Scientific classification: Turtles make up the order Testudines in the class Reptilia. Hidden-necked turtles make up the suborder Cryptodira, and side-necked turtles comprise the suborder Pleurodira.
Introduction
The Turtle is a reptile with a bony or leathery shell. Any shelled reptile can be called a turtle, but in North America people commonly use the word tortoise to designate members of a family of turtles that live entirely on land, reserving the word turtle for species that live in or near water. baby turtles, the word terrapin, of Native American origin, is used in North America only for the diamond-backed terrapin, a turtle that lives in the brackish waters of eastern coastal marshes.
Physical description
Turtles vary widely in size. The world’s largest turtle the great leatherback sea turtle reaches a shell length of 240 cm (96 in) and can weigh over 900 kg (2,000 lb). The giant tortoises of the Galápagos Islands, near South America, and the island of Aldabra, off the East African coast, can reach at least 130 cm (50 in) in length. The largest North American freshwater turtle is the alligator snapping turtle, which can reach a shell length of 80 cm (31.5 in). Among the smallest turtles are the American mud turtles and musk turtles, baby turtles which have a range that extends from southern Canada through much of South America. Many species in these groups are less than 13 cm (5 in) in shell length. Other small turtles are the rare bog turtle of the eastern United States, at 11 cm (4.5 in); and the tiny speckled cape tortoise of South Africa, whose shell is only 10 cm (4 in) long.
Life cycle and Reproduction
Female turtles have two ovaries organs that produce eggs and male turtles each have a pair of sperm-producing organs called testes. Male turtles, like male crocodiles, baby turtles have a penis that is located on the lower wall of the cloaca. The penis has a groove on its upper side. During mating, sperm travels along this groove and passes into the cloaca of the female.
Conservation
Many states and countries have passed laws to protect rare turtle species. More than 130 nations have signed a treaty called the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which regulates the international transport of endangered forms of wildlife, including many turtles and tortoises. Some countries, including the United States, baby turtles require large-scale shrimp fisheries to use nets that contain turtle excluder devices. These devices help turtles escape from fishing nets. Unfortunately, many wildlife laws are difficult to enforce, and developing nations in particular may lack the necessary resources for preventing the exploitation of turtles. Unless people around the world take steps to preserve turtles and tortoises within their natural environments, many species of these intriguing and ancient animals will probably become extinct during the 21st century.