There are not seven levels of tiger classifications or subspecies but six, and they are the Sumatran, Amur, Bengal, Indochinese, South China and Malayan tigers. In addition, three other subspecies became extinct in the 20th century: Bali, Caspian and Javan tigers.
The largest subspecies of tiger, the Amur, or Siberian, tiger, whose males can reach over 600 pounds, inhabits the Russian Far East and the border areas of China and North Korea. Almost extinct by the 1940s, due to conservation efforts by Russia, the population has reached over 400 as of 2014. The second-largest species, the Bengal Tiger, is the most numerous with around 2,500 adults still in the wild. It is found mainly in India but also in Nepal, Bhutan, Bangladesh, China and Myanmar. The Indonesian Tiger is found in the mountainous parts of Thailand, Vietnam, Cambodia, Laos, China and Myanmar. It has the largest area of habitat of any tiger species, but as of 2014, there are only about 350 individuals left.
The Malayan Tiger, found only on the Malayan peninsula, was only found to be a separate species in 2004 due to genetic analysis of DNA. Only about 500 adults survive in the wild. The South China Tiger is considered one of the 10 most endangered animals in the world. As of 2014, only about 65 individuals exist in captivity, and there has not been a wild sighting in more than 25 years. The Sumatran Tiger, the smallest of the Tiger species, has about 400 individuals remaining and is found mostly in national parks on the island of Sumatra in Indonesia.