This document discusses several endangered tiger subspecies and the threats they face. It describes how Sumatran, Siberian, Bengal, and South China tigers have faced major population declines due to habitat loss and poaching. Sumatran tigers now number less than 500, while Siberian tigers were down to less than 50 individuals in the mid-20th century. Efforts are underway to protect and breed these tigers in captivity to help recover their wild populations. However, all four subspecies described remain critically endangered.