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FEATURE ARTICLE
SHAKUNT PANDEY
A white tiger
The white tiger is a sight to behold. With the genetic mystery of the white
tigers having been solved recently, the dwindling white tiger population
could get a new lease of life.
A
white tiger is a true enchanter.
They are one of the most popular
zoo animals. Sadly, many have started
to consider it as a freak or an aberration
and not worth conserving at all. But
now armed with the latest and precise
information about its genetic roots
indicating that, white tigers are the result
of a rare but naturally occurring genetic
variant within the wild Bengal tiger
population, the voice to conserve these
majestic beasts is gaining ground.
White tigers are extinct in the wild
due to trophy hunting and their entire
population now survives in captivity.
Science Reporter, MAY 2016
The jungles of India are the birthplace
of the white tigers. The earliest record of
white tiger is found in the Akbar Nama. It
is recorded by Abul Fazal (accompanied
by a painting) in the second volume of his
work that in 1561 while Emperor Akbar
was returning to his capital Agra from
Malwa he encountered a big family of
tigers – a tigress and her five sub-adult
cubs. Out of the five sub-adult cubs two
were white tigers.
A record of a white tiger from
Poona (present Pune) was published in
the Proceedings of the Zoological Society
of London in 1891. From 1891 to 1922 white
tigers were shot in Poona (Pune), Upper
Assam, Odisha, Bilaspur and in erstwhile
princely state of Cooch Behar (West
Bengal).
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Existence of white tigers has been
recorded from Assam from time to time.
In March 1889 a white tiger was shot in
upper Assam. The Boga Bagh tea estate
in upper Assam is named after the two
white tigers that were found there in
the beginning of the 20th century. In
Assamese ‘boga’ stands for white.
In the 1920s and 1930s, fifteen white
tigers were shot in Bihar alone. The
prestigious Journal of the Bombay Natural
History Society of India (JBNHS) has
recorded seventeen cases of white tigers
shot in different parts of the country
between the years 1907 and 1933. The first
instance of an exhibition of a white tiger
in any proper organised zoo in the world
was at the Calcutta (Alipore) Zoological
Gardens in the year 1920.
FEATURE ARTICLE
The first live white tiger in captivity which was captured in
1915 in Rewa (Picture credit: JBNHS Volume 27, Year 1921)
Hunt of tigers (Two white tigers can be seen) by Akbar recorded in Akbar Nama
Renowned hunter and later turned
conservationist Jim Corbett in his famous
work Maneaters of Kumaon has also
casually referred to a white tigress whose
pictures he had taken during the winters
of 1938.
Historically, the area that is most
closely associated with the white tigers
is the erstwhile princely state of Rewa
in Madhya Pradesh. The records of the
tiger hunts were meticulously maintained
at the Palace. There are nine recorded
cases of white tigers from this region.
The first photograph of a live white tiger
was published in the Journal of the Bombay
Natural History Society (JBNHS) volume
27 of 1921. This white tiger was captured
by the ex-maharaja of Rewa in 1915. The
last white tiger was shot in 1947 by the
ex-maharaja Martand Deo Singh. No wild
white tigers have been heard of in Rewa
since 1951.
However, Martand Deo Singh is also
credited with raising the first white tiger
in captivity. It is from here that white tiger
populations have grown in the zoos of
India and other parts of the world.
In May 1951, a nine-month-old white
tiger cub, which was later christened
‘Mohan’, was captured by Martand
Singh from the forests of Rewa. He was
raised at the king’s Govindgarh palace.
On reaching maturity he was mated with
a normal coloured tigress christened
‘Begum’ who was also captured from the
forests of Rewa. From 1953-56 they had 10
cubs in three litters but none was white
coloured like the father. Mohan was then
mated with his offspring ‘Radha’ from the
second litter and on 30th October 1958 she
gave birth to four white tiger cubs – three
females and a male. A white tiger cub was
born in captivity for the first time ever!
Mohan and Radha had 14 cubs in
four litters out of which 11 were white
and three orange/normal coloured.
Two white cubs of the second litter died
within a few days of their birth. Mohan
continued to breed for sixteen years and
sired 34 cubs out of which 21 were white
and rest of normal colour. He was the
patriarch of the white tiger clan as the
ancestry of many of the white tigers in the
world can be traced back to him. He died
on 18th December 1969 at the age of 19
years. He was laid to rest with Hindu rites
and customs and a memorial was built in
his memory at Govindhgarh palace which
is visited by many.
