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name for the dry-skinned, usually scaly, cold-blooded vertebrates (see Chordata) of the order Reptilia. Reptiles are found in a variety of habitats throughout the warm and temperate regions (except on some islands), with the greatest variety in the tropics.
..... Click the link for more information. of the order Chelonia, with strong, beaked, toothless jaws and, usually, an armorlike shell. The shell normally consists of bony plates overlaid with horny shields. The upper portion, or carapace, covers the turtle's back and sides, and the lower portion, or plastron, covers the belly; the two parts are joined at the sides. Exceptions are the rare plateless turtles of New Guinea and the marine leatherback turtle, which is encased in a thick, ossified skin resembling a carapace. When startled, most turtles withdraw their heads straight back into their shells, the neck folding into an S-shaped curve. However, in the side-necked turtlesside-necked turtle,
name for the long-necked turtle of the families Chelidae and Pelomedusidae, found only in the Southern Hemisphere. The neck in these two families is of a different structure from that of other turtles and is folded sideways under the shell for concealment
..... Click the link for more information. of the Southern Hemisphere, the head moves sideways and tucks next to the shoulder.
Turtles are found throughout most of the temperate and tropical world and in the open ocean; of the 270 known species, 42% are rare or threatened with extinction. Many turtles and their eggs are valued as food. Edible species include several marine turtles, the green turtle (traditional ingredient of turtle soup), the diamondback terrapin, and the soft-shelled turtles. Catching females when they lay eggs on land has contributed to a serious decline in many species, since it can take 10 to 30 years for some turtles to reach sexual maturity.
Different types of turtle are variously adapted to living on land, in freshwater, or in the ocean, but all turtles breathe by means of lungs (though some freshwater turtles also can absorb oxygen from the water through their skin or other means), and all lay eggs on land. The land-living species, especially those of the family Testudinidae, are commonly called tortoises. The name terrapin is generally applied to large freshwater or brackish water species, especially those used for food. Turtle species are either herbivorous or carnivorous but rarely both. They range in length from a few inches to over 6 ft (2 m), most being between 5 in. and 15 in. (13–38 cm) long. Many specimens have survived more than 50 years in captivity; one giant tortoise is known to have lived for 176 years, and another is believed to have lived about 250 years. Even larger giant turtles, some 8 ft (2.5 m) in length, lived c.3,000 years ago in the Pacific on Efate island, Vanuatu, dying out after the arrival of humans there. The largest known fossil turtle, Archelon ischyros, a sea turtle that lived during the late Cretaceous, was 15 ft (4.5 m) long.
Turtles existed 200 million years ago, at the time of the earliest dinosaurs; these early land-dwelling turtles could not retract their necks. By 120 million years ago some turtles had adapted to an aquatic life, although a 220-million-year-old ancestor of turtles that had only a bony breastplate may have been aquatic. Many of the living families of turtles existed in the Cretaceous period and have undergone very little change since then. On the basis of morphological (body structure) evidence, turtles were thought to be the oldest surviving group of reptiles. However, molecular studies comparing genes in different reptile groups indicate that turtles, along with crocodiles, are the most modern of reptiles.
Types of Turtles
Turtles are classified in 12 families. The Northern Hemisphere's largest family is that of common freshwater turtles (Emydidae), which includes about a third of all turtle species and is abundant in S and E Asia, E North America, and Central America. Members of this group have webbed feet; many spend most of the time in freshwater ponds or marshes; some live in brackish estuaries. They include such well-known North American turtles as the pond turtles (including the spotted, wood, and Muhlenberg's turtles), the painted turtle, the sliders, the diamondback terrapin, and the Blanding's turtle. The box turtlebox turtle,
hard-shelled land turtle of the genus Terrapene, native to North America. Its lower shell, or plastron, has a hinge dividing it into front and rear sections; the animal can raise these sections to meet the upper shell, or carapace, forming a secure box around
..... Click the link for more information. , which is primarily terrestrial, belongs to this family. Land tortoisestortoise
, common name for a terrestrial turtle, especially one of the family Testudinidae. Tortoises inhabit warm regions of all continents except Australia. They have club-shaped feet with reduced toes adapted for walking on land, and nearly all have high-domed shells.
..... Click the link for more information. (Testudinidae) form the second largest family. Tortoises have high-domed shells, move on club-shaped feet, are vegetarian, and live in warm regions throughout the world. The musk turtles and mud turtles (family Kinosternidae) are common small turtles of the E United States, and are found only in the Americas. The soft-shelled turtles (family Trionychidae) are flat-bodied, carnivorous freshwater turtles of the Northern Hemisphere, with a leathery covering instead of horny shields on their shells. The snapping turtlesnapping turtle,
large, aggressive New World freshwater turtle. The two snapping turtle species are the sole members of the family Chelydridae. Snapping turtles prefer quiet, muddy water. They spend most of their time submerged, surfacing periodically to breathe.
..... Click the link for more information. family (Chelydridae) is a North American group that includes the common snapper and the alligator snapper.
Marine turtles are classified in two families. The family Chelonidae includes five sea turtlesea turtle,
name for several species of large marine turtles found in tropical and subtropical oceans. These turtles are modified for life in the ocean by having flipperlike forelimbs without toes and lightweight shells. Their heads are too large to be withdrawn into the shell.
..... Click the link for more information. species of tropical and subtropical distribution: the green turtle, the loggerhead, the hawksbill (or tortoiseshell turtle), the Kemp's ridley, and the olive ridley. The family Dermochelidae includes only one species, the leatherbackleatherback,
marine turtle, Dermochelys coriacea, found in tropical, subtropical, and temperate waters around the world. The largest of all turtles, it may reach a length of 7 1-2 ft (230 cm) and weigh 1200 lb (540 kg).
..... Click the link for more information. , or leatherneck, largest and heaviest of all turtles, weighing as much as 1100 lbs (500 kg). Marine turtles lack toes, and their legs are oarlike, allowing speeds of nearly 20 mph (32 kph) in the water. With the exception of the loggerhead, all are endangered, either by pollution with plastic debris, which some turtles eat by mistake, or by commercial fishing, especially shrimp trawling. Commercial trade in all endangered sea turtles is banned; however, many wild turtles are skinned for leather and tortoiseshelltortoiseshell,
horny, translucent, mottled plates covering the carapace of the tropical hawksbill turtle. The plates, too thin for most purposes in their original form, are usually built up in layers that are molded or compressed after the surfaces have been liquefied by heat;
..... Click the link for more information. ornaments, or taken for food.
Turtles are classified in the phylum ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
..... Click the link for more information. , subphylum Vertebrata, class Reptilia, order Chelonia.
See C. H. Ernst and J. E. Lovich, Turtles of the United States and Canada (2d ed., 2009).
What does it mean when you dream about a turtle?
We associate turtles and their shells with their reputation for slowness and their protective coverings. So turtles in a dream could represent one’s emotional shell or one’s need to protect something. Alternatively, they could be representing some experience in which things seem to be going too slowly. But dream turtles could also be alluding to the tortoise who won the race against the hare because caution wins over haste.
Turtle(1) See Turtle Beach and Turtle Graphics.
(2) (Terse RDF Triple LanguagE) A variant of the N3 (Notation 3) syntax for writing RDF text. See RDF.