The hawksbill sea turtle (Eretmochelys imbricata) is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus Eretmochelys. The species has a global distribution, that is largely limited to tropical and subtropical marine and estuary ecosystems. The hawksbill's appearance is similar to that of other marine turtles. In general, it has a flattened body shape, a protective carapace, and flipper-like limbs, adapted for swimming in the open ocean. E. imbricata is easily distinguished from other sea turtles by its sharp, curving beak with prominent tomium, and the saw-like appearance of its shell margins. Hawksbill shells slightly change colors, depending on water temperature. While this turtle lives part of its life in the open ocean, it spends more time in shallow lagoons and coral reefs. The World Conservation Union, primarily as a result of human fishing practices, classifies E. imbricata as critically endangered. Hawksbill shells were the primary source of tortoiseshell material used for decorative purposes. The Convention on International Trade in Endangered Species (CITES) regulates the international trade of hawksbill sea turtles and products derived from them. Taxonomy Linnaeus described the hawksbill sea turtle as Testudo imbricata in 1766, in the 12th edition of his Systema Naturae. In 1843, Austrian zoologist Leopold Fitzinger moved it into the genus Eretmochelys. In 1857, the species was temporarily misdescribed as Eretmochelys imbricata squamata. Neither the IUCN nor the United States Endangered Species Act assessment processes recognize any formal subspecies, but instead recognize one globally distributed species with populations, subpopulations, or regional management units. Fitzinger derived the genus name Eretmochelys from the Ancient Greek roots eretmo and chelys, corresponding to "oar" and "turtle", respectively, in reference to the turtles' oar-like front flippers. The species name imbricata is Latin, corresponding to the English term imbricate, in reference to the turtles' shingle-like, overlapping carapace scutes. Description Adult hawksbill sea turtles typically grow to in length, weighing around on average. The heaviest hawksbill ever captured weighed . The turtle's shell, or carapace, has an amber background patterned with an irregular combination of light and dark streaks, with predominantly black and mottled-brown colors radiating to the sides. Several characteristics of the hawksbill sea turtle distinguish it from other sea turtle species. Its elongated, tapered head ends in a beak-like mouth (from which its common name is derived), and its beak is more sharply pronounced and hooked than others. The