The White Tiger
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| Possible offspring Ww carries the gene but does not exhibit traits because it is a recessive gene |
The white tiger is not an albino tiger or sub species of tiger. It is in fact a genetic variant of the Bengal tiger. The colouration of the white tiger is a result of a recessive gene being passed on from parent to offspring. This genetic mutation can also happen naturally but is incredibly rare. The gene results in a pale coat (some may have an orange tint) with black markings which would not be seen on an albino tiger. It also results in a blue colouration of the eyes, instead of the usual yellow/green seen in tigers. This occurs because the gene that is passed on from the parent inhibits the production of pheomelanin which produces orange/yellow colouration. However, it does allow the production of eumelanin which produces the dark stripes and results in the eyes being blue instead of red like an albino tiger. To pass on the white trait, both parents must carry the recessive gene. This means that despite the gene being found in one in every 15,000, not all of these tigers will display the white trait. This also means that both parents do not need to be white to produce white offspring. However, the only way to ensure that the offspring is white is to mate two white tigers together.
Survival and Conservation
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| White tigers in captivity |
Despite the fact that white tigers are incredibly rare, there is no conservation advantage of breeding them. The white colouration gives them a disadvantaged survival. These tigers are found in forest areas where they will no longer be able to camouflage with white fur. They have no natural predators but eat by stalking their prey and surprising it. With white fur they will find this much more difficult and as a solitary animal there are no other individuals to help them catch prey. White tigers are also much more valuable to hunters and are more likely to be shot or captured, especially when the are unable to hide. Tigers are already an endangered species, with a habitat that is constantly declining. No white tigers have been spotted in the wild in over 50 years, confirming their struggle to survive. The last one was supposedly shot in 1958. While zoos and exhibitors may say they are breeding these tigers for conservation, this simply isn't true as they can not be re-released into the wild due to their inability to survive.
Inbreeding
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| Kenny - rescued white tiger Lived to the age of 10 |
The American Zoological Association (AZA) has banned members from breeding white tigers due to the fact that they are bred for profit, not for conservation. Although this mutation was not caused by inbreeding, it is thought that severe inbreeding has been a result. White tigers are a huge attraction, allowing zoos and exhibitors to bring in more visitors and make more money. This has resulted in them inbreeding white tigers to ensure they produce white offspring which are more valuable. They have also been cross bred with Siberian tigers to produce a bigger cat, but once again not providing any conservation purpose. The first white tiger was captured in India in 1951 (only 7 years before the last white tiger was spotted). Some people believe that all white tigers are descendants from this tiger and are therefore all related/inbred. Although some have claimed there is no evidence to suggest white tigers are all inbred, many have been born with severe health issues such as kidney and spine problems, crossed eyes and cleft palettes. Some offspring may be born with the orange colouration but will still inherit these defects and these cubs will often be discarded as worthless.
If these tigers are not bred in captivity it is likely that they will die out completely, as any that are produced naturally in the wild have such a struggle to survive against hunting, habitat loss and lack of camouflage. If these creatures can be kept in captivity without inbreeding, is it genetic diversity worth conserving?
