If you ask a group of people what their favorite animal is, chances are at least some of them will answer “white tigers”. In fact many people seem to think of white tigers as fundamentally different from orange tigers, while in reality the only major difference is their coloration as determined by genetics [1].
While orange is by far the most commonly found tiger coloration in the wild, other color variants such as white, golden and stripe-less snow white are theoretically possible to find also in wild population but have very rarely been reported [2,3]. However, these color variations have become great favorites with the general public, and have consequently been bred extensively and aggressively with color as the only breeding goal. With such an arbitrary trait as the only desired outcome of a breeding program, it is almost impossible not to breed problems. In general, a breeding program for any animal species should include a wide range of factors, animal welfare and health being among the most important. If these factors aren’t taken into consideration in the breeding program, then poor health and welfare are likely outcomes.
This is very much the case in the breeding of rare tiger color variants. In order to consistently produce animals that fit what the public wants, inbreeding and heavy breeding of certain individuals have become common. While some degree of inbreeding can be acceptable in certain populations, this type of extreme trait breeding overlooks the rising occurrences of health issues such as strabismus, scoliosis, hip dysplasia and organ failure [4,5,6].
The degree of inbreeding in white tigers is so severe it is hard to even fathom. In fact, on single white male tiger, Mohan, captured in India in 1951, after being bred with his daughter, gave rise to the entire first generation of captive bred tigers. Different granddaughters of this coupling then produced separate lines of white tigers through the National Zoo in Washington DC and through what is referred to as the Cincinnati white tiger line. Many of these tigers were also produced breeding brothers to sisters. Both of these bloodlines have now died out in the US, and the only white tiger line left is a result of a male crossbreed (half Amur, half Bengal), bred to a white color gene-carrying female Bengal. In other words, these tigers are all hybrids [7].
In order to justify their breeding of the rare color variations, some facilities promote their production as conservations. While you could argue that the conservation of different aesthetics is also conservation, these tigers have no value in a real world conservation scenario. Not only are captive bred tigers generally not released into the wild, a tiger with multiple and severe health issues will also not be of value in potential global insemination programs or genetic diversity programs.
A further indication that the breeding of white tigers or other rare color variations is an unhealthy practice, is the official stance of the Association of Zoos and Aquariums (AZA). AZA has in a white paper dated in July 2011 [8] barred all member zoos from intentionally breeding white tigers, along with exotic color variations in other species. The white paper argues that alleles responsible for such color variation should not be selected for, but should be maintained at the frequency they are found in wild population. In this way, the organization hopes to maintain a higher level of genetic diversity in populations as well as producing fewer congenital defects as a result of breeding for these traits.
For Tigers very much shares the view of AZA in the case of breeding for aesthetic traits. We also suggest avoiding facilities that actively breed such color variations, as well as hybrids such as ligers. If you are unsure whether a facility actively breeds these animals or whether they are simply housing them, we suggest contacting the facility directly or talking to NGOs or Zoo organizations in the country in question.
References
Xu, X., Dong, GX., Schmidt-Küntzel, A. et al. (2017). The genetics of tiger pelage color variations. Cell Res 27, 954–957.
Zebley, M., Olson, T., & Ito, S. (1997). The genetic and biochemical basis for the “golden tabby” and “snow white” Bengal tigers. Annual Proceedings-American Association of Zoo Veterinarians: Hill's Division, Riviana Foods, 78.,
Sankhala, K. (1997). Tiger! The Story Of The Indian Tiger. Simon and Schuster. ISBN 978-0-00-216124-4.
Kingston HM (April 1989). "ABC of clinical genetics. Genetics of common disorders". BMJ. 298 (6678): 949–52. doi:10.1136/bmj.298.6678.949. PMC 1836181. PMID 2497870.
Wolf AP, Durham WH, eds. (2005). Inbreeding, incest, and the incest taboo: the state of knowledge at the turn. Stanford University Press. ISBN 978-0-8047-5141-4
Griffiths AJ, Miller JH, Suzuki DT, Lewontin RC, Gelbart WM (1999). An introduction to genetic analysis. New York: W. H. Freeman. pp. 726–727.
Tigers of the World, chapter 17, Thirteen Thousand and Counting: How Growing Captive Tiger Populations Threaten Wild Tigers, Philip J. Nyhus, Ronald Tilson, and Michael Hutchins
"Welfare and Conservation Implications of Intentional Breeding for the Expression of Rare Recessive Alleles" (PDF). Association of Zoos & Aquariums. June 2011. Retrieved 30 08 22