White tigers are a color variant of the Bengal tiger, one of six surviving subspecies of tiger. White coloring is the result of a mutation in a single gene, which prevents expression of the normal orange color. The same mutated gene exists in horses and creates palomino and cream coloring.
White tigers can still have stripes because the mutant gene that prevents them from having reddish or yellowish coloring does not block the black pigment that forms the stripes. Stripes act as camouflage in
the tigers' natural habitats of forests, grasslands and swamps, helping them hide from the animals they hunt for food.
Reports of white tiger sightings in the wild date back as far as the 1500s. Records exist showing the animals lived in captivity as early as 1820 and have been popular zoo attractions for decades. Because of the demand for white tigers, some zoos have resorted to mating closely related animals, a practice called inbreeding. Inbreeding increases the chances of cubs inheriting the recessive gene for white coloring from both parents, but it also increases the chances that the cubs inherit genetic defects, such as kidney problems, clubbed feet and shortened tendons. The gene that causes white coloring is also associated with vision problems, such as crossed eyes and poor depth perception.