Download Chelonia mydas agassisi Galapagos Green Turtle

Colbi Brown
6/26/06
Expert Topic
Chelonia mydas agassisi Galapagos Green Turtle
The Galapagos Green Turtle is the most common species of turtle found on the
Galapagos Islands. It is thought to be an endemic subspecies of the Pacific Green Turtle.
It is the only turtle species to have been found breeding on the Islands. They are
commonly found in shallow lagoons around the islands, but can sometimes be found in
waters between the islands.
One of the most reliable places to spot these turtles is Black
Turtle Lagoon on the northern side of Santa Cruz. Many sea turtle species around the
world have become endangered, but in the Galapagos, the green sea turtle is still doing
well.
The Green Turtle is herbivorous, but little has been done to try and confirm their
eating habits. Mating usually takes place in November and December. These turtles are
not monogamous. It is common to see a mating pair with another male nearby waiting its
turn. Sometime between December and June, the females come ashore at night to lay
their eggs (males almost never leave the ocean). After excavating a large pit, they can lay
50-80 eggs at a time. The eggs are then buried and incubate for approximately 60 days.
The sex of the hatchlings is temperature dependent: over 30 degrees C the hatchlings
tend to be female, less than 30 degrees C, and the hatchlings tend to be male.
Both eggs and hatchlings are very susceptible to predation. While in the nest, the
eggs may be attacked by a beetle, Trox suberosus. They can also be dug up by pigs.
Once hatched, the hatchlings are prey of everything from ghost crabs to sharks. The
hatchlings normally emerge at night in order to avoid being easily spotted by frigate
birds. Hatchlings use the light reflected off the water from sky objects (stars, moon, etc.)
to find their way into the sea.
The Galapagos Green Turtle typically has a dark green to black shell, but it is
variable and can even have a yellow tortoiseshell color. The male is smaller than the
female. Adult Green Sea Turtles can grow to be 99 cm long and 180 kg. Studies of the
Galapagos Green Turtle have shown individually marked animals swimming many miles
away from the Galapagos, including the shores of mainland South and Central America
and in scattered locations in Costa Rica and Peru.
There are three other species of sea turtle found in the Galapagos: Hawksbill
Turtle (Eretmochelys imbricata bissa), Leatherback Turtle (Dermochelys coriacea), and
the Olive Ridley Turtle (Lepidochelys olivacea). The Hawksbill Turtle is notably smaller
than the Galapagos Green Turtle. It is regularly seen, but not extremely common. It is an
omnivorous turtle. The Leatherback Turtle is the largest in the world. Instead of a hard
bony carapace, it has tough leathery skin. It prefers the open ocean as compared to the
other turtle species. It feeds on jellyfish and other soft-bodied marine animals. The
Olive Ridley Turtle is the smallest found on the islands. It is found throughout the
tropics, but is not known to breed on the islands.
References
Fitter, Julian; Daniel Fitter; and David Hosking. Wildlife of The Galapagos. Princeton
University Press. Princeton: 2000.
Kricher, John. Galapagos. Smithsonian Institution Press. Washington: 2002.
MarineBio.org. “Green Sea Turtle.” June 26, 2006.