A Siberian tiger rests at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

Siberian tiger cubs are seen at the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

A Siberian tiger rests at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

Siberian tigers rest at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

Photo taken on July 29, 2020 shows Siberian tigers on the move at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

Siberian tigers frolic at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

A Siberian tiger cub is seen at Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

Siberian tigers rest at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)

A Siberian tiger rests at a free-ranging area of the Hengdaohezi Siberian Tiger Park in Hailin, northeast China's Heilongjiang Province, July 29, 2020. The annual International Tiger Day, also known as Global Tiger Day, is celebrated on July 29. (Xinhua/Wang Jianwei)