White Tigers
Introduction and description
The White Tiger is not a separate sub-species of Tigers. They are in principle just White Bengal Tigers also known as Snow Tigers, Snow White Tigers or White Tigers. White Tigers have recessive genes in their genomes that gives them their white color.
White Tigers have become quite common in Zoo's in the United States, Europe and Asia. This is due to a single white Tiger imported from India long time ago. Since then Zoo's have done a lot of breeding - and inbreeding - to promote the gene giving the White Color. They've even mixed White Bengal Tigers with the larger Siberian Tigers to get larger specimens in Zoo's attracting more visitors.
It should be noted that the name Siberian Tiger is also a bit misleading, as they do not live in Siberia - they live in the Amur Region of South Eastern Russia close to the Amur and Ussuri River. The best name for the Siberian Tiger would probably be the Amur Tiger.
In nature, White Bengal Tigers arises from the mating of two Bengal Tigers with recessive genes for the white color of fur. The gene is recessive meaning that offspring (cubs / kittens) only become white if they inherit the recessive gene from both parents. It's the same principle as with brown and blue eyes. The inbreeding producing all these White Tigers isn't very good and definitely not healthy for the Tigers! In nature Snow Tigers (White Tigers, White Bengal Tigers) have, at least theoretically, a less chance of surviving than normal colored Tigers due to their lack of camouflage compared to the normal Yellow Tigers. There are however probably only a few or perhaps even no White Tigers outside captivity at all.
Below is a very simplified illustration (Fig 1) of how it works. Consider to yellow Bengal Tigers mating. If they are both carriers of the recessive gene there's a 25 percent chance that their cubs will be white. If a white and a yellow Bengal Tiger mates there's a 50% chance that the offspring will be white. The chances of getting more Snow Tigers can be enhanced by letting Tigers mate
their own sons and daughters.
Fig 1.
Illustration of how genes control the color of Bengal Tigers
Sometimes the talk about species and sub-species can be a little bit confusing when it comes to tigers. The distinguishing between species is based on morphology rather than genetics, because the latter wasn't invented when the sub-species were defined. Snow Tiger have never been an
independent species - they are 'just' a beautiful variation of the Bengal Tiger.
The future of the Bengal Tiger and the White Bengal Tigers does not look very bright. The population of Snow Tigers outside captivity is hard to estimate, since they are not seen very often in their natural habitat. The population of Bengal Tigers is split into several very small groups of tigers, each of them probably too small to sustain a healthy population without
inbreeding in the long run.
The number of White Tigers among the population of Bengal Tigers solely depends on the frequency of the recessive gene within the population. It is however a fact, that inbreeding produces more homozygotes - the relative frequency of either WW or YY homozygotes will increase in a population declining in numbers
due to inbreeding.
A male White Bengal Tiger normally reaches a weight of 180-260 kg. while a female normally weights 150-200 kg. Larger individual have been observed. For more information about the appearance of the White Tiger I suggest the video or picture section of this webpage.
Habitat
The White Tiger is found in Bangladesh and the Eastern parts of India, Nepal, Himalaya and Burma and the Bay of Bengal. It lives in all sort of environments such as forests in high altitudes, mangroves, arid and swampy areas. It has been said, that the best chance of seeing a White Bengal Tiger is in Himalaya, but this is probably not true anymore.
Winter temperatures in the United States and Europe do not pose any problems to any tigers, so tigers in captivity don't suffer in that respect. Tigers need a large area where they can hunt because they demand large amounts of meat to feed themselves and their cubs.
Cubs
Cubs from White Tigers are either white or yellow. It's all random and it's not uncommon to see cubs with different colors in the same litter (Fig 2). The litter size of Bengal Tigers is anywhere from 1 to 4 cubs depending on chance and the availability of prey for the female. The most common litter size is however two kittens.
Fig 2. Different colored cubs in the same litter
The pregnancy last for only 15 weeks. The cubs are born blind, just like notmal cat kittens. The cubs stay with there mother for 2-3 years. For the first 8 weeks the cubs only gets milk but from then on they will gradually swift to eating meat and after 6 months they are weaned off.
The father of Bengal Tiger cubs doesn't help in raising the cubs, but he's important in the sense that the female is in his territory. If another male Tiger conquers the territory, the cubs are in danger of being killed by the new male. The advantage of this behavior is, that the strongest male won't have to compete with weaker Tigers offspring in the future. Furthermore the female tiger will be me more prone of having his cubs in the future.
Fight for territory among Tigers
Males fight for territory in order to impregnate as many females as possible - thereby spreading their own genes. Females fight for territory to sustain and to feed their cubs. There can be several tigers on the same territory. It's also very common, that female offspring stay close to the territory in which they were raised.