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All wild white tigers were a color variation of Bengal tigers. White
tigers in the wild were recorded in India during the Mughal Period from
1556 to 1605 AD. At least 17 instances were recorded in India between 1907
and 1933 in Orissa, Bilaspur, Sohagpur and Rewa. Wild white tigers were
very rare, and none have been reported in the wild since the 1950s.
White tigers differ from ordinary orange tigers (if a tiger can be
referred to as ordinary) in having ice-blue eyes, a pink nose, and creamy
white fur with chocolate stripes. White tigers are not albinos; their
color is caused by a double recessive allele. A Bengal tiger with two
normal alleles or one normal and one white allele is colored orange. Only
a double dose of the mutant allele results in white tigers.
How frequently do white tigers appear in nature? No one knows. But we do
know that in the last 100 years, only about a dozen such white tigers have
been seen in India (white forms have never been reported for any of the
other subspecies). During this same century, the Bengal tiger population
has dropped from 40,000 to a low of 1,800 tigers, and approximately
100,000 have lived and died, suggesting that as few as one in every 10,000
tigers is white.
The white tiger collection in North American zoos traces its ancestry to a
single white male known as Mohan, captured in 1951 in central India. It
did not take long for the Maharajah who captured him to figure out that
the only way to produce additional white tiger cubs was to breed Mohan
back to his daughter, who gave birth to the first generation of
captive-born white tigers in this century. One of these granddaughters,
Mohini, was bred with her uncle and half-brother, an orange male called
Sampson. It was through Mohini that the white tiger line came to the
United States through the National Zoo in Washington D.C., From there, two
of Mohini's offspring, a brother and sister, were bred at the Cincinnati
Zoo and their daughter, Kesari, founded the Cincinnati white tiger line.
White tiger cubIn Cincinnati, the inbreeding continued. Bhim, a white son
of Kesari, was mated to his sisters Kamala and Sumita, and so on.
Altogether, the average inbreeding coefficient of the white tiger lineage
is much higher that that of either Sumatran of Siberian tigers managed by
the tiger SSP which is methodically working towards minimizing the average
inbreeding coefficient of its captive population. This translates into a
healthier population and decreases the probability of a number of
reproductive and disease problems associated with inbreeding.
An SSP is a breeding strategy followed by participating zoos that is
designed to maintain small self-sustaining populations of endangered
species in captivity. Every breeding recommendation is designed to
minimize the average inbreeding coefficient of the population and to
equalize the genetic representation of each wild-caught animal ("founders"
of the captive population). With some 63 such species blueprints in hand,
zoos are increasingly becoming last-ditch refuges for endangered species,
as a kind of biological (rather than biblical) Noah's ark. Already on
board are several species now extinct in the wild that survive only in
zoos, including Pere David's deer and Asian wild horses, and three
additional species, the California condor, Arabian oryx, and black-footed
ferret, are currently making their way back into the wild thanks to
captive breeding.
The white tiger controversy among zoos is a small part ethics and a large
part economics. For example, the tiger SSP has condemned breeding white
tigers because of their mixed ancestry (most have been hybridized with
other subspecies or are of unknown lineage) and because they serve no
conservation purpose. Owners of white tigers say white tigers are popular
exhibit animals and help increase zoo attendance and, at $60,000 each,
revenues as well. The same story can be applied to the selective
propagation of melanistic leopards, white lions, king cheetahs, and other
phenotypic aberrations.
However, there is an unspoken issue that shames the very integrity of
zoos, their conservation programs, and their message to the visiting
public. To produce white tigers or any other phenotypic curiosity,
directors of zoos and facilities must continuously inbreed, father to
daughter, to granddaughter, and so on. At issue is a Courtesy Magnetika666
- http://www.flickr.com/photos/magnetika666/134992722/contradiction of
fundamental genetic principles upon which all SSPs for endangered species
in captivity are based. White tigers are an aberration artificially bred
and proliferated by a few zoos, private breeders, and circus folks, who do
this for economic rather than conservation reasons.
White Tigers Without Stripes
White tigers showing no stripes have been recorded. A "wholly white tiger,
with the stripe-pattern visible only under reflected light, like the
pattern of a white tabby cat, was exhibited in the Execter Change
Menagerie in the early part of the nineteenth century and described by
Hamilton Smith. Another citing of a "tiger without stripes" was reported
by Sagar and Singh (1989) from Similipal Reserve, Orissa.
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