Giant tortoises are found only near Tanzania and in the Galápagos. It is estimated a single pregnant tortoise floated from Africa to South America about 23 to 33 million years ago during the Oligocene period. Then, a Chelonoidis nigra ancestor followed the currents from South America to the Galápagos shortly after the first of the islands were formed about five million years ago. As the surrounding islands emerged, some tortoises migrated, began adapting to their new environments and evolved into different species.
