Keepers interact with killer whales at a breeding base of Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, Feb. 24, 2017. China's first killer whale breeding base was put into operation on Friday. At present, there are five male and four female killer whales here. (Xinhua/Liu Dawei)

Photo taken on Feb. 24, 2017 shows killer whales at a breeding base of Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province. China's first killer whale breeding base was put into operation on Friday. At present, there are five male and four female killer whales here. (Xinhua/Liu Dawei)