has been shown to determine of the sex of hatchlings; with females being produced at warmer temperatures (6). Breaking open their eggs with a special hooked 'egg tooth' that will subsequently be lost; hatchlings use their powerful front flippers to reach the surface, and then proceed to the sea (7). The soft-bodied juveniles are particularly vulnerable at this time from a variety of predators, such as ghost crabs and gulls on the beach to sharks and dolphins in the water (7). Unlike other marine turtles, adult green turtles are almost exclusively herbivorous, grazing on seagrasses and algae (8); it is assumed that juveniles are more omnivorous although the exact composition of their diet is unknown (6)