T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Turtle (Green) Chelonia mydas

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Cheloniidae
Subfamily: Cheloniinae
Genus: Chelonia
Species: C. mydas
Binomial name: Chelonia mydas
Common names: Green turtle, Black sea turtle, Pacific green turtle

Chelonia mydas is a large sea turtle whose range extends throughout tropical and subtropical seas around the world. 
Chelonia mydas is the commonest of the five species of turtles that visit New Zealand’s waters. The other four species are Caretta caretta (Loggerhead), Dermochelys coriacea (Leatherback), Dermochelys mydas (Hawksbill) and Lepidochelys olivacea (Olive ridley).
Some Green turtles spend a part of their life cycle around the north of the of the North Island, with individuals regularly seen in Tom Bowling Bay and Rangaunu Harbour and at the Poor Knights Islands. Though they are concentrated around the upper North Island, they have washed up on beaches as far south as Stewart Island.
The common name ‘Green turtle’ comes from the green, subdermal fat found beneath its round carapace (upper portion of the shell). Adults weight >130kg and have a body length of >1.2m. An adult carapace consists of four lateral overlapping scutes and it is an olive or brown with more or less distinct brown rays. The plastron (the lower shell) consists of four scutes and is yellowish white. Their tail is short. 
Green turtles have a hooked beak that covers the bones of the jaw. Their jaws are short and serrated to properly rip and tear plants apart. They are the only herbivorous turtle, feeding mostly on seagrasses, algae and mangroves. They also eat fish and their eggs, jellyfish, sponges and various shellfish.

Green sea turtles migrate long distances between feeding grounds and hatching on tropical beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and scramble into the water. Those that reach maturity may live to 80 years in the wild.
Green turtles are IUCN listed as Endangered (population decreasing). Coastal development and overharvesting by humans, propeller strike are thought to be the main causes of their decline. Some also die by ingesting plastic bags, as rubbish collects easily in the shallow harbours where they feed.
In New Zealand, sea turtles, are protected under the Wildlife Act 1953. This means it is illegal to kill or harass any species of sea turtle within New Zealand's Territorial Sea or Exclusive Economic Zone. It is also illegal to possess a sea turtle, or any part of a sea turtle without a permit issued under the Wildlife Act, or evidence that it was legally imported into New Zealand or was in your possession prior to the commencement of the Wildlife Act (1 April 1954).





The non-hooked beak.


Diagram of a green turtle

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/