Giant panda Meng Meng gave birth to twin female cubs at the Chengdu Research Base of Giant Panda Breeding in Southwest China's Sichuan province on May 23, 2018. The new born cubs, weighing 149.9 grams and 110.7 grams respectively, are the world's first pair of twin panda cubs born in 2018. [Photo/Chengdu Research Base of Giant Panda Breeding]

Giant panda Meng Meng gave birth to twin female cubs at the Chengdu Research Base of Giant Panda Breeding in Southwest China's Sichuan province on May 23, 2018. [Photo/Chengdu Research Base of Giant Panda Breeding]

Giant panda Meng Meng gave birth to twin female cubs at the Chengdu Research Base of Giant Panda Breeding in Southwest China's Sichuan province on May 23, 2018. [Photo/Chengdu Research Base of Giant Panda Breeding]

Giant panda Meng Meng gave birth to twin female cubs at the Chengdu Research Base of Giant Panda Breeding in Southwest China's Sichuan province on May 23, 2018. [Photo/Chengdu Research Base of Giant Panda Breeding]