There were originally fifteen different subspecies of Galapagos giant tortoise each evolved to suit the conditions on the different islands.

Credits

Image: Tortoise (Galapagos) by Daniel Ramirez

Information sourced from:

The IUCN Red List of Threatened Species (2015), Chelonoidis nigra [online],
Available from: http://www.iucnredlist.org/details/9011/0 [accessed 18/08/2015].