The Sumatran tiger is a Panthera tigris sondaica population in the Indonesian island of Sumatra. This population was listed as Critically Endangered on the IUCN Red List in 2008, as it 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 tiger population in the Sunda Islands, where the Bali and Javan tigers are extinct. Sequences from complete mitochondrial genes of 34 tigers support the hypothesis that Sumatran tigers are diagnostically distinct from mainland subspecies.
In 2017, the Cat Classification Task Force of the Cat Specialist Group revised felid taxonomy and recognizes the living and extinct tiger populations in Indonesia as P. t. sondaica.