Two Siberian tigers play in the snow at the Siberian Tiger Park in Harbin, Heilongjiang Province, Feb. 11, 2010. The total number of Siberian tigers in Heilongjiang Siberian Tiger Park, the world's biggest Siberian tiger captive breeding base, has reached 900 and is likely to exceed 1000 by the end of 2010. [Wang Jianwei/Xinhua]