tigers - physical characteristics
Today, tigers are perhaps the most recognisable of all the cats (with the possible exception of the lion). They typically
have rusty-reddish to brown-rusty coats, a whitish medial and ventral area, a white "fringe" that surrounds the face, and
stripes that vary from brown or gray to pure black. The form and density of stripes differs between subspecies (as well as the
ground coloration of the fur; for instance, Siberian tigers are usually paler than other tiger subspecies), but most tigers
have over 100 stripes. The pattern of stripes is unique to each animal, and thus could potentially be used to identify individuals,
much in the same way as fingerprints are used to identify people. This is not, however, a preferred method of identification, due
to the difficulty of recording the stripe pattern of a wild tiger. It seems likely that the function of stripes is camouflage,
serving to help tigers conceal themselves amongst the dappled shadows and long grass of their environment as they stalk their
prey. The stripe pattern is found on a tiger's skin and if shaved, its distinctive camouflage pattern would be preserved. Like
other big cats, tigers have a white spot on the backs of their ears.
Tigers have the additional distinction of being the heaviest cats found in the wild. They also have powerfully built legs and
shoulders, with the result that they, like lions, have the ability to pull down prey substantially heavier than themselves. However,
the subspecies differ markedly in size, tending to increase proportionally with latitude, as predicted by Bergmann's Rule. Thus,
large male Siberian Tigers (Panthera tigris altaica) can reach a total length of 3.5 m "over curves" (3.3 m. "between pegs") and a
weight of 306 kilograms, which is considerably larger than the sizes reached by island-dwelling tigers such as the Sumatran, the
smallest living subspecies with a body weight of only 75-140 kg. Tigresses are smaller than the males in each subspecies, although
the size difference between male and female tigers tends to be more pronounced in the larger subspecies of tiger, with males weighing
up to 1.7 times as much as the females. In addition, male tigers have wider forepaw pads than females. This difference is often used
by biologists in determining the gender of tigers when observing their tracks.
colour variations - white tigers
There is a well-known mutation that produces the white tiger, technically known as chinchilla albinistic, an animal which is rare
in the wild, but widely bred in zoos due to its popularity. Breeding of white tigers will often lead to inbreeding (as the trait is
recessive). Many initiatives have taken place in white and orange tiger mating in an attempt to remedy the issue, often mixing subspecies
in the process. Such inbreeding has led to white tigers having a greater likelihood of being born with physical defects, such as cleft
palates and scoliosis (curvature of the spine). Furthermore, white tigers are prone to having crossed eyes (a condition known as strabismus).
Even apparently healthy white tigers generally do not live as long as their orange counterparts.
Recordings of white tigers were first made in the early 19th century. They can only occur when both parents carry the rare gene found in
white tigers; this gene has been calculated to occur in only one in every 10,000 births. The white tiger is not a separate sub-species,
but only a colour variation; since the only white tigers that have been observed in the wild have been Bengal tigers (and all white
tigers in captivity are at least part Bengal), it is commonly thought that the recessive gene that causes the white colouring is probably
carried only by Bengal tigers, although the reasons for this are not known. Nor are they in any way more endangered than tigers are generally,
this being a common misconception. Another misconception is that white tigers are albinos, despite the fact that pigment is evident in the
white tiger's stripes. They are distinct not only because of their white hue; they also have blue eyes and pink noses.
colour variantons - golden tabby tigers
In addition, another recessive gene may create a very unusual "golden tabby" colour variation, sometimes known as "strawberry".
Golden tabby tigers have light gold fur, pale legs and faint orange stripes. Their fur tends to be much thicker than normal. There
are extremely few golden tabby tigers in captivity, around 30 in all. Like white tigers, strawberry tigers are invariably at least
part Bengal. Both white and golden tabby tigers tend to be larger than average Bengal tigers.
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