The complex field of feline genetics is inclusive of all species of cat, big and small. The rules that govern the patterns and colors of a cat's coat are universal among leopards, jaguars, cheetahs, pumas, bobcats, and even your pet tabby cat. Just as the melanistic, or black, mutation is seen in several species of cat, including the domestic cat, jaguar, and leopard, the "blue" color coat gene may also be present in multiple species.
In domestic cats, the color called "blue", as in the Russian blue breed, is actually a shade of smokey bluish-gray, also called Maltese. It is this cat color-naming trend that led the blue Bengal tiger to become known as the Maltese tiger. The name was given by Desmond Collier, an American missionary who "discovered" the blue tiger and wrote about his experiences in a book, "Blue Tiger".
Collier describes the Maltese tiger-- not truly Maltese, but a color description of the Bengal tiger-- as "a delicate shade [...] changing to light gray-blue on the undersides". He states that the stripes are the same deep, dark shade as an ordinary tiger.
Since Collier's time, very few Maltese tigers have been recorded, and, indeed, some insist that they never existed at all. However, one individual, born in the 1960's at the Woodland Park Zoo, almost perfectly matched the description of Collier's blue tiger. The single confirmed Maltese tiger was a full-blooded Bengal tiger believed to have the pseudomelanistic mutation-- very similar to the "dilute black", or "blue" gene seen in domestic cats.
A few unconfirmed reports of Maltese tigers in the wild spring up on occasion. Many come from the depths of the Chinese wilderness, but other reports hail from Korea, home of the unrelated Amur tiger. If the blue tiger does indeed exist, it seems to prefer living in nearly impenetrable wilderness areas, far away from the danger of human contact.
This beckons a profound ethical question: should we hunt and capture the blue tiger? Should we breed the Maltese tiger mutation and show it in circuses and zoos? Could the blue tiger be the next white tiger, a powerful symbol of Mother Nature's love of diversity?
An animal welfare advocate would answer "absolutely not". The mutations that lead to bizarre color shifts in animals are almost always negative and associated with deformities and abnormalities, and remain rare in the wild because natural selection prevents them from being realistic adaptations.
Such is the tragic case with the white tiger, a deeply inbred, human-engineered mutation that Nature never intended to exist in the wild. White tigers, bred for profit--not conservation--now pollute the gene pools of the endangered Bengal tiger, and are so ridden with deformities that thousands of cubs must die to produce one show-quality white tiger.
If we want white, black, golden, and blue tiger mutations to exist in the wild, we owe it to our planet to work on restore habitat and protect endangered cats. With healthy wild populations of tigers restored in the wild, Mother Nature will use her own breeding program-- natural selection-- to keep healthy mutations common and horrid deformities rare. The Maltese tiger should be left alone to live and die in the wilderness as our spinning Earth sees fit.