Three Siberian tiger cubs suck milk at the Heilongjiang Siberian Tiger Garden, the world's largest breeding center for Siberian tigers, in Harbin, capital of northeast China's Heilongjiang Province, May 6, 2014. A 12-year-old Siberian tiger gave birth to three female cubs on April 26 in the breeding center. About 100 Siberian tiger cubs are expected to be born in the center this year. (Xinhua/Wang Jianwei)