| Tiger (Panthera tigris) | |||||||||
|
The largest cat in the world is the Amur, aka Siberian, tiger. Overall listed as Endangered, with the Amur, South China, and Sumatran subspecies as Critically Endangered. Three subspecies (Caspian, Bali, Javan) have become extinct since the 1950's. Overall, there are probably no more than 2500 breeding adult tigers in the wild. There are no subpopulations that contain over 250 mature individuals. There is a continuing decline all over their range due to poaching, persecution, and habitat loss.
White tigers are not a separate subspecies. They are Bengal or Siberian-Bengal hybrids exhibiting a recessive color. The correct term for white tigers is chinchilla albinistic: blue eyed, pale-coated, but having a striped pattern. The chinchilla gene is recessive to the normal orange color gene. A separate "wide-band" gene, also recessive, controls spacing and coloration of the stripes, resulting in "pure white" and "golden tabby" tigers. In the 1950's, Mohan (the first captive white tiger to be successfully bred) was mated with Radha, one of his daughters. This produced four white cubs. Typical signs of inbreeding include crossed eyes, curvature of the spine, twisted necks and shortened tendons in the legs. As inbreeding worsens, the number of miscarriages, stillbirths, and unexplained infant mortalities rise. Cubs that do survive become prone to mysterious illness.
Today white tigers are so numerous in captivity that many are in sanctuaries for unwanted tigers. In captivity tigers breed well, with up to 6 cubs in a litter. Many of the tigers in circuses or with private owners are generic (not a pure subspecies and/or parental lineage unknown), as are some in zoos.
|