Giant Tortoise

Giant Tortoise, two huge endangered species of tortoise found on the Aldabra Atoll in the Indian Ocean and on the Galápagos Islands off the coast of Ecuador in the Pacific. Both the Aldabran tortoise and the Galápagos tortoise, the latter made famous by Charles Darwin, can reach lengths in excess of 1 m (3y ft) and weigh over 250 kg (551 lb). Reptiles of this size are likely to be very old, as growth is very slow; records exist of tortoises reaching 150 years of age. The tortoise is now rare because of human slaughter of the animals, the destruction of its habitat, and the introduction of animals that feed on the young tortoises and compete for food with the adults. During the 19th century in particular, giant tortoises were heavily hunted by sailors, as a source of fresh meat, both while visiting islands and to take away on long voyages. The tortoises have been known to survive as long as 14 months without food or water.

In the Galápagos the giant tortoises have evolved different shell, or carapace, shapes on the various islands. This is a result of variations in habitat and the plants they eat. On those islands with limited food resources, smaller tortoises have evolved. They have shells elevated above the neck and long legs which allow them to reach slightly higher vegetation. Two island forms are known to be extinct and a third is reduced to a single animal, “Lonesome George”, the only remaining tortoise from Isla Pinta, who now resides at the Charles Darwin Research Station. Hope for the survival of giant tortoises relies upon continued worldwide protection and the success of the captive breeding programme instigated over 20 years ago at the Darwin station. Female tortoises lay up to 17 eggs in a 30-cm (12-in) hole and the young dig out on their own. Many captive-born tortoises have already been returned to the wild.

Scientific classification: The giant tortoise belongs to the genus Geochelone in the family Testudinidae. The Aldabran tortoise is classified as Geochelone gigantea, the Galápagos species as Geochelone elephantopus (or sometimes G. nigra).