Chinese male giant panda Le Bao is seen at the Panda World of Everland Resort in the city of Yongin, South Korea, on April 18, 2019. Chinese male giant panda Le Bao and female giant panda Ai Bao, whose names mean pleasant and lovely treasures, began to be made public on April 21, 2016 at the 3,300-square-meter Panda World of Everland, South Korea's largest theme park located around 40 kilometers from capital Seoul. (Photo:Xinhua)

Chinese female giant panda Ai Bao rests on a tree at the Panda World of Everland Resort in the city of Yongin, South Korea, on April 18, 2019. Chinese male giant panda Le Bao and female giant panda Ai Bao, whose names mean pleasant and lovely treasures, began to be made public on April 21, 2016 at the 3,300-square-meter Panda World of Everland, South Korea's largest theme park located around 40 kilometers from capital Seoul. (Photo:Xinhua)

Visitors watch the Chinese male giant panda Le Bao eating bamboos at the Panda World of Everland Resort in the city of Yongin, South Korea, on April 18, 2019. Chinese male giant panda Le Bao and female giant panda Ai Bao, whose names mean pleasant and lovely treasures, began to be made public on April 21, 2016 at the 3,300-square-meter Panda World of Everland, South Korea's largest theme park located around 40 kilometers from capital Seoul. (Photo:Xinhua)

Chinese female giant panda Ai Bao eats bamboos at the Panda World of Everland Resort in the city of Yongin, South Korea, on April 18, 2019. Chinese male giant panda Le Bao and female giant panda Ai Bao, whose names mean pleasant and lovely treasures, began to be made public on April 21, 2016 at the 3,300-square-meter Panda World of Everland, South Korea's largest theme park located around 40 kilometers from capital Seoul. (Photo:Xinhua)

Chinese male giant panda Le Bao sleeps at the Panda World of Everland Resort in the city of Yongin, South Korea, on April 18, 2019. Chinese male giant panda Le Bao and female giant panda Ai Bao, whose names mean pleasant and lovely treasures, began to be made public on April 21, 2016 at the 3,300-square-meter Panda World of Everland, South Korea's largest theme park located around 40 kilometers from capital Seoul. (Photo:Xinhua)

Chinese male giant panda Le Bao eats bamboos at the Panda World of Everland Resort in the city of Yongin, South Korea, on April 18, 2019. Chinese male giant panda Le Bao and female giant panda Ai Bao, whose names mean pleasant and lovely treasures, began to be made public on April 21, 2016 at the 3,300-square-meter Panda World of Everland, South Korea's largest theme park located around 40 kilometers from capital Seoul. (Photo:Xinhua)