Giant Tortoise No animal is more synonymous with the Galapagos Islands than the giant tortoise. Indeed, the saddle-back shape of the shell in many of the tortoise races reminded the early Spaniards of a type of riding saddle called "galapago", and this term is also applied to the tortoises. Hence, by calling the islands the Galapagos, we are, in essence, calling them "The Islands of the Giant Tortoises"!, The giant tortoise is the symbol of both the Charles Darwin Research Station and the Galapagos National Park Service. In the form of one particular individual, Lonesome George, the sole surviving member of the Pinta Island race, the giant tortoise is the symbol of extreme fragility of the Galapagos islands, and a reminder of the need for vigilence and conservation. It was also the giant tortoise that tipped Darwin off to the incredible diversity of the Galapagos fauna and flora. In the "Voyage of the Beagle. There are 15 recognized races of tortoise, all generally considered to be members of the single species Geochelone elephantopus.. The genus Geochelone itself is represented by a cluster of species of small to medium-sized tortoises in South America, Africa, Madagascar, and Asia. In the past, giant species of Geochelone were once found on all continents except Australasia, but today the giant forms are restricted to G. elephantopus in the Galapagos and G. gigantea on the island of Aldabara. There are a number of captive G. elephantopus populations in zoos around the world and it seems that fertility is lower in those zoos that permit breeding between members of different races. The reasons for this reduced fertility are unclear, but it is not possible at this point to rule out genetic factors. The basic definition of the term "species" includes reproductive incompatibility with other species. If this reduced fertility does indeed turn out to be genetic, then the the degree of relatedness between the 15 Galapagos races and their taxonomic status become unclear. Of the 15 races of Galapagos tortoises, four are extinct. Because of breeding and release efforts on the part of the Charles Darwin Research Station, most of the remaining races are holding their own. However, there is still on-going poaching of tortoises by local residents. One race, that from Pinta is represented by a single surviving male, aptly named Lonesome George. The 15 races are: Genus species / race Island Geochelone elephantopus Floreana (extinct) not described Santa Fe (extinct) Phantastica Fernandina (extinct) Wallacei Rabida (extinct) Hoodensis Espanola Abingdoni Pinta Ephippium Pinzon Chatamensis San Cristobal Darwini Santiago Vicina Volcan Cerro Azul, Isabela Guntheri "" Sierra Negra, Isabela microphyes "" Darwin, Isabela Vandenburghi Volcan Alcedo,Isabela Becki Volcan Wolf, Isabela Porteri Santa Cruz