Facts and Knowledge:
Habitat: Several species of tortoise exist throughout the world, but the true giants are restricted to a few isolated tropical islands in the Pacific and Indian oceans. there are two species of giant tortoise: one is on the Galapagos islands, off the coast of Ecuador; the other is now restricted to the island of Aldabra, near Madagascar. Two species of giant tortoise on the Galapagos Islands have evolved to suit the vegetation. A raised carapace (upper shell) enables one species one species to feed on vegetation growing above ground level. This contrasts with the species of giant tortoise that lies in areas where there is more vegetation. This tortoise does not need to stretch above its head for food, so its dome shaped shell has not evolved with a raised carapace. The giant tortoise is a vulnerable animal, despite its armor. But the the giants have been able to flourish on their islands because they have no predators. In 1965 it was estimated that there were between 60,000 and 100,000 giant tortoise on Aldabra, over 10,000 per square mile.
Breeding The male giant turtle bobs his head and bellows loudly when he attempts to attract a mate. If the female accept s him, the male tortoise will mount her from behind. His under shell is hollowed out to accommodate her domed carapace, or upper shell. The female lays 10 to 20 rounds eggs and buries them in the sand or soil, where they incubate. the hatchling tortoise are no more then two inches long. On Aldabra many hatchlings are prey for robber crabs and frigate birds. On the Galapagos, introduced predators such as rats, cats, and dogs kill the hatchlings. After 18 months, young tortoises are still no larger than a mans fist. They grow steadily for 40 years before they reach full size.
Food & Feeding: The giant tortoise's diet consists mainly of vegetation, but it will eat almost anything. When food is plentiful during the rainy season, it can be more selective, favoring fresh young grass shoots and tender new leaves. Few shrubs on Aldabra have foliage within the reach of the tortoise, and few seedlings survive to maturity. The Aldabran tortoise float on the surface of the island's lagoon, reaching into the water with their long necks to feed on seaweed.. On the more Galapagos Islands, fresh grass and tender leaves are rare. Here, the tortoises feed on cactus, lichen, and even the acidic leaves of the guava tree. Very little food is available during the dry season. The tortoise survives for weeks on shriveled grass, dead leaves, and the remains of dead crabs, goats, and even the carrion (dead fish) of other tortoises.
Key Facts: Sizes, Weight, breeding, lifestyle,
Length: Up to 5 ft.
Height: Up to 600 lbs
Sexual Maturity: 30 to 30 years.
Mating Season: February to March
Incubation: 2 months
No of Eggs: 10 to 20
Habit: Generally solitary, but gathers to feed when food and water are scarce.
Diet: Grass and leaves, cactus, lichen, and carrion.
Life span: At least 100 years, possible 200.
Related Species: The two species of giant
tortoise, Geochelone gigantae and G. elephant opus, are not directly related
to each other. G. Gigantea relatives include the leopard tortoise,
G. pardalis, and the Indian Star tortoise, G. elegans.
Distribution: Pacific species, Geochelone elephant opus, lives on several islands of the Galapagos. The Indian Ocean species, G. gigantea, is now limited to the island of Aldabra.
Conservation: The Aldabran G. gigantea population flourishes and its future seems secure. The Galapagos population of G. elephant opus competes with introduced species and is endangered.
Features of Giant Tortoise:
Shell: The tortoises high convex shell provides defense against predators. The limbs can be drawn into the shell.
Legs: Tough scales cover the legs.
Feet: The tortoises feet are not webbed for swimming.
Pet Tortoise: This mediterranean tortoise grows to about 10 in...... It has spurred thighs.
The Specialized Shells: Two species on the Galapagos islands have evolved differently shaped shells, each adapting to the native vegetation.
Saddle backed Shell: Testudinoidae elepohantopus hoodensis: The shell is raised at the front, freeing the neck to reach higher vegetation.
Dome backed Shell: T. e elephant opus: Found where food is plentiful at ground level.
Did you know?
The giant tortoise can live for 200 years. An adult tortoise taken to Mauritius from the Seychelles in 1776 lived fro another 142 years, until 1918.
A tortoise's shell prevents it from expanding its chest, so it has special muscles to help it breathe.
The shell of a giant tortoise is surprisingly fragile. Its bone structure is very light, and the shell itself is easily damaged.