<Tr> <Td> Sumatran tiger (P. t . sondaica), formerly P. t . sumatrae Pocock, 1929 </Td> <Td> It is the smallest of all living tigers . Males range in total length from 220 to 255 cm (87 to 100 in) and weigh between 100 to 140 kg (220 to 310 lb), while females range between 215 to 230 cm (85 to 91 in) and 75 to 110 kg (165 to 243 lb). The reasons for its small size compared to mainland tigers are unclear, but probably the result of competition for limited and small prey . The population is thought to be of Asia mainland origin and to have been isolated about 6,000 to 12,000 years ago after a rise in sea - level created the Indonesian island of Sumatra . <P> The population is the last surviving of the three Indonesian island tiger populations . It is listed as Critically Endangered on the IUCN Red List . By 2008, the wild population was estimated at between 441 and 679 in 10 protected areas covering about 52,000 km (20,000 sq mi). </P> </Td> <Td> </Td> </Tr> <P> The population is the last surviving of the three Indonesian island tiger populations . It is listed as Critically Endangered on the IUCN Red List . By 2008, the wild population was estimated at between 441 and 679 in 10 protected areas covering about 52,000 km (20,000 sq mi). </P> <P> The tiger's closest living relatives were previously thought to be the Panthera species lion, leopard and jaguar . Results of genetic analysis indicate that about 2.88 million years ago, the tiger and the snow leopard diverged from the other Panthera species, and that both may be more closely related to each other than to the lion, leopard and jaguar . Results of a phylogeographic study indicate that all living tigers had a common ancestor 72,000--108,000 years ago . </P> <P> Fossil remains of the Longdan tiger were found in the Gansu province of northwestern China . This species lived at the beginning of the Pleistocene, about 2 million years ago, and is considered to be a sister taxon of the modern tiger . It was about the size of a jaguar and probably had a different coat pattern . Despite being considered more "primitive", the Longdan tiger was functionally and possibly ecologically similar to the modern tiger . As it lived in northwestern China, that may have been where the tiger lineage originated . Tigers grew in size, possibly in response to adaptive radiations of prey species like deer and bovids, which may have occurred in Southeast Asia during the early Pleistocene . </P>

When did the first tiger appeared on earth