A tortoise or land turtle is a land-dwelling reptile of the order Testudines. Like their aquatic cousins, the sea turtles, tortoises are shielded from predators by a shell. The top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The tortoise has both an endoskeleton and an exoskeleton. Tortoises can vary in size from a few centimetres to two meters. Tortoises tend to be diurnal animals with tendencies to be crepuscular depending on the ambient temperatures. They are generally reclusive and shy.
The first turtles already existed in the era of the
dinosaurs, some 200 million years ago. Turtles and tortoises are
the only surviving branch of the even more ancient clade
Anapsida, which includes groups such as the procolophonoids,
millerettids and pareiasaurs. Most of the anapsids became
extinct in the late Permian period, with the exception of the
procolophonoids and the precursors of the testudines (turtles
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.
Female tortoises dig and lay about a dozen eggs in burrows or
holes they dig. Hatchlings take approximately 90-120 days to
incubate from ping-pong-ball sized eggs. The hatchlings break
out of their shells with a front beak. Most hatchlings are born
with an embryonic egg sac, serving as a source of food for the
first couple of days. They are capable of eating solid food in
about 3-7 days. Unlike turtles, following birth the hatchlings
of most tortoise species will move from their nest and into
their mother's burrow. The mother will usually provide
protection for the hatchlings for around 80 days, after which
the babies will attempt to survive on their own.
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. 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.
Many, though not all, species of tortoises are sexually
dimorphic, though the differences between males and females vary
from species to species. In some species, males have a longer,
more protruding neck plate than their female counterparts, while
in others the claws are longer on the females. In most tortoise
species the female tends to be larger than the male. Some
believe that males grow quicker, while the female grows slower
but larger. The male also has a plastron that is curved inwards
to aid reproduction.
Most land based tortoises are herbivores, feeding on grazing grasses, weeds, leafy greens, flowers, and certain fruits. Their main diet consists of alfalfa, clover, dandelions, and leafy weeds, although they will also eat various insects. Feeding tortoises cat or dog food is a common mistake, as both cat and dog food contain too much protein and lack other important nutrients for tortoises. Tortoises are not carnivores, and should not be fed large amounts of protein, as it may cause shell deformation and other medical problems.
There is a large amount of speculation on the use of tortoise pellets, such as Mazuri Tortoise Diet, when feeding tortoises. Many of the pellets are horrible diets, but several, such as the Mazuri, make a great diet when added to a diet rich in fiber.
This Tortoise Page is Copyright The Animal Web Guide © 2004 - 2009 Chuck Ayoub