The zoos of India and later the
United States soon became the hub of
captive breeding white tigers. But the
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Ex-King of erstwhile Rewa princely state
Martand Deo Singh – the man behind captive
breeding of white tigers
Association of Zoos and Aquariums
(AZA) US banned the breeding of white
tigers in all its affiliated zoos in the year
2011 thereby pushing the entire existing
white tiger population of America in the
private domain.
In India the captive white tiger
population continues to thrive in its zoos.
It is estimated that there are around 200
white tigers surviving in the world and
half of these are in our country.
The Nandankanan Zoological Park
of Odisha holds the Guinness book
of world record for having the largest
captive population of white tigers which
is pegged at 34. Now there are plans afoot
Science Reporter, MAY 2016
FEATURE ARTICLE
Mohan, the patriarch of the surviving white tiger family
(Picture credit: JBNHS, 1959, Volume 56)
Radha with her cubs – the birth of the first white tigers in captivity
(Picture Credit: JBNHS, 1959, Volume 56)
Mohan and Radha had 14 cubs in four litters out of
which 11 were white and three orange/normal coloured.
Two white cubs of the second litter died within a few
days of their birth. Mohan continued to breed for sixteen
years and sired 34 cubs out of which 21 were white and
rest of normal colour.
to establish a white tiger breeding centre
at Mukundpur Zoo in Satna district of
Rewa division in Madhya Pradesh.
The habits and behaviour of a normal
coloured tiger and white tigers are more
or less similar but findings particularly in
the US reveal that due to poor eyesight a
white tiger tends to be more aggressive
than the normal coloured tiger. There is
no difference in their breeding season,
litter size, gestation period and mating
behaviour. The average life span is also
similar varying from 16 to 20 years.
The colour of the coat of white tigers
varies from white to off-white to cream
with light brown to ash-grey stripes. They
have mottled grey-pink nose pad instead
of the pure pink colour as in normal
coloured tigers; their eyes are ice blue or
pale blue in colour.
On an average they are slightly larger
and heavier than the normal coloured
tigers. The average length and weight
of a white tiger cub at birth is 53 cm
and 1.37 kg respectively as compared to
50 cm length and 1.25 kg weight of a
normal coloured tiger cub. An adult
white tiger weighs 120 to 130 kg while the
weight of a normal coloured tiger ranges
from 105 to 120 kg (The White Tiger,
JH Desai and AK Malhotra)
Science Reporter, MAY 2016
White tigers are not albinos.
Albinism means lacking total colour
pigment in the hair and the skin; even
eyes lack pigmentation which gives
a pink or reddish appearance. There
is only one recorded instance of true
albinism in tigers. It is reported in the
Journal of Bombay Natural History Society
Volume No. 28 that in the year 1922 in the
erstwhile princely state of Cooch behar in
a family of man-eating tigers consisting
of a tigress and her four cubs, two cubs
(a male and a female) were albinos with
light colour coats and pink eyes. They
were found in a very bad condition and
they trotted around like big dogs before
being shot. They also had long necks.
In mammals, fur colour is determined
by the pigment melanin. There are two
types of melanin – eumelanin (black to
brown) and pheomelanin (red to yellow).
The amount, ratio and distribution of
eumelanin and pheomelanin in hair
determine the coat colour of an animal.
The white tiger is a rare colour morph of
the Royal Bengal Tiger. Contrary to their
orange coloured brethren the white tigers
lack pheomelanin, with minor (or no)
change in eumelanin, and have white fur
interspersed with sepia-brown stripes.
Given
sporadic
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but
consistent
observation of white tigers in the wild
over centuries of records, it is reasonable
to speculate that the white tiger
colouration is likely a stable genetic trait
in a recessive manner. Data from white
tiger captive breeding (The white tiger of
Rewa and gene homology in the Felidae.
R. Robinson, Genetica, 1969) has confirmed
that the striped white coat colour is
inherited as an autosomal recessive trait.
The white tigers are considered to
be leucistic and regarded to carry the
recessive “Chinchilla” allele. This allele is
known as the “inhibitor” allele because it
inhibits pigment production.
Two pioneering research works
by a team of Chinese scientists with the
Peking University, Beijing, has removed
the genetic mystery about the white coat
of the white tigers – why the white tiger
has lost its colour but has kept its stripes.
R. Robinson ibid in his work had
postulated that white tigers arose because
of a recessive allele at the chinchilla locus
currently known as the tyrosinase gene.
