Turtles, Tortoise or Terrapin?

Although the word "turtle" is widely used to describe all members of the order Testudines, it is also common to see certain members described as terrapins, tortoises or sea turtles as well. Precisely how these alternative names are used, if at all, depends on the type of English being used.

• British English normally describes these reptiles as turtles if they live in the sea; terrapins if they live in fresh or brackish water; or tortoises if they live on land. However, there are exceptions to this where American or Australian common names are in wide use, as with the Fly River turtle.
• American English tends to use the word turtle for all species regardless of habitat, although tortoise may be used as a more precise term for any land-dwelling species. Oceanic species may be more specifically referred to as sea turtles. The name "terrapin" is strictly reserved for the brackish water diamondback terrapin, Malaclemys terrapin; the word terrapin in this case being derived from the Algonquian word for this animal.
• Australian English uses turtle for both the marine and freshwater species but tortoise for the terrestrial species.

To avoid confusion, the word chelonian is popular among veterinarians, scientists, and conservationists working with these animals as a catch-all name for any member of the order Testudines. It is based on the Greek word χελóνα( /çeˈlona/, chelone), meaning tortoise.

Lifespan

There are many old wives tales about the age of turtles and tortoises, one of which being that the age of a tortoise can be deducted by counting the number of concentric rings on its carapace, much like the cross-section of a tree. This is, of course, not true, since the growth of a tortoise depends highly on the access of food and water. A tortoise that has access to plenty of forage (or is regularly fed by its owner) will grow faster than a desert tortoise that goes days without eating.

Tortoises generally have lifespans comparable with those of human beings, and some individuals are known to have lived longer than 150 years. Because of this, they symbolize longevity in some cultures, such as China. The oldest tortoise ever recorded, indeed the oldest individual animal ever recorded, was Tui Malila, who was presented to the Tongan royal family by the British explorer Captain Cook shortly after its birth in 1777. Tui Malila remained in the care of the Tongan royal family until its death by natural causes on May 19, 1965. This means that upon its death, Tui Malila was 188 years old

The Alipore Zoo in India was the home to Adwaitya, which zoo officials claimed was the oldest living animal until its death on March 23, 2006. Adwaitya (sometimes spelled with two d's) was an Aldabra Giant Tortoise brought to India by Lord Wellesley who handed it over to the Alipur Zoological Gardens in 1875 when the zoo was set up. Zoo officials state they have documentation showing that Adwaitya was at least 130 years old, but claim that he was over 250 years old (although this has not been scientifically verified). Adwaitya was said to be the pet of Robert Clive 1.

Harriet, a resident at the Australia Zoo in Queensland, was apocryphally thought to have been brought to England by Charles Darwin aboard the Beagle. Harriet died on June 23, 2006, just shy of her 176th birthday.

Reference: http://en.wikipedia.org/wiki/Tortoise