Siberian Tiger

Photo taken in Madrid Zoo. White Tiger - Panthera tigris tigris
The white tiger is not considered a tiger subspecies, but rather a mutant variant of the existing tiger subspecies. If a pure white Siberian tiger were to be born, it would therefore not be selectively bred within the tiger conservation programs. It would, however, probably still be selectively bred outside the program in an effort to create more white Siberian tigers. Due to the popularity of white tigers, they are used to attract visitors to zoos. - http://en.wikipedia.org/wiki/White_tiger