Bulldogs race during the Bulldog Derby in Los Angeles, the United States, Jan. 19, 2019. (Xinhua/Li Ying)

　　A bulldog is led in to participate in the Bulldog Derby in Los Angeles, the United States, Jan. 19, 2019. (Xinhua/Li Ying)

　　A bulldog grimaces in the Bulldog Derby in Los Angeles, the United States, Jan. 19, 2019. (Xinhua/Li Ying)

　　A bulldog takes part in the Bulldog Derby in Los Angeles, the United States, Jan. 19, 2019. (Xinhua/Li Ying)

　　A bulldog takes part in the Bulldog Derby in Los Angeles, the United States, Jan. 19, 2019. (Xinhua/Li Ying)