Let's Go Do Some Socializing My Family

Turtles are reptiles of the order Chelonii or Testudines characterised by a special bony or cartilaginous shell developed from their ribs and acting... more

by Tina M Wenger

Title

Let's Go Do Some Socializing My Family

Artist

Tina M Wenger

Medium

Photograph - Prints Of Photographs

Description

Turtles are reptiles of the order Chelonii or Testudines characterised by a special bony or cartilaginous shell developed from their ribs and acting as a shield. Turtle may refer to the chelonian order as a whole (American English) or to fresh-water and sea-dwelling chelonians (British English).
The order Chelonii or Testudines includes both extant (living) and extinct species. The earliest known turtles date from 220 million years ago, making turtles one of the oldest reptile groups and a more ancient group than lizards, snakes or crocodiles. Of the many species alive today, some are highly endangered.
Like all other extant reptiles, turtles are ectotherms�their internal temperature varies according to the ambient environment, commonly called cold-blooded. However, because of their high metabolic rate, leatherback sea turtles have a body temperature that is noticeably higher than that of the surrounding water.
Like other amniotes (reptiles, dinosaurs, birds, and mammals), they breathe air and do not lay eggs underwater, although many species live in or around water.
The word chelonian is popular among veterinarians, scientists, and conservationists working with these animals as a catch-all name for any member of the superorder Chelonia, which includes all turtles living and extinct, as well as their immediate ancestors.[citation needed] Chelonia is based on the Greek word kelone, for armour or interlocking shields."Turtle" may either refer to the order as a whole, or to particular turtles which make up a form taxon that is not monophyletic.
The meaning of the word turtle differs from region to region. In North America, any animal with a backbone and a shell made of bone is classified as a turtle in the order Testudines, including terrapins and tortoises. In Great Britain, the word turtle is used to describe marine shelled reptiles, but not tortoises.
In general use, the term tortoise usually refers to any non-swimming turtle, and scientifically tortoises are the Testudinidae family, only one of the 14 extant turtle families. Terrapin is used to describe several species of small, edible, hard-shell turtles, typically those found in brackish waters and is an Algonquian word for turtle.
Some languages do not have this problem, as all of these are referred to by the same name. For example, in Spanish, the word tortuga is used for turtles, tortoises, and terrapins, although the type they belong to is usually specified and added to the name, as marina for sea turtles, de r�o for freshwater species, and terrestre for tortoises.
Although many turtles spend large amounts of their lives underwater, all turtles and tortoises breathe air, and must surface at regular intervals to refill their lungs. They can also spend much or all of their lives on dry land. Aquatic respiration in Australian freshwater turtles is currently being studied. Some species have large cloacal cavities that are lined with many finger-like projections. These projections, called papillae, have a rich blood supply, and increase the surface area of the cloaca. The turtles can take up dissolved oxygen from the water using these papillae, in much the same way that fish use gills to respire.
In February 2011, the Tortoise and Freshwater Turtle Specialist Group published a report about the top 25 species of turtles most likely to become extinct, with a further 40 species at very high risk of becoming extinct. This list excludes sea turtles, however both the leatherback and the Kemp's ridley would make the top 25 list. The report is due to be updated in four years time allowing to follow the evolution of the list. Between 48 to 54% of all 328 of their species considered threatened, turtles and tortoises are at a much higher risk of extinction than many other vertebrates. Of the 263 species of freshwater and terrestrial turtles, 117 species are considered Threatened, 73 are either Endangered or Critically Endangered and 1 is Extinct. Of the 58 species belonging to the Testudinidae family, 33 species are Threatened, 18 are either Endangered or Critically Endangered, 1 is Extinct in the wild and 7 species are Extinct. 71% of all tortoise species are either gone or almost gone. Asian species are the most endangered, closely followed by the five endemic species from Madagascar. Turtles face many threats, including habitat destruction, harvesting for consumption, and the pet trade. The high extinction risk for Asian species is primarily due to the long-term unsustainable exploitation of turtles and tortoises for consumption and traditional Chinese medicine, and to a lesser extent for the international pet trade.
Efforts have been made by Chinese entrepreneurs to satisfy increasing demand for turtle meat as gourmet food and traditional medicine with farmed turtles, instead of wild-caught ones; according to a study published in 2007, over a thousand turtle farms operated in China. Turtle farms in Oklahoma and Louisiana raise turtles for export to China as well.

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October 14th, 2013