A rare Siberian tiger attacked and killed a tour bus driver in northern China as he was checking his vehicle that was trapped in the snow, Chinese media reported.The tiger pounced on driver Jin Shijun and dragged him into the forest at the world's largest Siberian tiger breeding base in the northern province of Heilongjiang, the state-run Xinhua News Agency said.The report on Monday's attack cited a spokesman at the base, which has about 1,000 Siberian tigers.Siberian tigers are one of the world's rarest species. An estimated 300 are left in the wild, but more than 5,000 are kept on farms and wildlife parks across China.