Galápagos tortoise, Giant Tortoise on Santa Cruz Island
Although often considered examples of island gigantism, prior to the arrival of Homo sapiens giant tortoises also occurred in non-island locales, as well as on a number of other, more accessible islands. During the Pleistocene, and mostly during the last 50,000 years, tortoises of the mainland of southern Asia North and South America, Australia Indonesia, Madagascar and even the island of Malta became extinct. The giant tortoises formerly of Africa died out somewhat earlier, during the late Pliocene. While the timing of the disappearances of various extinct giant tortoise species seems to correlate with the arrival of humans, direct evidence for human involvement in these extinctions is usually lacking; however, such evidence has been obtained in the case of Meiolania damelipi in Vanuatu. One interesting relic is the shell of an extinct giant tortoise found in a submerged sinkhole in Florida with a wooden spear piercing it, carbon dated to 12,000 years ago.
These animals belong to an ancient group of reptiles, appearing about 250 million years ago. In the Upper Cretaceous, 70 or 80 million years ago some already became gigantic. About 1 million years ago tortoises reached the Galápagos Islands. Since 100,000 years ago most of the gigantic species began to disappear. 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.