These tortoises, also known as elephant tortoises, live on seven islands. They are the largest living species of tortoise, with some specimens weighing up to 417 kilograms. Galapagos tortoises are among the longest-lived vertebrates, living more than 100 years in the wild (and up to 177 years in captivity). Their dorsal shell can be 150 centimeters long, and the largest individual found measured 1.87 meters.
It is likely that the tortoises of the Galapagos evolved from a common ancestor that was transported from the mainland by the Humboldt Current. Galapagos tortoises can swim, so it is likely that a fertilized female or pair of tortoises made their way from the mainland, perhaps on a floating platform made of tree branches.
It is very likely that the first tortoise swam to the island of San Cristobal and from there its descendants spread to the other islands of the archipelago. The original ancestor of the tortoises was probably of average size, and only the arrival in the Galapagos, where there were no natural enemies of the species, led to the development of gigantism. On each island, different subspecies evolved.
