Wiktionary
n. 1 Any member or species of the genus (taxlink Geochelone genus), land tortoises reaching 1.3 meters in length and with average life spans exceeding 100 years. 2 Any of several species of reptile of the extinct genera, (taxlink Cylindraspis genus), (taxlink Dipsochelys genus), and the species (taxlink Meiolania platyceps species).
WordNet
n. very large tortoises of the Galapagos and Seychelles islands
Wikipedia
Giant tortoises are characteristic reptiles that are found on two groups of tropical islands: the Aldabra Atoll in Seychelles and the Galapagos Islands in Ecuador (a population at the Mascarene Islands was exterminated by the 1900s) . These tortoises can weigh as much as and can grow to be long. Giant tortoises originally made their way to islands from the mainland; for example, Aldabra Atoll and Mascarenes giant tortoises are related to Madagascar tortoises while Galapagos giant tortoises are related to Ecuador mainland tortoises. This phenomenon of excessive growth is known as islands gigantism or insular gigantism. It occurs when the size of the animals that are isolated on an islands increases dramatically in comparison to their mainland relatives. This is due to several factors such as relaxed predation pressure, competitive release, or as an adaptation to increased environmental fluctuations on islands. These animals belong to an ancient group of reptiles, appearing about 250 million years ago. By the Upper Cretaceous, 70 or 80 million years ago, some had already become gigantic. About 1 million years ago tortoises reached the Galápagos Islands. Most of the gigantic species began to disappear about 100,000 years ago. Only 250 years ago there were at least 20 species and subspecies in islands of the Indian Ocean and 14 or 15 subspecies in the Galápagos Islands.
Usage examples of "giant tortoise".
For this was the end of May, the beginning of giant tortoise season.
Huge, squat, under a great bony dome of a shell, it looked like a giant tortoise&mdash.
Huge, squat, under a great bony dome of a shell, it looked like a giant tortoise—.
It was a giant tortoise, but it had four heads, spaced equally apart around the rim of its shell.
The world is really a flat plate supported on the back of a giant tortoise.
The procession passed through the gates, with the crowds dancing, singing and weeping with joy, filling the narrow streets so that the pace of the royal carriage was that of a giant tortoise.
Master )orian, we have a real treat for you: minced scarlet monkey from Beraoti, fried in the fat of the giant tortoise of Burang.
The viruses the Endangered Species Replacement Program used had been designed to replace, bit by bit, the genes that made a human being human with those that specified an anteater, a rhinoceros, a giant tortoise, a.
The Mock Turtle had the body of a giant tortoise, weighing perhaps six hundred pounds, and the head and back legs of a cow.
They haven't been out here to see for themselves that there isn't any giant elephant under the earth, holding it up, and a giant tortoise holding up the elephant, If I say 'planet' and 'spaceship' to them, they still think 'horoscope' and 'flying saucer.
Usually the royal falconer was vainly fighting off his hawks, who attacked him for a pastime, and in the case of King Henry kept picking him up and dropping him again in the belief that he was a giant tortoise.