Information about Tortoises

Tortoises
Aldabra Giant Tortoise (Geochelone gigantea) from Aldabra atoll in the Seychelles. Aldabra Giant Tortoise (Geochelone gigantea) from Aldabra atoll in the Seychelles.
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Testudines Suborder: Cryptodira Superfamily: Testudinoidea Family: Testudinidae
Genera
Chersina Cylindraspis (extinct) Dipsochelys Geochelone Gopherus Homopus Indotestudo Kinixys Malacochersus Manouria Psammobates Pyxis Testudo

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.

Evolution

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 and tortoises).

Biology

Birth

Female tortoises dig burrows in which they lay from two to twelve eggs. Hatchlings take approximately 90-120 days to incubate within the ping-pong-ball sized eggs. Upon completion of the incubation period the hatchlings break open egg shell enclosure with their beak and dig their way to the surface. Most hatchlings are born with an embryonic egg sac which serves as a source of food untill they are capable of eating solid foods, this stage lasts between 3 and 7 days. Unlike turtles, hatchlings of most tortoise species will move from their nest and into their mother's burrow following birth. The mother will usually provide protection for the hatchlings for around 80 days, after which the babies will attempt to survive on their own.

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, almost 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.^[1] The record for the longest-lived vertebrate is succeeded only by one other, a Koi Fish named "Hanako" whose death on July 17, 1977 ended a 226 year life span. [1]

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.^[2] 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.

Sexual dimorphism

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. The easiest way to determine the sex of a tortoise is to look at the tail. The females, as a general rule have a smaller tail which is dropped down whereas the males have a much longer tail which is usually pulled up and to the side of the rear shell.

Use in carrier bag production

Tortoise droppings have recently been used by EcoWorld Ltd in the development of ecologically friendly carrier bags; the chemical makeup of Tortoise feces shares the 1-4 hydrogen bond which is critical to the strength and durability of plastic, and by super heating it is possible to create a strong carrier which leaves virtually no carben footprint, and will decompose within two months of being buried.

Diet

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 when feeding tortoises as in fact, tortoise pellets contain way too much protein, which will cause shell deformation and other medical problems. As a general rule, tortoises kept as domestic pets (usually Testudo Graecae and Testudo Hermanae should be fed on weeds such as dandelions and clover and that is all that is needed. Calcium Carbonate can be ground into powder and added with weeds to provide extra essential calcium to a tortoise's diet.

Partial species list

• Chersina
• Chersina angulata, Bowsprit Tortoise
• Dipsochelys
• Dipsochelys abrupta (Extinct)
• Dipsochelys arnoldi, Arnold's Giant Tortoise,
• Dipsochelys daudinii (Extinct)
• Dipsochelys dussumieri, Aldabra Giant Tortoise
• Dipsochelys grandidieri (Extinct)
• Dipsochelys hololissa, Seychelles giant tortoise
• Furculachelys
• Furculachelys nabeulensis, Tunisian Spur-thigh Tortoise
• Geochelone
• Geochelone carbonaria, Red-Footed Tortoise
• Geochelone chilensis, Chaco Tortoise
• Geochelone denticulata, Yellow-Footed Tortoise
• Geochelone elegans, Indian Star Tortoise
• Geochelone nigra, Galápagos Giant Tortoise
• Geochelone pardalis, Leopard Tortoise
• Geochelone platynota, Burmese Star Tortoise
• Geochelone radiata, Radiated Tortoise
• Geochelone sulcata, African Spurred Tortoise (Sulcata Tortoise)
• Geochelone yniphora, Angulated Tortoise
• Gopherus
• Gopherus agassizii, Desert Tortoise
• Gopherus berlandieri, Texas Tortoise
• Gopherus flavomarginatus, Bolson Tortoise
• Gopherus polyphemus, Gopher Tortoise
• Homopus
• Homopus aerolatus, Parrot-Beaked Cape Tortoise
• Homopus boulengeri, Boulenger's Cape Tortoise
• Homopus femoralis, Karroo Cape Tortoise
• Homopus signatus, Speckled Cape Tortoise
• Homopus bergeri, Berger's Cape Tortoise
• Indotestudo
• Indotestudo elongata, Elongated Tortoise
• Indotestudo forsteni, Travancore Tortoise
• Kinixys
• Kinixys belliana, Bell's Hinge-Backed Tortoise
• Kinixys erosa, Serrated Hinge-Backed Tortoise
• Kinixys homeana, Home's Hinge-Backed Tortoise
• Kinixys natalensis, Natal Hinge-Backed Tortoise
• Kinixys spekii
• Malacochersus
• Malacochersus tornieri, Pancake Tortoise
• Manouria
• Manouria emys, Brown Tortoise (Mountain Tortoise)
• Manouria impressa, Impressed Tortoise
• Psammobates
• Psammobates geometricus, Geometric Tortoise
• Psammobates oculiferus, Serrated Star Tortoise
• Psammobates tentorius, African Tent Tortoise
• Pyxis
• Pyxis arachnoides, Madagascan Spider Tortoise
• Pyxis planicauda, Madagascan Flat-Tailed Tortoise
• Testudo
• Testudo atlas, Atlas tortoise, Colossochelys (Extinct)
• Testudo graeca, Greek Tortoise (Spur-Thighed Tortoise)
• Testudo hermanni, Herman's Tortoise
• Testudo horsfieldii, Russian Tortoise (Horsfield's Tortoise, or Central Asian Tortoise)
• Testudo kleinmanni, Egyptian Tortoise
• Testudo werneri, Negev Tortoise
• Testudo marginata, Marginated Tortoise
• Testudo tabulata, Jabuti

References

Further reading

• Chambers, Paul. A Sheltered Life: The Unexpected History of the Giant Tortoise. John Murray (Publishers), London. 2004. ISBN 0-7195-6528-6.
• Gerlach, Justin. Giant Tortoises of the Indian Ocean. Chimiara publishers, Frankfurt. 2004

External links

• Gulf Coast Turtle and Tortoise Society
• Tortoise World - Several Types of Tortoises
• Chelonia: Conservation and Care of Turtles.
• Infotortuga
• TortoiseForum.org: for all tortoise enthusiasts

Gallery

A baby Testudo marginata emerges from its shell	Testudo graeca ibera,Testudo hermanni boettgeri,Testudo hermanni hermanni,Testudo marginata sarda	A young (3.5 years) Sulcata Tortoise Geochelone sulcata	A young, 20 year old Tanzanian Leopard Tortoise feeding on grass
Aldabra Giant Tortoise Geochelone gigantea