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)

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)