Xu et al tested Robinson’s hypothesis
by sequencing the TYR (tyrosinase)
gene along with other key coat-colourassociated genes MC1R (melanocortin
1 receptor), ASIP (agouti signalling
protein), TYRP1 (Tyrosinase-related
protein 1) and SLC7A11 (solute carrier
family 7, member 11) in both white and
orange tigers. No genetic association was
detected among these genes, suggesting a
different mechanism entirely.
Next, a genome-wide association
study (GWAS) was conducted in a twogeneration family of 16 tigers segregating
at the white colour trait based on whole
FEATURE ARTICLE
A white tigress with her cub (Picture credit: Nandankanan Zoo, Odisha)
The habits and behaviour
of a normal coloured tiger
and white tigers are more
or less similar but findings
particularly in the US
reveal that due to poor
eyesight a white tiger tends
to be more aggressive than
the normal coloured tiger.
genome sequencing and restriction
site
associated
DNA
sequencing
(RAD-seq). The approach mapped the
white tiger colour coat colour trait to the
gene SLC45A2 (solute carrier family 45
member 2). Further, an alanine to valine
substitution (A477V) was identified in
SLC45A2 and found to be co-segregated
with the white coat colour trait. This
A477V mutation in SLC45A2 was
validated in an additional 130 unrelated
tiger individuals. A477V is located in
the evolutionary conserved amino acid
residue site, and predicted to affect the
function of the SLC45A2 protein by three
dimensional protein structure simulation.
Xu Xiao et al. concluded that white tigers
are caused by the A477V mutation in the
SLC45A2 gene (The genetic basis of white
tigers, Current Biology, 2013)
A recent study on felid coat pattern
formation has identified a key gene Edn3.
This gene expression is increased in
dark-coloured regions compared to lightcoloured regions. The pattern-sustaining
mechanism is most likely to be conserved
among felids, and perhaps tigers have
preserved the region-specific expression
pattern of Edn3 in the striped area.
The scientists suggest that the A477V
mutation in SLC45A2 may diminish
melanin biosynthesis over the entire coat
in white tigers, but the high expression of
Edn3 sustains eumelanogenesis in some
regions according to pattern specifying
mechanisms, resulting in white tiger’s
iconic sepia brown stripes (How the
White tiger lost its color, but kept its
stripes, XU Xiao et al. Science China Volume
57 October 2014).
Although deliberate inbreeding
of white tigers has maintained their
recessive colouration, it has also led to a
host of health problems. It has resulted in
sterility or reduced fecundity, shortened
lifespan, vision abnormalities, shortening
of limbs, twisted necks, crooked tails,
kidney deformities, weakened immune
systems, poor lactation in females and
numerous still births.
Further, in the United States some
white tigers of the North American line
of white tigers suffered from a facial
deformity known as bull-dog face, which
is a distortion of the head, lacking bone
development in the middle facial and
upper jaw portion. The condition is
characterised by a snubbed nose, domed
head, jutting jaw, and wide set eyes with
an indentation between the eyes. White
tigers cannot see as well as normal tigers
and suffer from photophobia. White tigers
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with crossed eyes are not always born
that way; they may develop the condition
later in life. Parkinson’s syndrome has
also been observed in white tigers.
The white tiger’s distinguishing
characteristics arise from a single
mutation, the substitution of one amino
acid for another – valine for alanine – in
the “solute carrier” protein geneticists call
SLC45A2. Its job is to basically transfer
specific molecules across cellular barriers.
Similar variations in SLC45A2 have been
observed in other vertebrate species
ranging from humans to chickens. With
rare exceptions the swap’s only effect on
the animal is of external pigmentation.
The Chinese researchers who solved
the genetic mystery of the white tigers
say that since the crucial mutation in
white tigers has been identified it will
be possible to identify and crossbreed
pairs of Royal Bengal tigers, each one
possessing a single copy of the recessive
gene. Basic Mendelian rules give a 25%
probability that any given pregnancy
will produce white tiger offspring while
significantly expanding the gene pools of
healthy animals.
Once wiped out due to the greed for
trophy hunting, it is time we made sure
that the roar of this majestic creature does
not fall silent forever.
Mr Shakunt Pandey is a freelance journalist
based in Kolkata. Address:-‘Lake Utsav’,
P-331 Parnashree Pally, Flat No. 3A, 3rd Floor,
Kolkata-700060; Email: shakuntpan33@gmail.
com/[email protected]
Science Reporter, MAY 2016