Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)

Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)

Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)

Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)

Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)

Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)

Photo taken on July 11, 2019 shows Siberian tigers at the Siberian tiger park of the China Hengdaohezi Feline Breeding Center in Hailin, northeast China's Heilongjiang Province. Over 30 Siberian tiger cubs were born in the park from the end of February this year. (Xinhua/Wang Jianwei)