The Tasmanian tiger had been around for approximately four million years when European exploration began. Earlier, smaller species related to the tiger are dated much older with some fossils found to be 23 million years old. Thylacine rock art - like this one in the Ubirr region of the Kakadu National Park, 253 kms East of Darwin - date back to 1,000 BC. Originally spread throughout mainland Australia and New Guinea, the tigers lost territory to incoming dogs, who, as carrion eaters were less choosy feeders than the nocturnal prey-hunting thylacine. The tigers became extinct on the mainland around 2,000 years ago but survived on the remote island of Tasmania until the last one died in Hobart Zoo in 1936. With tiger bounties being paid as early as 1830, an animal that had been on the planet for 23 million years was wiped out by man in little more than a century.