A BLACK TIGER is a rare color variant of the Tiger and is not a distinct species or geographic subspecies. There are reports and one painting (now lost) of pure black non-striped tigers (truemelanistic tigers). Most black mammals are due to the non-agouti mutation. Agouti refers to the ticking of each individual hair. In certain light, the pattern still shows up because the background color is less dense than the color of the markings.
In 1773, while in the service of British East India Company in Kerala, southwest India, artist james Forbes painted a Watercolour of a black tiger shot a few months earlier by the soldiers The painting has been lost, but Forbes' description of it survives:
I shave also the opportunity of adding the portrait of an extraordinary Tyger [sic], shot a few months ago by the Nairs in this neighborhood, and presented to the chief as a great curiosity. It was entirely black yet striped in the manner of the Royal-Tyger, with shades of a still darker hue, like the richest black, glossed with purple. My pencil is very deficient in displaying these mingled tints; nor do I know how to describe them better than by the difference you would observe in a black cloth variegated with shades of a rich Velvet.
In the early 1970s, Oklahoma City Zoo's pair of tigers had three cubs that were abnormally colored. One had the normal background color but all four limbs were abnormally dark. The second had dark feet, though these gradually grew lighter as it matured and became the normal color when it reached adulthood. The third had the normal background color, but considerable darkening over the shoulders, down both front legs, over the pelvis, and encompassing both back legs. The darkening was more-or-less the same color as the stripes. The striped pattern was only visible over the darkened areas. Unfortunately, two of the three cubs were killed by the mother, leaving only the dark-footed cub. The black cub was preserved in formalin. Quite possibly it also would have become lighter in color as it matured.
In 1999 L. A. K. Singh gave a very detailed account of the Melanistic Tiger in India. During the winter of 1975/6, two adult black tigers were seen in bright sunlight on the road leading to Matughar meadow; the sighting was made by Orissa Forest Service officials accompanied by two foreign tourists. In 1991, a black cub was seen with two adults and a normal color cub at Devasthali, though this sighting was dismissed as an optical illusion. During 1996, adult black tigers were observed several times. A yellow-striped black tiger was seen near Baladaghar . A black tiger was seen near Bachhurichara, between Patabil and Devasthali. Some time later, a yellow-striped black tiger was seen between Patabil and Devasthali.
In 1992, the pelt of another apparently true melanistic tiger was confiscated from a hunter and smuggler at Tis Hazari, south Delhi. The top of the head and back were black, while the sides showed shadow striping on a black background color. The pelt was exhibited at the National Museum of Natural History, New Delhi, in February 1993. In 1993, a young boy shot a melanistic female tiger in self defence with a bow and arrow, near the village of Podagad, west of Similipal Tiger Reserve. Initial examination suggested the background color was black with white abdominal stripes and tawny dorsal stripes. According to Valmik Thapar in Tiger: The Ultimate Guide, the only proof of black tigers is a skin with a black head and back. K. Ullas Karanth wrote in The Way Of The Tiger that a partially black tiger was recently killed by poachers in Assam.
There are reports that one of the three white tigers born in Vandalur zoo in June 2010 seems to have changed its colours — most of its body and legs are now black