Tiger cubs yawn at a nursery house in the Xixiakou wildlife protection area in Weihai, east China's Shandong Province, May 21, 2011. The eight-year-old white tiger mother "Lili" gave birth Friday to two white female tigers and two snowwhite female tigers, belonging to a relatively rare species. These four tiger cubs now have to get fed from a "dog mother", because the tiger mother, who has already given birth to another quadruplets of three snowwhite tigers and one white tiger last September, refuses to feed her kids. (Xinhua/Yu Qibo)