Erythrism or erythrochroism refers to an unusual reddish pigmentation of an animal's hair, skin, feathers, or eggshells. Causes of erythrism include: Genetic mutations which cause an absence of a normal pigment and/or excessive production of other…

They are tigers with a color variation caused by a genetic recessive gene mutation called erythrism. Instead of black stripes, their stripes are replaced by orange or brown. There are only 40-50 of these tigers remaining in the world.