A Maltese, also called the blue tiger, is a Bengal tiger with what scientists call pseudo-melanism. This means that the tiger has a great deal of black pigmentation in the fur. The Maltese tiger is known to be part of the South Chinese subspecies, the most critically endangered type of tiger.
Extra black pigmentation makes Maltese tigers look blue or gray with charcoal stripes. This coloration is believed to be a genetic mutation, as seen in domestic cats that are also called Maltese because of their slate gray fur. However, redOrbit notes that such a mutation would result in very slight stripes if any stripes were visible at all, as in black panthers, which are actually leopards with black fur. Color mutations also might occur due to inbreeding within the group, which causes weakness in otherwise healthy genetics.
The Bengal tiger is one of the most endangered species in the world, with only around 2,000 remaining in the world. Those with pseudo-melanism are extremely rare.
Blue tigers have been rarely seen in southern China as well as in Korea and Burma. However, because of how unusual these sightings are, the blue tiger was once believed to be only a myth.