The Sumatran tiger (Panthera tigris sumatrae) is a rare tiger subspecies that inhabits the Indonesian island of Sumatra. It has been listed as Critically Endangered on the IUCN Red List in 2008 as the population was estimated at 441 to 679 individuals, with no subpopulation larger than 50 individuals and a declining trend.The Sumatran tiger is the only surviving member of the Sunda Islands group of tigers that included the now extinct Bali tiger and Javan tiger.